# About fertilysers for Slipper orchids.



## Brabantia (Dec 1, 2010)

Since a couple of years MSU fertilysers are the "best seller'' for feeding orchids in general. The composition of this fertilyser has been optimized for Phalaenopsis culture. Is this fertilyser the best for Paphiopedilum and Phragmipedium? I ask this question because we know that slipper orchids are sensitive to fungal and bacterial diseases and that phosphorus and more specifically potassium increase the cells resistance to these two type of attacks. A fertilyser having more phosphorus and more potassium (in comparison with nitrogen) would not be more appropriate? I think a fertiliser like this 10-11-18 of course with calcium and magnesium added.


----------



## Ray (Dec 1, 2010)

The original "MSU" fertilizer (Sold under the Greencare brand name) was designed to be used for a mixed collection of orchids, and was not optimized for any one genus. 

I didn't know that paphs were particularly susceptible to bacterial and fungal diseases. In fact, mine seem to be generally less effected than other genera in my collection. (They are doing well with the MSU stuff, by the way.)

Increasing the content of phosphorus does nothing beneficial, as most of it remains unused by the plants.


----------



## Ernie (Dec 1, 2010)

I agree with Ray. Our slippers have fewer issues than Phals, oncids, catts, zygopetalinae, etc. We use MSU and DynaGro formulas with ProteKt and Peters and a couple different things we got at the pot store and overall our plants seem well nourished. MSU and the similar formulae are our go to feeds. I doubt a tweak in nutrition from our mixed diet would have any noticeable result in a mixed collection, but it all depends on the dynamic of your growing area with your water, mix, etc. As good as the MSU stuff is, I will (probably) never recommend a hobbyist rely on any _single _fertilizer formula. The unknowns are just too great and time too precious for hobbyists and small commercial growers to properly randomize a study which would take acres and years and a substantial dollar investment to complete properly. Shoot, even within the Paphs, there could be a difference in how species in the different sections utilize nutrients, and a broad scale study like this might logically include something fast-growing like maudiae hybrids. 

So, my quick answer is: if it concerns you, or if you notice signs of deficiencies, rotate your fertilizer formulas and feed weakly weekly with a plain water flush once in a while (monthly at least).


----------



## NYEric (Dec 1, 2010)

Pot store!?


----------



## goldenrose (Dec 1, 2010)

The subject of fertilizers comes up on a regular basis, we seem to rehash previous info. If whatever you're doing & it's working for you, why change it? Hadley Cash was in last month for IOS, he recommended nothing special, whatever is easy to get your hands on. Use a high nitrogen formula during the growing season, switch to a blossom booster in fall and it doesn't hurt to go without a couple of months in the winter. 
....K.I.S.S.


----------



## Eric Muehlbauer (Dec 1, 2010)

Eric....Pot Store is what we call the hydroponics store on Horace Harding in Flushing. Somehow I don't think that orchid growers are the primary customers at a hydroponics store....


----------



## Ernie (Dec 1, 2010)

Eric Muehlbauer said:


> Eric....Pot Store is what we call the hydroponics store on Horace Harding in Flushing. Somehow I don't think that orchid growers are the primary customers at a hydroponics store....



Yeah, it's a general term for a hydroponics store. Locally, it's Urban Sunshine on University down the street from UCF. Amazing how every college neighborhood has a hydroponics store and a homebrew store! The employees there are most knowledgable about lights, ferilizer, etc.


----------



## chrismende (Dec 2, 2010)

I get totally boggled when I look at all the fertilizer choices at my favorite local pot store: PlantItEarth. And they tell me that the DynaGrow and Protekt are the ones orchid growers use most of their selections. They seem to have potions for so many uses. I've been using a Dutch "magic formula" for root growth promotion that may not even list the real ingredients on it's label for the US. MaxSea 13-13-13, Protekt, and the "Roots Excelurator" stuff has been my trio for each fertilizing lately. No controls, though. On my next flask of something not too expensive, I'll do at least a small control group of halves.


----------



## TyroneGenade (Dec 2, 2010)

Anyone using Kelpak or some other foliar feed?


----------



## Ray (Dec 2, 2010)

Oh Tyrone... Now you've done it, and opened another can of worms.

(Hee Hee) I'll start:

In my opinion, foliar feeding of orchids is - relatively speaking - a waste of time.

As they have evolved with a "water retention" strategy:
1) Orchids don't have a lot of leaf stomata compared to terrestrial plants.
2) Most of the stomata tend to be concentrated on the under-sides of the leaves.
3) Many orchids have a "waxy" layer on the leaves to further limit transpiration.
4) CAM plants even close their stomata in the daytime (when we would most likely feed).

I suspect that while there may be some - very limited - benefit to foliar feeding, what we are truly experiencing is fertilizer dripping off of the leaves onto the root system. One plant biologist even told me that plants with "fan structures" are _designed_ to channel liquids down to their centers, where the droplets will coalesce and drip to the roots.


Back to the original fertilizer question - I rank feeding as "non critical" in orchid culture (air- and water management are). Orchids, in general, have more dilute "sap", suggesting a lower demand for the solute ions. Paphs, as I have learned here, are on even the low end of the orchid spectrum when it comes to nutrient demand. While "tweaking" a nutrition program to the species level might result in optimizing everything, it seems to me that if you provide "enough" of everything (macro, minor, and micro), and not "too much" of anything, your plants will do fine.


----------



## NYEric (Dec 2, 2010)

Eric Muehlbauer said:


> Eric....Pot Store is what we call the hydroponics store on Horace Harding in Flushing. Somehow I don't think that orchid growers are the primary customers at a hydroponics store....



Oh. i was wondering if sloth [weed induced] became legal while I was sleeping that night!


----------



## Carper (Dec 2, 2010)

Assuming Ray, that foliar feeding is not much good, you need then to promote root growth. What would be your approach with this and what products do you use?

Gary
UK


----------



## Eric Muehlbauer (Dec 2, 2010)

I've only heard of foliar feeding with paphs. I had read that the stomata are always open in paphs...which would make foliar feeding seem sensible. That said, I have never done it. Sounds messy to me, since I grow in my home. Maybe it would be more practical in a greenhouse.


----------



## TyroneGenade (Dec 3, 2010)

Ray said:


> In my opinion, foliar feeding of orchids is - relatively speaking - a waste of time.



I was told the same by Mike Byren, the orchid guru in the local club. He even suggested that the ferts just trickle down eventually to the roots and that is what foliar feeding "looks like" it works. 

Never the less, a friend is reporting miraculous results with his Neos using Kelpak and I am eager to see if its true. I will experiment on my Paphs as well while I'm on it... Nothing ventured nothing gained. (And being a bad waterer I will flush the pots clean of ferts on a too regular basis!)


----------



## Rick (Dec 3, 2010)

Eric Muehlbauer said:


> I've only heard of foliar feeding with paphs. I had read that the stomata are always open in paphs...which would make foliar feeding seem sensible. That said, I have never done it. Sounds messy to me, since I grow in my home. Maybe it would be more practical in a greenhouse.



I have a lot of mounted orchids that just get sprayed. Some have lots of exposed roots and some have more leaves than roots, but everything is fair game when watering. These would probably not be practical in your house.

I spend very little time trying to avoid the upper foliage when watering my plants, and I don't always try to soak the pots. But when I first started playing with epsom salts, I was amazed as to how fast the leaves greened up with nothing more than some fast foliage sprays. The amount of material the plants need must be next to nothing to get the effects I've seen with just a small percent getting onto roots and moving up into plants in such short notice if foliar feeding did nothing.


