# Fertlizing and watering Paph. sanderianum



## The Orchid Boy (Sep 27, 2012)

I am wondering about fertlizing and watering paph. sanderianum. I read some article that Paph. sanderianum needs certain micro nutrients that other orchids don't need as much. The article also said something about iron-free fertilizers. I wondering how much and how often to fertilize. I have a 30-10-10 and a 6-30-30 fertilizer. 

Should I water with hard well water or soft rain water? Should I add lime or oyster shell to the mix? 

And one more question about potting: can I use a mix I make for my other paphs of 3 parts sphagnum moss, 2 parts medium bark, and 1 or .5 pats charcoal? I use sphagnum moss in every single mix I make for all of my orchids and my phals are potted in pure sphagnum moss. I have trouble keeping them water enough in a bark mixture under my 4 tube T5 lights.

Thanks.


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## Rick (Sep 27, 2012)

I think you should go through the threads on basket culture and K lite.


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## ehanes7612 (Sep 27, 2012)

i grow and bloom them pretty well, i have soft water looming around 6.5 pH, and they tend to like to be a little wetter than most multi's. i have found a variety of mixes work for them..i use a low K diet now although when i used a higher K diet they grew just fine..all in all they seem a lot more forgiving than a lot of paphs..actually, some of the hybrids can be less forgiving than the species....but they do prefer high humidity too


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## The Orchid Boy (Sep 27, 2012)

Is high humidity absolutely necessary? I know the higher the humidity, the longer the petals. My humidity ranges from 40% in winter to 50% or 60% in summer.


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## ehanes7612 (Sep 27, 2012)

in my experience they do best in humidity around 70%


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## The Orchid Boy (Sep 27, 2012)

What could I do to increase the humidity? I've found that trays of water with gravel doesn't do much. I could add a steam humidfier, I've tried that before but doesn't seem to work too well either. My paph. sanderinum should be here tomorrow. It won't die without high humidity will it? I'll ask Leo Schordje about this....


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## keithrs (Sep 27, 2012)

The Orchid Boy said:


> What could I do to increase the humidity? I've found that trays of water with gravel doesn't do much. I could add a steam humidfier, I've tried that before but doesn't seem to work too well either. My paph. sanderinum should be here tomorrow. It won't die without high humidity will it? I'll ask Leo Schordje about this....



No, It won't die. Ultrasonic humidifier works pretty good. Just remember when the humidity gos up, you have a higher chance mold will take hold. You can also mist the plant daily.. Maybe twice-a-day.

Humidity is not the end all....


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## The Orchid Boy (Sep 27, 2012)

That's a relief. I was just thinking that I have a Nepenthes sanguinea seedling and nepenthes usually like it very humid. It is doing well. It would probably grow faster and better if it was in higher humidity but it is managing.


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## keithrs (Sep 28, 2012)

Humidity does make a big difference.. Especially thin leaf plants or plants with roots exposed. I sure there other situations that humidity is a key factor.


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## ehanes7612 (Sep 28, 2012)

you can use the ultrasonic humidifier bu they crap out real easy...i find the warm humidifier , the ones with the heating element work best...they will add a little to your electric bill (300 and 500 watt settings)and require cleaning every now and then but they are more reliable than the ultra sonics...but with humiidty you need an enclosed space...and you do have to be careful with mold


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## Cheyenne (Sep 28, 2012)

The best advice I can give you regarding paph sanderianum is to keep it as simple as possible. Some of the first paphs I started to grow were sanderianums. I searched through all the habitat data and all the recommendations from other people because I wanted to give them the best possible conditions to thrive. Since they grow on limestone with moss on it I tried rock in the mix with sphagnum on top, I tried sphagnum in the mix, shallow pots, baskets for more air. All to try to mimic their environment. After all that I came to the conclusion that they grow better in a simple paph mix of bark, charcoal and perlite. I would put them in clear pots so you can see the moisture in the mix. Don't let them dry out completely but water as it approaches dryness. I did figure out they don't like repotting as much as other paphs so whatever you decide to do leave them alone and let them settle in. The fertilizer you have will work fine but try to keep it to 1/4tsp per gallon every two weeks. Use good quality water. Try not to overwater because if you loose the roots they take years to recover. Keep them warm till they are big then give them a dip in temp in fall to set buds. Try not to over think it, it is easy to do when you read all the recommendations and information out there.