----------



## Rick (Dec 3, 2010)

Eric Muehlbauer said:


> I had read that the stomata are always open in paphs...which would make foliar feeding seem sensible.



As long as the lights are on the stomata are open on all orchids.


----------



## Ray (Dec 3, 2010)

Eric, even with available stomata, I'd still bet that the percentage of uptake via the roots is far greater than that through leaves (hence my statement "relatively speaking..."), and I agree with you that I'd rather not deal with the mineral buildup on the leaves.

Gary:

Promoting root growth? Again, I'll go back to my feeling that a healthy plant is going to be at its "best", and to do that, keep the medium airy and moist, feed adequately, and make the plant comfortable.

I am not a big believer in "booster" products. Yes, the application of rooting hormones can be a benefit, especially if your culture is otherwise lacking, but without a doubt, the biggest boon to root growth I have seen is very old technology transferred to orchid growing: seedllng heat mats.

They were suggested to me as a way to get plants to "convert" more quickly from traditional culture to semi-hydroponics, and in that application (not specifically with paphs), I see plenty of new root growth within 2-3 weeks, as opposed to 6 or 8 without it. Since seeing that, I have expanded it to all repotting. I originally began with a 17W mat that fits nicely in a standard nursery tray, but ended up outfitting a bench in the greenhouse for transplants. They only boost the root zone temperature by 10°-15°F over ambient, but it seems to really add a lot.

Tyrone - Kelpak is a product made from the chemicals extracted from a cold-water kelp, and some of them have long been known to have root growth-stimulating properties, so why not? That doesn't mean that it has to be applied foliarly, does it?


----------



## TyroneGenade (Dec 3, 2010)

Ray said:


> Tyrone - Kelpak is a product made from the chemicals extracted from a cold-water kelp, and some of them have long been known to have root growth-stimulating properties, so why not? That doesn't mean that it has to be applied foliarly, does it?



No, it does not.


----------



## Ernie (Dec 3, 2010)

Ray said:


> Kelpak is a product made from the chemicals extracted from a cold-water kelp, and some of them have long been known to have root growth-stimulating properties, so why not? That doesn't mean that it has to be applied foliarly, does it?



Devil's advocate: if one has a plant with no root system or a compromised one, how would one use kelp extract to stimulate roots other than foliar? :evil:

I'm not saying foliar feeding works or doesn't- i honestly have no idea. I've seen magazine articles (not primary, peer reviewed literature) which say orchid stomata are always open, always closed during the day, they open and close as needed, etc... Alan Koch of Gold Country Orchids insists in his talks that foliar feeding is crucial in his success with catts- he emphasizes that foliar feeds to the leaf undersides is the only way to go. He also says chelated elements (ie those with EDTA, iron is commonly chelated) are too big to make it into stomata. 

Truth is, I don't think anyone knows for sure (do they??? please cite primary literature references), so the utility of foliar feeding is speculative. Shoot, orchids are so diverse one genus may do one thing and the next something different. We do know roots take up nutrients. Anyway, when we water, we usually water/fertilize the leaves as well as the pot. Just seems like an okay thing to do. 

I'll take my usual stance that... done in moderation with weak solutions it won't hurt. In this case, it may help some. As long as there's not mineral buildup on the leaves, I'd expect no harm. Would I rely on foliar feeding as the sole source for nutrient/supplement delivery? No. 

I think the adaptation of leaf structure to funnel water and nutrients to the center of the plant into a favorable drip zone is a super nifty thought. Makes sense functionally, but would be hard to test phylogenetically. Some orchids do "trash basket" their roots by sending them upwards (many Catasetums do this) to catch falling leaves etc which decompose to provide nutrients, no reason the leaves wouldn't serve a similar function... Shoot, plants in the yard seem to catch falling leaves and smaller acorns from the live oaks in the crown. Dang, we need another grad student to look at this...


----------



## gonewild (Dec 3, 2010)

For the sake of learning....



Ray said:


> Oh Tyrone... Now you've done it, and opened another can of worms.
> 
> (Hee Hee) I'll start:
> 
> In my opinion, foliar feeding of orchids is - relatively speaking - a waste of time.



In my opinion foliar feeding of most plants is beneficial when plants are in artificial growing conditions.



> As they have evolved with a "water retention" strategy:
> 1) Orchids don't have a lot of leaf stomata compared to terrestrial plants.



So if they have less ability to absorb nutrients then nutrients should be available more frequently.



> 2) Most of the stomata tend to be concentrated on the under-sides of the leaves.



And this effects foliar nutrient benefit how? If I foliar feed the undersides of leaves get wet.



> 3) Many orchids have a "waxy" layer on the leaves to further limit transpiration.



Do we know that this waxy coating prevents nutrient absorption? 
May a "bio" reverse osmosis membrane? 



> 4) CAM plants even close their stomata in the daytime (when we would most likely feed).



But nutrients remain on the leaf surface after the water evaporates off so they would be available at night.

I suspect that while there may be some - very limited - benefit to foliar feeding, what we are truly experiencing is fertilizer dripping off of the leaves onto the root system. One plant biologist even told me that plants with "fan structures" are _designed_ to channel liquids down to their centers, where the droplets will coalesce and drip to the roots.

Many (most, all?) orchids with fans have leaves that hang down and actually divert water from the roots. Also most orchids that I have see growing naturally on tree trunks tend to have more of the root system growing UPWARDS and away from the plant base. 



> Back to the original fertilizer question - I rank feeding as "non critical" in orchid culture (air- and water management are).



I bet growers like Matsui that produce plants by the millions in very short time would disagree with this concept!

Feeding may be something that is secondary if your main goal is to just keep a plant healthy, alive and growing along at a retirement pace. But if you want the the plant to grow at the fastest possible rate and be it the best of physical condition then you must provide all the nutrients it needs to put on bulk.



> Orchids, in general, have more dilute "sap", suggesting a lower demand for the solute ions.



Or does this suggest a higher demand for a more constant supply?



> Paphs, as I have learned here, are on even the low end of the orchid spectrum when it comes to nutrient demand.



Low demand compared to what, faster growing species? Because the appear to grow slow does not mean they require less nutrient availability. 
Or does it?



> While "tweaking" a nutrition program to the species level might result in optimizing everything, it seems to me that if you provide "enough" of everything (macro, minor, and micro), and not "too much" of anything, your plants will do fine.



Doesn't this paragraph define the MSU fertilizer formula?

For the record I don't "foliar feed". But in reality I always foliar feed because when I do water with or without fertilizer I always wet the leaves.


----------



## gonewild (Dec 3, 2010)

Ernie said:


> I think the adaptation of leaf structure to funnel water and nutrients to the center of the plant into a favorable drip zone is a super nifty thought. Makes sense functionally, but would be hard to test phylogenetically. Some orchids do "trash basket" their roots by sending them upwards (many Catasetums do this) to catch falling leaves etc which decompose to provide nutrients, no reason the leaves wouldn't serve a similar function... Shoot, plants in the yard seem to catch falling leaves and smaller acorns from the live oaks in the crown. Dang, we need another grad student to look at this...



Do you have any extra slow release acorns?
Hmmm....wait maybe the acorn is there to eat the plant?

I think actually the roots of plants like the Catasetums that grow upwards are actualy doing so for support rather than seeking nutrients. The plants can get more nutrients from bird poop than falling leaves. 

And since a plants leaves are a better net for falling bird poop than it's roots are that sould put a point on the side of foliar feeding.


----------



## Ernie (Dec 3, 2010)

gonewild said:


> Do you have any extra slow release acorns?
> Hmmm....wait maybe the acorn is there to eat the plant?
> 
> I think actually the roots of plants like the Catasetums that grow upwards are actualy doing so for support rather than seeking nutrients. The plants can get more nutrients from bird poop than falling leaves.
> ...



RE catasetums- i remember, while researching for a judging project, coming across a picture of a massive Catasetum in the jungle and it was obvious it was trash basketing. The root system was huge and full of all kinds of things. If it was in the US, it woulda had Coke cans, Big Mac wrappers, and cigarette butts in it. Roots radiated out in all directions and the plant might have been at the top of a stump??? I'll have to try to track it down, but it might have been in a book (gasp!) that I don't own. Anyway, I saw some home-grown hybrids doing that down here at the Lakeland show this September too. 

As far as where crowns aim in wild plants, I'm sure one would find a broad range depending on species and where it is growing. Too many to generalize. No reason we can't use funneling to our advantage though. On the converse, I've had massive plants suddenly go downhill later to discover a massive root system perfectly dry because all the leaves were carrying water away from the pot and too much media being covered by leaves. 

Anyway, I think we agree.


----------



## Rick (Dec 3, 2010)

I'm curious as to how many of us growers water/feed there plants strictly by adding water to the pots or root zone reservoirs (as for hydro or Semi hydroponic systems) without getting any water on the leaves. If you are misting foliage, then are you using purified/RO water? Because there are nutrients of concern in all non purified surface waters, and we still wouldn't have a controled experiment of foot vs leaf uptake of nutrients. 

Most growers, including myself (at least in GH's) tend to just spray the whole world, and realy couldn't define foliar only feeding regimes. But unless you have your whole collection in a single source watering trough, it would take way too long to carefully water individual pots without getting leaves wet.

So unless I'm not doing true foliar feeding by flipping plants upside down to get the bottoms of leaves wet, then who will ever know whether its the stuff going in through the leaves or through the roots?

I've seen some great plants grown SH, but I have not seen a unversal success to SH grown plants, and the FCC's are dominated by "traditional" splash fed/watered plants. So its apparent that feeding isn't the whole story, and there seems to be too many differences between species to generalize for perfection.


----------



## gonewild (Dec 3, 2010)

Ernie said:


> RE catasetums- i remember, while researching for a judging project, coming across a picture of a massive Catasetum in the jungle and it was obvious it was trash basketing. The root system was huge and full of all kinds of things. If it was in the US, it woulda had Coke cans, Big Mac wrappers, and cigarette butts in it. Roots radiated out in all directions and the plant might have been at the top of a stump??? I'll have to try to track it down, but it might have been in a book (gasp!) that I don't own. Anyway, I saw some home-grown hybrids doing that down here at the Lakeland show this September too.
> 
> As far as where crowns aim in wild plants, I'm sure one would find a broad range depending on species and where it is growing. Too many to generalize. No reason we can't use funneling to our advantage though. On the converse, I've had massive plants suddenly go downhill later to discover a massive root system perfectly dry because all the leaves were carrying water away from the pot and too much media being covered by leaves.
> 
> Anyway, I think we agree.



Yes we agree. Whether nutrients are applied to the leaves, stems, or roots they benefit the plant.

The Catasetums I'm familiar with in Peru generally hosted ant nests. The ants built some structure around the plant base and roots creating a ball. The little devils made it pretty impossible to collect a plant! This was mainly with plants that grew in a limb crotch and the plants tended to grow more upright than hanging because of the ant support. Maybe the ants are symbiotic by providing protection to the plants or maybe the ants provide some form of nutrient assist for the roots, I doubt anyone has studied it. Other Catasetum plants that grew on the sides of tree trunks tended to hang downward with the roots growing up the trunk. 

The roots grow upwards because that is the direction needed for support. If the roots grew down the weight of the plant would just peel the roots off the trunk and all would fall down.


----------



## gonewild (Dec 3, 2010)

Rick said:


> I'm curious as to how many of us growers water/feed there plants strictly by adding water to the pots or root zone reservoirs (as for hydro or Semi hydroponic systems) without getting any water on the leaves. If you are misting foliage, then are you using purified/RO water? Because there are nutrients of concern in all non purified surface waters, and we still wouldn't have a controled experiment of foot vs leaf uptake of nutrients.
> 
> Most growers, including myself (at least in GH's) tend to just spray the whole world, and realy couldn't define foliar only feeding regimes. But unless you have your whole collection in a single source watering trough, it would take way too long to carefully water individual pots without getting leaves wet.
> 
> ...




Yep, we will never really know the answer about foliar feed vs root feed and if either or is more important.

It is obvious plants like a shower.... just take a walk through the forest after a rain....everyone is happy. 

Remember that rain is not pure water and is often (maybe always) supplemented with nutrients from the atmosphere.


----------



## tim (Dec 3, 2010)

These are interesting questions - using a Stanford login to see some of the other articles results in some gems with regard to foliar feeding (I'm quoting here in some cases because I believe the pdfs are not accessible unless you have a university login - please contact me if you want more info)....

foliar fert result in Phals and Mokara:
http://www.actahort.org/books/878/878_37.htm

foliar feeding in mangos:
http://agris.fao.org/agris-search/search/display.do?f=1986/PH/PH86011.xml;PH8510716

fertilizer in Vanda Ms. Joaquim (click on the pdf at the bottom - among others, it intimates that high K and P are essential in making larger flowers - that flower size was only affected by K and P).
http://scholarspace.manoa.hawaii.edu/handle/10125/5985

Foliar fertilizer use developed for use in cereal crops - Gooding MJ, Davies WP (1992) Foliar urea fertilization of cereals: a review. Fert Res 32:209–222

"The strong competition existing for nitrogen in epiphytic ecosystems could have allowed plants to develop the capacity to absorb nitrogen in a more or less reduced form, such as ammonium, urea or other organic forms, instead of nitrate, as most terrestrial tropical plants. Moreover, it has been shown that for certain epiphytic bromeliads, urea absorbed by foliar trichomes represents one of the principal sources of nitrogen " - Endres L, Mercier H (2001) Influence of nitrogen forms on the growth and nitrogen metabolism of bromeliads. J Plant Nut 24:29–42

lots and lots more...try google scholar for "foliar fertilizer orchid"

For more on fertilizer from Floricultura, have a look at page four of this (but understand they grow a limited type of plant - mostly Deperle-types)
http://www.floricultura.nl/Upload/Bestanden/TCENG/433719_09-Paphiopedilum-ENG.pdf

I would have to disagree that fertilizer for orchids is not very important. Perhaps better to say not very important to the home grower. Every single major producer of orchids has a definitive fertilizing schedule - in many cases if the nursery is licensed by the state a full fertilization scheme has to be submitted and approved before a business license is issued. Since chemistry is often the thing understood least by hobbyists (and I'm including myself here for sure), it is often the most ignored...that doesn't mean it is unimportant, just that it is poorly understood.

I use Peters 20-20-20 with cal-mag and 17-7-17 Nutricote. I fertilize dilutely and don't measure EC and therefore I am not as careful or technical as I should, and consequently I get sub-optimal growth.