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## Rick (Sep 28, 2012)

The Orchid Boy said:


> I wondering how much and how often to fertilize. I have a 30-10-10 and a 6-30-30 fertilizer.
> 
> 
> Thanks.



I'd pitch the 6/30/30. It's only good for corn or anything you only want to grow for a single season.

Stick with the 30/10/10 and as Cheyenne says use at 1/4 strength.

I would use your well water to get lots of calcium into the system. Better yet dilute your well water with rain or RO water till the conductivity is down around 100useimens/cm. If you use straight RO or rain water (with no well water) then definitely add some oyster shell or crushed limestone to your potting mix.

Potting mix is no big issue. But I like lots of rock so there is less bark/moss/CHC to accumulate salts.

Most growers think the high humidity is a big deal for long term health of sanderianum (not just a blooming quirk). So I'd figure out ways to get a good 70%.


This is good for just about any paph not just sanderianum


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## The Orchid Boy (Sep 29, 2012)

I could put it outside for part of the year where it is usually so humid it feels like you are drowning in the air. In winter my humdity is around 40% or 50%. In summer inside it is around 60%. Summer outside the humidity is always above 75% usually above 80%, this year wasn't as humid though. What could I do for more humidity inside? I grow my plants in my bedroom and I shut all the vents and keep my door closed. I have a fish tank with a partially open top and some carnivorous plants that are always sitting in water. I also mist the plants once in a while. Maybe I should make or get some humidity trays...


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## Cheyenne (Sep 29, 2012)

Your sanderianum will grow fine without high humidity. But it will grow better with it. One of the main concerns is sometimes with low humidity the bark will dry out fast and it is harder to grow real good roots. I have grown them fairly well for years with humidity around 50 percent. I dont know what kind of room you have but you coulduse a old fish tank or make an enclosure out of plexiglass from the hardware store. I do this for my plants that like high humidity.


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## cnycharles (Oct 2, 2012)

it's easy to make enclosures out of small pvc plumbing fixtures and wrap it with plastic sheeting (or any other built enclosure, wrapped with plastic)


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## Justin (Oct 2, 2012)

Cheyenne said:


> The best advice I can give you regarding paph sanderianum is to keep it as simple as possible. Some of the first paphs I started to grow were sanderianums. I searched through all the habitat data and all the recommendations from other people because I wanted to give them the best possible conditions to thrive. Since they grow on limestone with moss on it I tried rock in the mix with sphagnum on top, I tried sphagnum in the mix, shallow pots, baskets for more air. All to try to mimic their environment. After all that I came to the conclusion that they grow better in a simple paph mix of bark, charcoal and perlite. I would put them in clear pots so you can see the moisture in the mix. Don't let them dry out completely but water as it approaches dryness. I did figure out they don't like repotting as much as other paphs so whatever you decide to do leave them alone and let them settle in. The fertilizer you have will work fine but try to keep it to 1/4tsp per gallon every two weeks. Use good quality water. Try not to overwater because if you loose the roots they take years to recover. Keep them warm till they are big then give them a dip in temp in fall to set buds. Try not to over think it, it is easy to do when you read all the recommendations and information out there.



great advice. do this and you will be fine.


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## The Orchid Boy (Oct 16, 2012)

I've been able to keep my humidity at around 50%. I repotted into a clear/opaque pot to moniter root growth and moisture levels. It had lots of healthy roots! It was a little hard to get it out of the old pot. I potted it into a mixture of medium bark, charcoal, perlite, and the tiniest bit of sphagnum moss. I also added a tiny bit of crushed oyster shell to the top of the mix.


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## Cheyenne (Oct 16, 2012)

Sounds like your right on track. Keep an eye on the moisture and water as it is almost dry but not totally. You just don't want to keep it to wet for too long.


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## chrismende (Oct 17, 2012)

Orchid Boy, when I was growing a couple of multis in my livingroom I put their pots over a ceramic saucer that was always filled with water. The whole thing was up on a plant stand. The pots were just over the water, up on something like large stones to keep them from sitting in the water. They did very well for a couple years before I got my greenhouse. Beautiful, shiny long leaves and good blooms.


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## The Orchid Boy (Nov 5, 2012)

For the past week or so my sanderianum has been taking quite a bit more water. Why? Is it going to grow a new leaf or something?


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## Leo Schordje (Nov 6, 2012)

water demand varies with temperature, humidity and light. If you water on a schedule, the plant suffers. Water them when they need it. Myself, I water every 3 to 7 days. Most often every 5 days. What does the variable mean? I stick my finger into a couple pots, down in to the first knuckle. If its moist, I don't water. If its dry, I water. Not on a schedule, but when the plant is approaching dry. At first knuckle depth, there is still moisture further down into the pot, so its not bone dry. 

I don't worry too much about humidity. During episodes of low humidity, the leaves will keep growing, its the roots that stall out. But during my humid summers, I get my root growth for the year and it carries me through the winter, low humidity season. 

Really, in all honesty, don't do anything wildly different than what you have done for your Paph Magical Venus. You rebloomed that. Give the sanderianum essentially the same treatment. They are not wildly different. Cheyenne's comments as well as everyone else have been dead on. Don't overthink it. 

The hard part is to just be consistent with what you are doing, and not try something new every other week. You can get this to bloom, just fall into essentially the same routine you had with the Paph you have already rebloomed.


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## polyantha (Nov 6, 2012)

ehanes7612 said:


> i grow and bloom them pretty well, i have soft water looming around 6.5 pH, and they tend to like to be a little wetter than most multi's. i have found a variety of mixes work for them..i use a low K diet now although when i used a higher K diet they grew just fine..all in all they seem a lot more forgiving than a lot of paphs..actually, some of the hybrids can be less forgiving than the species....but they do prefer high humidity too



I agree. Little wetter. And they are much more forgiving.
You can add shells if you want to, but i would definitely avoid oyster shells. These kind of shell has layers and in between they hold salts that are not good for the plants. I had problems with them in the past


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## The Orchid Boy (Nov 6, 2012)

polyantha said:


> I agree. Little wetter. And they are much more forgiving.
> You can add shells if you want to, but i would definitely avoid oyster shells. These kind of shell has layers and in between they hold salts that are not good for the plants. I had problems with them in the past



I added a little crushed oyster shells but only less than 1/4 a teaspoon and it was very fine and powdery.


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## keithrs (Nov 6, 2012)

Probably has more to do with your micro climate.


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## Leo Schordje (Nov 6, 2012)

polyantha said:


> I agree. Little wetter. And they are much more forgiving.
> You can add shells if you want to, but i would definitely avoid oyster shells. These kind of shell has layers and in between they hold salts that are not good for the plants. I had problems with them in the past



The source makes a difference. The crushed oyster shell I get has definitely been washed. No easily soluble salts. relatively little dust. Also what I get is not flat plates of shell but nice 3 mm to 5 mm square pieces. Nicely chopped or crushed. No flat plates. In the US what is approved for poultry use is a fairly good for orchid purposes product. 

This problem applies to all growing media. When one person talks about a product for a potting mix, their source may be quite different in quality than your own local source.


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## Rick (Nov 6, 2012)

Leo Schordje said:


> This problem applies to all growing media. When one person talks about a product for a potting mix, their source may be quite different in quality than your own local source.



If you go K-lite you can skip adding calcareous material to your potting mixes. This would also tend to reduce pot alkalinity and make low/no ammonia fertilizers (like straight calcium nitrate) more useful to the plants.

The amount of Ca and bicarb from your irrigation water and the amount already increased in the K-lite formula would supply more than sufficient Ca and buffering capacity to the system.