----------



## Kavanaru (Dec 3, 2010)

gonewild said:


> I think actually the roots of plants like the Catasetums that grow upwards are actualy doing so for support rather than seeking nutrients.


Ok, I stay out of the rest of the discussion on nutrition of Paph and Co, but regarding this one, I have to give my two cents and agree that Catasetum do produce this aerial spikes (they are spikes more than roots - yes, I know, they are roots, but they are hard as spikes.. that's what I mean) to catch fallen leave and other falling material. However, Catasetum (by the way, not a CAM genus, but C3!) are very heavy feeders and are adapted to a medium where most orchdis would not survive very long: rotten wood and organic compounds. They need to absorb as much mutrients (and water) as possible in a very short period of time. These kind of "collecting roots" are more evident in those species growing under very hard conditions: periods of heavy rain but drying out very quick, and very dry and hot periods. Species growing in more regular conditions do not tend to produce this kind of root. As well, species which normally produce this kind of roots, do not produce them very often if they have a steady and normally high supply of nutrient (e.g. artificial culture in pots - in many years growing Cataetum, I have had "collecting" roots only in the plants grown on the trees and left to the natural conditions!).
Normally, Catasetum gets support from the "normal" roots, which extend on teh surface ot the supporting wood, but also go inside the wood for up to 30 cm (at leats the ones I have seen in the wild, and would not be surprise if they can be longer), literally anchoring the plants in the decaying trunk!


----------



## Kavanaru (Dec 3, 2010)

gonewild said:


> The Catasetums I'm familiar with in Peru generally hosted ant nests. The ants built some structure around the plant base and roots creating a ball. The little devils made it pretty impossible to collect a plant! This was mainly with plants that grew in a limb crotch and the plants tended to grow more upright than hanging because of the ant support. Maybe the ants are symbiotic by providing protection to the plants or maybe the ants provide some form of nutrient assist for the roots, I doubt anyone has studied it. Other Catasetum plants that grew on the sides of tree trunks tended to hang downward with the roots growing up the trunk.



Lance, indeed there are studies about these symbiosis. Ants get a supporting structure for their nests and until certain extent protection from the plant, as well as other supplies, while the Catasetum benefits of extra nutrient from decaying "ant-nest" material, increased humidy around the roots, ants protetion and so on.. 

as per the hanging Catasetum, are you sure they were the same species? there are few Catasetum species which normally (in some species alweays) grow hanging... I know Cataseum which associates to ants in Venezuela, and those individual plants without ants (yes, not all individuasl succeed with the ants) also grow upwards... on the other hand, Catasetum longifolium, a hanging speciues, sometimes associates with ants or termites, and still grows hanging.




gonewild said:


> The roots grow upwards because that is the direction needed for support. If the roots grew down the weight of the plant would just peel the roots off the trunk and all would fall down.



see my previous post where I explain about the roots growing into the wood.... Those are the roots that give support to the plants. The "collecting" roots, are very fine and do not attach to anthing aroung, therefore being "useless" when it refers to holding or attaching the plant to the trunk.


----------



## cnycharles (Dec 3, 2010)

interesting discussion. I read a paper and mentioned it here maybe a year ago that showed that nutrients from sea water 'fog' was one of the main sources of nitrogen in cloud forests in south or central america; cold and warm water sources mixing created the condition, and the fog moving over the plants supplied them with an amazing amount of fertilizer. also it's supposed that rain from lightning storms contains nitrogen or other nutrients created by the lightning which washes down in the rain. so besides bird poop and decaying plants there are possible sources of nutrients being made available even if it isn't raining (even in the 'pure' dew(maybe)).

also, it was mentioned that plants that had leaf fans were noticed to have roots that grew up a tree; i'd suggest that this may not an adaptation to collect water running off of leaves but pure physics in that roots purely growing down from a plant on a tree likely wouldn't be able to hold up to the strain of keeping a plant on a tree, without ripping off. roots growing up the tree would be more likely to endure the strain and keep the plant on the tree

I think yin tung wang did research with foliar feeding and phal hybrids and showed that foliar feeding was very helpful; though it's almost 11pm and since what I read was a while ago I could be mixing a few different things together (and phals normally have very waxy leaves which seemingly would repel water and nutrients). of course normally during wet seasons phals can get inundated with water/rain, so the waxiness could be to prevent the rain from leaching out what's inside, or just protect the plants from the pounding of rain

ray, it's interesting that you mention here previously about s/h roots doing better when they are placed on a heat mat; i've told people that s/h could work for them but I didn't think it worked well for me because conditions would be too cool for me in winter but if they could warm up the roots the whole plant would be warmer and do better. my first growing shelf when I moved to this apartment had heating coils from an aquarium heater/bucket of water, which was piped underneath the shelf where the plants were. I think they liked it, but I unfortunately collected more plants than I had space for on that shelf so I ended up removing it  though I did have the idea about using a small tank water heater to pipe warm water into each shelf, kind of like the flexible tubing benches used to warm the air underneath plants. i'll bet this would work well for s/h plants/pots (really going off on a tangent)


----------



## Rick (Dec 3, 2010)

I have a handful of Gongora that also do the "trash basket" roots as well as the thick standard roots.

Mine are in hanging baskets of moss so I do get to see a lot of roots. Most are about an 1/8" diameter and weave around in the moss and basket. But then there's a bunch that poke straight up from the surface of the basket that are hard and about 1/16 in diameter. Very spiky too.

Between the Gongora and Coryanthes, they seem to be real ant magnets in my GH:sob:


----------



## Erythrone (Dec 3, 2010)

From the book 'The physiology of tropical orchds in relation to the industry-Second Edition (2004).

"The controversy of adotping eigher foliar or root feeding of fertilisers remains unresolved. This is attributed to the fact that we have little information on the efficiency of mineral utake using the 2 methods of application".

An interesting point about organic fetriliser: "There is evidence to indicate that a combination of organic and inorganic fertilisers gives better orchids growth"


----------



## TyroneGenade (Dec 4, 2010)

gonewild said:


> Remember that rain is not pure water and is often (maybe always) supplemented with nutrients from the atmosphere.



Very good point. Rain condenses on dust particles (e.g. in Florida the bulk of the dust comes from the iron rich red soil Sahara desert). Living downwind from an industrial complex is probably not that great for your orchids.



tim said:


> "...Moreover, it has been shown that for certain epiphytic bromeliads, urea absorbed by foliar trichomes represents one of the principal sources of nitrogen " - Endres L, Mercier H (2001) Influence of nitrogen forms on the growth and nitrogen metabolism of bromeliads. J Plant Nut 24:29–42



I guess this backs up Lance's bird poop point. Bird poop is full of urea.

This is the best kettle of worms I have opened up in a long while oke: Whatever the reality of foliar vs root feeding it seems any plain old balanced NPK fert will work just as well as anything fancy if fed in moderation. This is particularly irritating as I bought a bottle of Kalpak yesterday (and am now spraying it about like a mad man), passing over the tub of 18:18:18 orchid bloom booster. :sob:


----------



## gonewild (Dec 4, 2010)

Kavanaru said:


> as per the hanging Catasetum, are you sure they were the same species?



No not sure about the species. Plants were not always blooming and there was several species that probably are undescribed. I collected what I think to be 9 different species and there were a lot more that were not collected. 
But I am relatively sure that some of the species were growing with both habits. Some of the plants that were hanging after being collected and planted on tree branches or crotches in the garden grew more upright with the root mass effect. 

t


> here are few Catasetum species which normally (in some species alweays) grow hanging...



I saw Catasetum longifolium growing on palms and hanging maybe 5' long. Very cool plant. I've seen it with both root structure types.
What i saw was as the palm grows and sheds it's fronds the Catasetums fall if the roots were growing in the mass style were if the plant actually attaches to the bare trunk and grows the support type roots then the plant is secure for what could be the life of the palm. Now another point of interest is that these two situations involve 2 different palm species. The Catasetum that had mass roots and fell from the tree was growing in a Shapaja palm in an open field. The Catasetum that was secure on the trunk with long roots was growing on an Aguaje palm in a lake. Neither plant would receive much fertility from falling leaves as there was no upper canopy. The plant growing on the Shapaja would endure long dry periods where the plant on the Aguaje would have a constant humidity from the water below.

What this has do with foliar feed i don't know but I bet there is something?




> I know Cataseum which associates to ants in Venezuela, and those individual plants without ants (yes, not all individuasl succeed with the ants) also grow upwards... on the other hand, Catasetum longifolium, a hanging speciues, sometimes associates with ants or termites, and still grows hanging.



Yes and it does produce both types of root structures.



> see my previous post where I explain about the roots growing into the wood.... Those are the roots that give support to the plants. The "collecting" roots, are very fine and do not attach to anthing aroung, therefore being "useless" when it refers to holding or attaching the plant to the trunk.



The roots would penetrate the decaying wood just like growing in a pot of fir bark. But when the plant grows on decaying wood it is somewhat like a suicide mission.... soon the support tree will fall away and the orchid will die.


----------



## gonewild (Dec 4, 2010)

cnycharles said:


> (and phals normally have very waxy leaves which seemingly would repel water and nutrients). of course normally during wet seasons phals can get inundated with water/rain, so the waxiness could be to prevent the rain from leaching out what's inside, or just protect the plants from the pounding of rain



As you say the waxy leaves would seemingly be to repel water. But do we really know what the waxy coating is really about? Does it have a function like maybe to absorb nutrients from the air or leaf surface?


----------



## Kavanaru (Dec 4, 2010)

gonewild said:


> The roots would penetrate the decaying wood just like growing in a pot of fir bark. But when the plant grows on decaying wood it is somewhat like a suicide mission.... soon the support tree will fall away and the orchid will die.



yeap! and that's normally the fate of Catasetumin the wild... therefore they grow pretty quick (you can have a blooming plant from seeds in less than 3 years sometimes!) and produce the highest numbers of seeds in the orchid's world! Other Catasetinae, like some Cycnoches and Mormodes species have even shorter lifes than catasetum in the wild for the very same reason. It is not rare to find large Catasetinae plants laying on the ground, after they fell down... and Of course, there are some species that last longer and or are adapted tomore stable substrates, e.g. the terrestrial species...


----------



## gonewild (Dec 4, 2010)

TyroneGenade said:


> Whatever the reality of foliar vs root feeding it seems any plain old balanced NPK fert will work just as well as anything fancy if fed in moderation. This is particularly irritating as I bought a bottle of Kalpak yesterday (and am now spraying it about like a mad man), passing over the tub of 18:18:18 orchid bloom booster. :sob:



One thing I have never see in all the time I have spent walking through orchid habitat is kelp extract falling from the sky. oke:


----------



## Ernie (Dec 4, 2010)

gonewild said:


> One thing I have never see in all the time I have spent walking through orchid habitat is kelp extract falling from the sky. oke:



And has the rain or dew ever been blue with Peter's 20-20-20??? oke:

We do see lizard poop on our orchid leaves down here.


----------



## gonewild (Dec 4, 2010)

Ernie said:


> And has the rain or dew ever been blue with Peter's 20-20-20??? oke:



It's raining blue water right now outside here. But somehow I don't think it is from Peter?



> We do see lizard poop on our orchid leaves down here.



Bird poop, lizard poop, frog poop......... giving it some thought maybe the most important poop for plants is from insects. Anyone know the nutrient content of insect poop?


----------



## Rick (Dec 4, 2010)

gonewild said:


> It's raining blue water right now outside here. But somehow I don't think it is from Peter?
> 
> 
> 
> Bird poop, lizard poop, frog poop......... giving it some thought maybe the most important poop for plants is from insects. Anyone know the nutrient content of insect poop?



Probably depends on what kind of insects and what they are eating.oke: I think you forgot bat poop (which is like concentrated digested insects).


----------



## Eric Muehlbauer (Dec 4, 2010)

I would think that insect poop (which has uric acid, like bird and lizard poop) would be in tiny particles more easily broken down...and a lot of insects could lead to a lot of very tiny turds more evenly distributed.


----------



## gonewild (Dec 4, 2010)

Eric Muehlbauer said:


> I would think that insect poop (which has uric acid, like bird and lizard poop) would be in tiny particles more easily broken down...and a lot of insects could lead to a lot of very tiny turds more evenly distributed.



You are right... insect poop is extra tiny!

I found a study done on spider poop and bromeliads.....
http://departments.oxy.edu/biology/gnorth/250/tank-bromeliad-spiders.pdf

It is about bromeliads and not orchids but does pertain to some things mentioned in this thread. They found that spider poop accounts for a high percentage of the plants nutrient source. The spider poop has molecules smaller than amino acids and so probably enter the leaf easier.... Maybe true for orchids as well?

Here is one paragraph from the study..

_Although absorptive trichomes are more abundant on
the leaves of B. balansae than on other terrestrial, rootbased
bromeliads, and can absorb minerals (Benzing
and Burt 1970), they are probably unable to absorb
amino acids (Benzing et al. 1976). Because the N
compounds excreted by P. chapoda spiders (e.g.,
guanine) are simpler than some amino acids, they might
be incorporated directly through the trichomes. In
addition, the larger amino acids and other complex
organic molecules (e.g., insect carcass) may possibly be
mineralized by bacteria (and perhaps other microorganisms)
found on the leaves and roots of B. balansae._


----------



## gonewild (Dec 4, 2010)

Rick said:


> Probably depends on what kind of insects and what they are eating.oke: I think you forgot bat poop (which is like concentrated digested insects).



Do bats poop while they are flying through the forest?


----------



## Kavanaru (Dec 5, 2010)

gonewild said:


> Do bats poop while they are flying through the forest?



At least they poop when they enter the houses in the tropics to catch insects, which are flying around the lamps. Therefore I would assume they also poop when flying through the forest...


----------



## goldenrose (Dec 5, 2010)

Why not!
I'm really enjoying this thread! :rollhappy:


----------



## gonewild (Dec 5, 2010)

Kavanaru said:


> At least they poop when they enter the houses in the tropics to catch insects, which are flying around the lamps. Therefore I would assume they also poop when flying through the forest...




Yes the bats we have here at the warehouse all poop when they leave their roost. Well, maybe they pee when they leave the roost? Something falls! But I don't remember being dropped on while they are flying around catching bugs. But they mostly must poop in bed so as to fill up the bat cave with guano. Hmm... maybe bat pee is even a better foliar fertilizer?