Presently if you use a high K fert in conjunction to a hard/alkaline water with calcareous potting ammendments, it's kind of analagous to driving your car with the foot on the brake and the gas at the same time.


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## Leo Schordje (Nov 6, 2012)

That light is dawning. I will be adjusting what I do. There is a 25 pound bag of K-Lite en route to my location. Haven't started it yet. I still have some 5 or so pounds of the original high K MSU left to use up.


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## The Orchid Boy (Nov 6, 2012)

So the "K-lite" is low in iron? I'm not sure I completely understand "K-lite". Could someone please explain? Thanks so much.


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## naoki (Nov 7, 2012)

Rick said:


> If you go K-lite you can skip adding calcareous material to your potting mixes. This would also tend to reduce pot alkalinity and make low/no ammonia fertilizers (like straight calcium nitrate) more useful to the plants.



Rick (or someone), could you explain the theory behind this? How does the effectiveness of NO3 fertilizer increase with lower alkalinity? I went through the long K-lite thread at one point, but I don't remember this part. It's probably related to anion vs cation, but I can't figure it out.


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## Leo Schordje (Nov 7, 2012)

Rick is the best one to explain this, K-lite refers to Low Potassium (the symbol for potassium is K). Potassium salts are usually the salt of choice to make inorganic fertilizers because they are extremely soluble in water. Potassium is a necessary nutrient, and while plants don't need a lot, it was always assumed that because potassium is so soluble in water, any excess would flush out without being harmful. 

It turns out, that in the unique conditions set up by orchid growers, potassium does accumulate to the point where it does interfere with the uptake of other nutrients, like Calcium & Magnesium. Especially when we orchid growers try to push our plants for more rapid growth. 

The K-lite formulations are designed with a lower amount of potassium, about 2 parts to the 13 parts nitrogen. In the traditional older style MSU fertilizer the potassium was almost equal in concentration to the nitrogen. 

So that is what is different about K-Lite. Have I got the basics right Rick?


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## Rick (Nov 7, 2012)

You are correct Leo, and here's some more explanation.

When we designed K lite, we worked around the original MSU Rain or Pure water versions, rather than the well water version.

The pure water version actually has 2 differences from the well water version.

The pure water version has higher levels of Ca and Mg, AND a low percentage of ammonia (compared to nitrate). Bill Argo did some pretty nice work to demonstrate that plants in low alkalinity systems favor nitrate over ammonia for their choice of N.

The well water version has lower Ca and Mg AND a higher percentage of ammonia, since well and other surface waters typically have higher alkalinity values (along with the hardness caused by Ca and Mg).

Alkalinity is the measure of buffering capacity, and at the pH we typically opperate at is caused mostly by bicarbonate ion. pH alone will NOT tell you how much alkalinity is in your system. To test for alkalinity you titrate to figure out the "acid demand" of the system required to use up all the bicarbonate ion. (this is actually a simplified discusion on this).

Anyway when we designed K lite, we opted to stick with the low alkalinity system of the pure water users (primarily since us RO water users were having the biggest issues). So K lite is 98% or so nitrate based N with only 1-2% ammonia. 

So if you want to run water and potting mix alkalinity levels at higher concentrations (>50ppm alkalinity) then you may see some nitrogen starvation due to the low ammonia availability.


BTW the iron (and all the other trace goodies) in K lite are the same as regular MSU mixes. All we did is reduce K and P, and increased Ca and Mg.


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## naoki (Nov 7, 2012)

Thank you very much for a detailed info, Rick. I'll try to look into his work when I get some time. It's interesting because I thought plants do convert nitrates to ammonium before they incorporate N into protein. But I guess they prefer to absorb nitrates in low alkalinity. I wonder why, and the plants are pretty complicated.


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## The Orchid Boy (Nov 7, 2012)

Thanks for the explanations everyone! 