Now if you saw some bat poop land on an orchid plant in your house we can document that bat poop is a natural foliar feed for orchids.
We may be on to something here...:clap:


----------



## Kavanaru (Dec 5, 2010)

not really bat poop landing on orchids, but landing on the table and furniture of my sister's house... and no, the bats do not sleep in the house  they just fly in during the night to catch the bugs flying around the lamps during the rainy season... so, I think that if they do it in my sister's house, they can do it anywhere else too


----------



## Rick (Dec 5, 2010)

Bat's often "lighten their load" just before takeoff for the evening, but given the amount they put down, they probably crap all over the place as they fly around. Bats don't always spend the days in big cave colonies either. I find them under the bark of old dead trees too.

I think I once heard that guanine (the amino acid in spider poop) is also a biggy in bat poop.

Actually I think the odds of fertilizing orchids by anything randomly flying or crawling around, with direct hits to leaves is pretty low. However, the amount of higher life forms living on trees (or in the soils) in the tropics is probably impressive. It always seems like everything is constantly in competition in all 3 dimensions for nutrition in a rain forest. As a gross generalization, orchids seem to be on the fringe to glean whatever they can from whatever media is available (air, rain, compost). I think the whole symbiosis thing with fungi contests to a really tight nutrient budget wherever orchids are found.

Given the (relatively) successful orchid collections that I'm aware of where NO conscious fertilizing is going on I would go out on a limb to say that a big part of peoples problems with nutrition are due to excesses of fertilizer causing over doses of certain constituents with antagonism as a result.

In the quest for perfection, I'm sure we can push better growth of plants than what they would do in the wild, but recently we've had a few posts that seem to indicate (mostly for the multifloral species) that some species eluding our best GH efforts.


----------



## Brabantia (Dec 7, 2010)

Thank you all for your interventions on a vast subject that still fascinates the orchid growers.


----------



## Ray (Dec 7, 2010)

Lance, going back to your original post, the only thing I could disagree with is the statement that dried fertilizer on the leaf surface would be available to CAM plants when the stomata open. It is my understanding that plants can only absorb minerals in solution. How would dried material be transported into the stomata, anyway?

Also, my statement that fertilizer is "less critical" than air and water was not meant to imply for a second that it wasn't important, just that water and gas exchange are "life and death" level, while nutrition is a factor in how well the plant grows. Surely we have all heard of someone's grandmother whose phals bloom profusely, and she has never fertilized them...

The "low sap concentration" potentially requiring a low, but more constant supply of nutrition is not something I had connected before, but I like the concept, and I may have experienced it first hand (see my response to Rick, below).

To Rick's query about feeding method and whether we are doing foliar and roots-only feeding simultaneously - I use the "fire hose" technique. When I water (which always includes fertilizer) everything in the greenhouse gets thoroughly soaked (even me) with essentially no surface unwetted. However, years ago when I ran a six-month, daily watering experiment to see if a plant established in S/H culture could be overwatered, the pots (150 each Phalaenopsis Lemforde White Beauty and Oncidium Sharry Baby) were fed by individual hoses from a manifold, so the foliage did not get wet. After six months, the plants were larger than the ones I hand watered "as needed". I have no doubt it was due to the more-or-less constant supply of "target" solution chemistry - i.e., more mass of prime nutrition - and I know it does not address whether that PLUS foliar might have been better, but it does show that roots-only feeding certainly can be adequate, and I'll be damned if I'm going to risk that much crown rot!


----------



## gonewild (Dec 7, 2010)

Ray said:


> Lance, going back to your original post, the only thing I could disagree with is the statement that dried fertilizer on the leaf surface would be available to CAM plants when the stomata open. It is my understanding that plants can only absorb minerals in solution. How would dried material be transported into the stomata, anyway?



At night moisture condenses on the leaf surface and re-hydrates the dried nutrient salts. Then the nutrients are once again available for the leaf to take in. It does not require visible moisture to have this work and in situations where there is no moisture on the leaf surface then the plants are not likely to be in an actively growing state anyway.



> Also, my statement that fertilizer is "less critical" than air and water was not meant to imply for a second that it wasn't important, just that water and gas exchange are "life and death" level, while nutrition is a factor in how well the plant grows. Surely we have all heard of someone's grandmother whose phals bloom profusely, and she has never fertilized them...



Everyone knows granny has bats in her bellfry!



> The "low sap concentration" potentially requiring a low, but more constant supply of nutrition is not something I had connected before, but I like the concept, and I may have experienced it first hand (see my response to Rick, below).
> 
> To Rick's query about feeding method and whether we are doing foliar and roots-only feeding simultaneously - I use the "fire hose" technique. When I water (which always includes fertilizer) everything in the greenhouse gets thoroughly soaked (even me) with essentially no surface unwetted. However, years ago when I ran a six-month, daily watering experiment to see if a plant established in S/H culture could be overwatered, the pots (150 each Phalaenopsis Lemforde White Beauty and Oncidium Sharry Baby) were fed by individual hoses from a manifold, so the foliage did not get wet. After six months, the plants were larger than the ones I hand watered "as needed". I have no doubt it was due to the more-or-less constant supply of "target" solution chemistry - i.e., more mass of prime nutrition - and I know it does not address whether that PLUS foliar might have been better, but it does show that roots-only feeding certainly can be adequate, and I'll be damned if I'm going to risk that much crown rot!



I don't understand your statement about the risk of crown rot.... you said you water like a fire hose? You know crown rot is not caused by overhead watering or getting the foliage wet. As long as you have adequate air movement and proper environmental conditions crown rot is not an issue having to do with irrigation techniques, I think you eluded to that eariler.


----------



## Rick (Dec 7, 2010)

I think there could be a lot said for constant/frequent low dose of target nutruients.

Even witht the "fire hose" technique I've been using for years, I've noticed some pretty big improvements when I started adding back a percentage of well water with the RO or the frequent small spikes of Epsom salts between the weekly feeding regime.

Since I know there is a dash of phophate and potassium in my well water (no measurable nitrogen), I am now giving a daily, very low dose of Ca, Mg, Cl, SO4, PO5, K, and Fe with the daily mistings (whether or not it trickles down to the roots). The sporadic Epsom salt spikes would alter the Ca/Mg ratio on most of the sunny days.

Now to account for top dresses or mix additives of bone meal or oyster shell.......


----------



## TyroneGenade (Dec 9, 2010)

A new kettle of worms:

Any thoughts on using aquarium water?

The local municipal water is very soft. To grow aquarium plants we have to add Ca, Mg and K to it to get the carbonate hardness to 72 ppm and general hardness to 80 ppm. My nitrate levels are between 5 and 20 ppm and I guess phosphate is in the same ball park.

Any thoughts on using the waste water for the orchids?


----------



## Ernie (Dec 9, 2010)

TyroneGenade said:


> Any thoughts on using the waste water for the orchids?



We use it sometimes on orchids. Most of it goes on tomatoes, Musa (banana), dracaena, and elephant ears just because of proximity. Have noticed no ill effects. If you add aquarium salt (non-iodized table salt), as some recommend, of course don't put it on your orchids.


----------



## Ray (Dec 9, 2010)

gonewild said:


> At night moisture condenses on the leaf surface and re-hydrates the dried nutrient salts. Then the nutrients are once again available for the leaf to take in.


 I thought you might throw that qualifier in there.



gonewild said:


> I don't understand your statement about the risk of crown rot.... you said you water like a fire hose? You know crown rot is not caused by overhead watering or getting the foliage wet. As long as you have adequate air movement and proper environmental conditions crown rot is not an issue having to do with irrigation techniques, I think you eluded to that eariler.


1) I made that comment because it seemed reasonable to me that SOME TIME during any 6-month period, the conditions might not be favorable for sufficient evaporation - increasing the risk of such rots.

2) What did I do to deserve you picking on me like this?


----------



## gonewild (Dec 9, 2010)

Ray said:


> I thought you might throw that qualifier in there.
> 
> 1) I made that comment because it seemed reasonable to me that SOME TIME during any 6-month period, the conditions might not be favorable for sufficient evaporation - increasing the risk of such rots.
> 
> 2) What did I do to deserve you picking on me like this?



Sorry Ray I did not know I was picking on you? Not my intention at all.
I questioned what you said because I thought you said you watered overhead and then implied that you did not want to risk crown rot by watering overhead. So I just wanted you to clarify what you wrote.

And yes there are always times when conditions might not be favorable for sufficient evaporation many times in a 6 month period. On those days the grower should not water overhead or even water at all since the plants probably won't use much water.

A simple rule to follow is to water overhead early in the day so that by 3:00 in the afternoon all the water on the foliage has dried up. That is a guideline I was told when I was a kid and it has worked well for a long time. Since I don't really like rules I generally will water later but want the foliage basically dry by 2 hours before dark. When I do water in the afternoon I always remember the old grower that told me the 3:00 rule and that causes me to evaluate just how wet I should get things. He was a short Frenchman that was retired from the Merchant Marines, always had a cigar hanging out of his mouth and his "orchid culture rules" always were shrouded in foul language that kept my mother at the other end of his greenhouse! Fond memories!

In a greenhouse you actually have less control over the drying times than in a room under lights. When I grew in greenhouses I pretty much followed the 3:00 rule because you never know what the next hour of natural weather might bring. Now that I am growing in a room under lights I don't care what the weather is outside, everyday is the same inside, misters go off at about 3:00 and the lights dry things out before dark. 

I will also add that back when we grew Phalaenopsis commercially in greenhouses I spent time every late afternoon or evening checking crowns in the plants for water. If there was water I blotted it out with a paper towel.
That is just part of growing, a job or oppertunity to visit and enjoy the plants. A person might figure it is easier and safer just to keep water off of the foliage but through years of experience and trial and error I learned that the plants grow better when you wet their leaves. I have no scientific paper to prove that, just what I have observed in my lifetime with orchids.

Bear in mind I was around to buy some on the first drip emitters when they came out. Little spaghetti tubes with lead weights. The sub irrigation worked great as a time saver but I did learn that the plants grew better with overhead watering. Then later along came ebb and flow. That worked too but even though it soaked the media better than drip the plants still grew better when they got their leaves wet.

Finally after living for some years in the tropical rainforest I have learned without any doubt that plants that come from a rainforest or wet environment really do like their showers. In fact every living thing in the rainforest is happy and excited after water falls on them.

Anyways Ray please don't think I was picking on you. I respect the things you have learned and appreciate hearing what you have to say.


----------



## cnycharles (Dec 9, 2010)

... about late watering rules, where I work we used to have management after us to not water after 1pm in the winter and dark/cool months; later on if it was cloudy they got after us if we watered after 11am! it was a big deal with excess humidity in the before and after winter times when it would get quite chilly and no sun, and they had turned down the heat a little to save money. with no venting as a result (would cause the heat to turn on), moisture from drips during the night from the roof condensation would stay on plants all day. cold drips and no sun definitely equals rots of many kinds!

the ellenbergers of e's orchid eden near rochester ny had a good technique to prevent crown rot or anything like that in their greenhouse; if anything looked like it might still have moisture hanging about later in the afternoon during times of higher disease pressure, they would spray a solution of physan to disinfect the water on the plants. things always looked very good, so that could be an option if things really needed watering and overhead but was risk of not drying off before the evening (heating and venting can do that, but of course now is getting more expen$ive!)


----------



## Erythrone (Dec 9, 2010)

Is Physan really safe for orchids?


----------



## cnycharles (Dec 9, 2010)

while I wouldn't use it on new seedlings or things like soft pleuros, the ellenbergers were using it successfully for lots of adult or hardened seedlings. you would have to read the label. an alternative is to use greenshield which is listed for use misting over cuttings or spraying on plants. I don't know what the difference between the two is, but reading the label would help to determine how to use it (or if physan is no longer listed for use on plants)


----------



## paphreek (Dec 9, 2010)

Thanks for the interesting discussion on watering. I've had a major concern with water sitting on leaves through the night as we've moved into November and December. My main heat is in floor, which is great for maintaining high humidity, but the leaves do not dry out before evening, which is at 4:30 PM, now, here in central Minnesota. I've taken to running the back up LP gas heater to dry things out. It seems to be working.

Since moving into the greenhouse in September, I've already noticed the Paphs perk up. I'm sure some of this is due to natural light, but, as Lance has mentioned, I also believe that the whole plant getting doused with water has helped, too. When I was growing in the house, the water was directed CAREFULLY to the media to avoid splashing water on carpets. The leaves rarely got wet. Plants grew and bloomed OK, but I never felt they were at their best.


----------



## gonewild (Dec 9, 2010)

Erythrone said:


> Is Physan really safe for orchids?



I have had a few bad experiences with Physan so I don't use it anymore.
I would still use it as a cure but not for prevention or substitute for more air circulation.


----------



## Ray (Dec 9, 2010)

Lance, I find your responses to be very thoughtful and astute - except for the last sentence in your reply to me. <insert grin here> Sorry for taking things wrong.

Re Physan: I have used it as an algae preventive on greenhouse glazing and drench pots. The labels says 2 teaspoons per gallon for rots, but I have seen the occasional damage in seedlings at that rate, so try to limit it to no more than one.

A commercial grower I know adds minute amounts to his irrigation tank - I think he mentioned it being in the neighborhood of a teaspoon per 20 gallons, or something like that - and commented that he has seen no botrytis, and a huge reduction in all rots.

As an experiment, I have added some to my fertilizer concentrate tank @ 1 tsp/5 gal to see if it will keep the bacterial sludge at bay (yes, but not completely - maybe I should increase that), and I can see no issues with the plants, since it is diluted 128:1 from there.


----------



## gonewild (Dec 9, 2010)

paphreek said:


> Thanks for the interesting discussion on watering. I've had a major concern with water sitting on leaves through the night as we've moved into November and December. My main heat is in floor, which is great for maintaining high humidity, but the leaves do not dry out before evening, which is at 4:30 PM, now, here in central Minnesota. I've taken to running the back up LP gas heater to dry things out. It seems to be working.



Unless your night temperature is lower than the plants optimum temperature water simply sitting "on the leaves" should not cause a problem. Water in the crowns of plants like Phals would be a problem however. Running your heater in late afternoon to help dry the water is a good practice. You can probably get the same results by running a strong fan without heat to dry off the foliage. 



> Since moving into the greenhouse in September, I've already noticed the Paphs perk up. I'm sure some of this is due to natural light, but, as Lance has mentioned, I also believe that the whole plant getting doused with water has helped, too. When I was growing in the house, the water was directed CAREFULLY to the media to avoid splashing water on carpets. The leaves rarely got wet. Plants grew and bloomed OK, but I never felt they were at their best.



Yes!