How are chemical fetilizers and organic fetilizers different? How do the plants respond and get nutrients differently? I have some rainwater that leaves fell into and Ramona and rooting leaves turned the water dark before I could get them out. I was thinking about putting some manure in an old pillowcase and making some "fertilizer tea" because this worked well for a relative of mine with their houseplants and I started using organic fertilizers with my other plants with good results. I believe in organic methods of gardening and fertlizing myself and I was wondering if I could replace chemical fertilizers with organic ones, either homemade or store bought. Just want to get your guys' ideas...


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## Rick (Nov 7, 2012)

naoki said:


> Thank you very much for a detailed info, Rick. I'll try to look into his work when I get some time. It's interesting because I thought plants do convert nitrates to ammonium before they incorporate N into protein. But I guess they prefer to absorb nitrates in low alkalinity. I wonder why, and the plants are pretty complicated.



http://www.firstrays.com/PDF/Part 3 - Fertilizers.pdf

Try this.


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## keithrs (Nov 8, 2012)

The Orchid Boy said:


> Thanks for the explanations everyone!
> 
> How are chemical fetilizers and organic fetilizers different? How do the plants respond and get nutrients differently? I have some rainwater that leaves fell into and Ramona and rooting leaves turned the water dark before I could get them out. I was thinking about putting some manure in an old pillowcase and making some "fertilizer tea" because this worked well for a relative of mine with their houseplants and I started using organic fertilizers with my other plants with good results. I believe in organic methods of gardening and fertlizing myself and I was wondering if I could replace chemical fertilizers with organic ones, either homemade or store bought. Just want to get your guys' ideas...



I'm a huge organic fan. I made my own ver. of k-lite from earth juice micros, mexi bat guano, kelp, and worm castings. I didn't get a chances to use it long enough(once).... Life happened... I do top dress my Cym.s and three paph I have with organic "vegetable" food. The cym. and one paph I have are in chc, sand, leca, and small bark. The others are in orchiata-leca mix. The plants in chc love the top dressing. The others not so much. My guess is the microbes find it a lot easier to make a home in the chc....Stays more concestantly moist. I also add red wigglers to every pot... They love chc!


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## keithrs (Nov 8, 2012)

I would throw worm castings and molasses in that bucket of leave "tea" and aerate it for 24-36 hrs. I try and stay away from horse and cow dung.


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## The Orchid Boy (Nov 8, 2012)

I have horse, cow, goat, chicken, duck, and geese manure available.  So is most animal manure too strong for orchids?


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## cnycharles (Nov 8, 2012)

by itself manures are too strong for plants, but if you compost them, and then make teas by using a small amount 'brewed' in water, you can use the water on your plants. there was someone who was using composted cow or horse pies in pots, and planting their orchids directly on top of them  they reported very good results, but of course everyone's mileage may vary depending on just how they do things, and their growing environments


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## keithrs (Nov 8, 2012)

The Orchid Boy said:


> I have horse, cow, goat, chicken, duck, and geese manure available.  So is most animal manure too strong for orchids?



Out of those, I would use horse. But you must compost it to get the microbes to break it down into usable form of fertilizer. 

My recommendation would to use bat guano or fish emulsion.... You'll have better results.


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## Eric Muehlbauer (Nov 8, 2012)

I remember.... it was a guy named Nic in either Tasmania or New Zealand. Deceased, sad to say. But he continually posted on the old OLD (precursor to OGD) about his great success growing Cymbidiums in straight horse manure. I don't even think he composted it. As for worm castings...don't they raise the pH?


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## keithrs (Nov 9, 2012)

Eric Muehlbauer said:


> I remember.... it was a guy named Nic in either Tasmania or New Zealand. Deceased, sad to say. But he continually posted on the old OLD (precursor to OGD) about his great success growing Cymbidiums in straight horse manure. I don't even think he composted it. As for worm castings...don't they raise the pH?



When I brew worm castings in ro with kelp, I get a pH of 4.7-5.


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## keithrs (Nov 9, 2012)

The problem with teas is you may run into micro nutrient problems. You'll have to use Ca/Mg supplement. In soil environments, You can add lime or other sorts of Ca/Mg supplements that break down over time. Very hard to do with plants in very course mix or on mounts.


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