----------



## Erythrone (Dec 9, 2010)

gonewild said:


> I have had a few bad experiences with Physan so I don't use it anymore.
> I would still use it as a cure but not for prevention or substitute for more air circulation.




Me too. I prefer cinnamon extract. (hot water or alcool. Thanks, Ray, I took the idea on your web site)

But I use similar products (Quat) for cleening the room, but no longer on plant.


----------



## paphreek (Dec 9, 2010)

gonewild said:


> Unless your night temperature is lower than the plants optimum temperature water simply sitting "on the leaves" should not cause a problem. Water in the crowns of plants like Phals would be a problem however. Running your heater in late afternoon to help dry the water is a good practice. You can probably get the same results by running a strong fan without heat to dry off the foliage.



I have two, soon to be three HAF fans running constantly as well as a couple small fans in the corners that were temporary. I'm using an old pedestal fan until the other fan arrives. Even with all this air movement, things dry out slowly, now that the exhaust fans are shut down for the winter. I believe it is due to the high humidity caused by in floor heat evaporating water into the air, and poor air exchange due to the tightly sealed construction done to save heat. Do you think another method of air exchange would be helpful, and if so, any suggestions?


----------



## Erythrone (Dec 9, 2010)

Ray said:


> Lance, I find your responses to be very thoughtful and astute - except for the last sentence in your reply to me. <insert grin here> Sorry for taking things wrong.
> 
> Re Physan: I have used it as an algae preventive on greenhouse glazing and drench pots. The labels says 2 teaspoons per gallon for rots, but I have seen the occasional damage in seedlings at that rate, so try to limit it to no more than one.
> 
> ...




Thank you Ray. I forgot to say that I still use it for humidifier. I wonder if it can react with salts when mixed with fertilizer? And does it change pH?

Yes, I read that similar product (Kleengrow) are effective against Botrytis cinerea, fusarium (tomato, cucumber, etc) and other diseases. Efficient against some virus too.


----------



## gonewild (Dec 9, 2010)

paphreek said:


> I have two, soon to be three HAF fans running constantly as well as a couple small fans in the corners that were temporary. I'm using an old pedestal fan until the other fan arrives. Even with all this air movement, things dry out slowly, now that the exhaust fans are shut down for the winter. I believe it is due to the high humidity caused by in floor heat evaporating water into the air, and poor air exchange due to the tightly sealed construction done to save heat. Do you think another method of air exchange would be helpful, and if so, any suggestions?



What is the humidity of the outside air?
To dry the foliage you have two basic choices... raise the air temperature or lower the humidity of the air.
As odd as it sounds letting in some outside cold air might be cheaper than just running the heaters. If the humidity is lower outside bring in some of that air and the standing water will evaporate fast. Sometimes a tightly sealed greenhouse is not as efficient as one that leaks!


----------



## gonewild (Dec 9, 2010)

Ray said:


> Lance, I find your responses to be very thoughtful and astute - except for the last sentence in your reply to me. <insert grin here> Sorry for taking things wrong.



Ray, I will never intentionally write anything to pick on someone, to easy just to not write anything. But I will sure argue and discuss!


----------



## TyroneGenade (Dec 10, 2010)

paphreek said:


> I believe it is due to the high humidity caused by in floor heat evaporating water into the air, and poor air exchange due to the tightly sealed construction done to save heat. Do you think another method of air exchange would be helpful, and if so, any suggestions?



On solution would be to pump cold air (or rather water) through a radiator into the green house which can condense the humidity. There used to be an Atlanta Orchid Society Bulletin PDF online detailing how Alan Reinke used solar heating to heat his green house through winter, by pumping solar heated water through the green house and storing the heat in larger water barrels. This simple heat pump can be used to good effect to pump heat out as well. Instead of running the water through a solar heating array one simply runs it through the cold earth or through steel or copper pipes mounted in the cold air. Pumping water or some or other coolant through the outside pumps and then through a radiator you can dehumidify your air as well as collect lovely distilled water for your orchids.

The efficiency of the system will depend on the surface area available for heat exchange.


----------



## Brabantia (Dec 10, 2010)

I could not been able to imagine that my initial question would generate as many pages of discuss very interesting in addition.
But maybe the exact direction of my question was not well understood, English is not my native tongue.
I reformulate this one: It is well-known that an excess of nitrogen weakened the plants and makes them more sensitive to the fungal and bacterial diseases (large cells with thin walls). Can the ratio nitrogen / potassium modify this sensitivity to the diseases? As for example: a fertilyser 13/5/20 would it be more appropriate than a fertiliser13/4/15? Of course these fertilizers would be always used with Calcium and Magnesium in sufficiency. 
Thank you in advance for your comments which are always very spiked and appreciated.


----------



## Ernie (Dec 10, 2010)

Brabantia said:


> Can the ratio nitrogen / potassium modify this sensitivity to the diseases? As for example: a fertilyser 13/5/20 would it be more appropriate than a fertiliser13/4/15? Of course these fertilizers would be always used with Calcium and Magnesium in sufficiency.



Good refocus. Like I said, it's really hard to say, and difficult to test satisfactorily to generalize for "all orchids". However, I'd say that the difference between your two examples is nearly negligible and you will see little difference in a hobby collection using a 13-5-20 vs a 13-4-15.


----------



## gonewild (Dec 10, 2010)

The answer to your question is "*Yes*", the ratio nitrogen / potassium *can* modify this sensitivity to the diseases.

You are on the right path with what you are thinking. However the answer is very complex and can not be as simple as a percent formula.

The balance between all of the nutrients (minerals) is important. Not just between one or two. The MSU formula comes the closest to being perfect for a wide range of tropical plants growing in artificial media.

Yes if your Nitrogen level is to high compared to other nutrients the leaves grow fast and soft and become more prone to disease. But there are many factors that can influence the best fertilizer formula to use. Things like does your media hold nutrients or do the nutrients wash out quickly? Is your day and night temperature correct for the species you are growing? Is the light level strong or weak?

The MSU formula was not "invented" for orchids. It simply is a formula that works well because it provides a good ratio of minerals for orchids. The basic formula was being used by commercial growers long before MSU published their studies.


----------



## Brian Monk (Dec 10, 2010)

gonewild said:


> The answer to your question is "*Yes*", the ratio nitrogen / potassium *can* modify this sensitivity to the diseases.



Nitrogen/Phosphorous/Potassium ratios are also responsible for some aspects of "physiologic timing" in certain orchid species and genera. For example, phosphorous is often proposed as a "bloosom booster" in orchids, especially when applied inthe fall. I think we have all discovered that phosphorous is not as necessary in the quantities previously used in general orchid culture. But the ratio of phosphorous to nitrogen does change seasonally. With Cymbidiums, one can achieve a cessation of the growth phase of a plant, and an initiation of a resting/reproduction phase by increasing the phosphorous:nitrogen ratio for several days. This is a potentially devestating technique, as I have been told by several comercial growers that it can cause even very weak plants to bloom quite well, ensuring a severe decrease in the next years growth and often the death of the plant.


----------



## paphreek (Dec 10, 2010)

gonewild said:


> What is the humidity of the outside air?
> To dry the foliage you have two basic choices... raise the air temperature or lower the humidity of the air.
> As odd as it sounds letting in some outside cold air might be cheaper than just running the heaters. If the humidity is lower outside bring in some of that air and the standing water will evaporate fast. Sometimes a tightly sealed greenhouse is not as efficient as one that leaks!



Current temp is 16F


----------

