For the scientists, theorists, and observers...

[Ray]

Some of us here have begun to adhere to the frequent, but very dilute feeding regimen, and I have heard a lot of "experts" proclaim the benefits of using pure water. I have also heard it stated that the high-altitude species are particularly sensitive to water purity and require super-low TDS.

What is unique about their environment that would lead to that evolutionary development?

One thing I considered - based primarily upon in-situ photos I've seen - is that many of those species are bathed fairly steadily in a dense fog, rather than being exposed to daily intermittent rains as many of the lower-elevation species are. It seems to me that the more-or-less constant condensation of water on the forest canopy and subsequent dripping, would not allow the accumulation of leachates and exudates that could be channeled to the epiphytes below, leading to even lower nutrient concentrations than the lower-altitude plants might see.

Anyone else care to proffer a theory or two to support, deny, or offer an alternate interpretation of the cultural circumstances I'm not aware of?

 

[mormodes]

I'm glad you now grok water, no pun intended.

 

[limuhead]

I have seen a few orchids in the Monte Verde(? not sure if I spelled it right, been a while since I've been there) Cloud Forest in Costa Rica and some other high elevation areas the orchids were actually above the rain clouds. Even when it was clear there was still plenty of moisture in the air. I want to say humidity, but it was still really chilly, so it didn't feel humid so to speak. Most of what I saw were Plureothalids, Oncidinae, Twig Epiphytes and stuff. I can recall being in the mist, almost soaked because of it. I am pretty sure it was as pure of a source of H2O as you could find. In some areas I saw orchids covering branches, nothing above them so the runoff or whatever nutrients they were receiving were strictly? coming from the mosses and lichens growing with them. I have also seen Brassavola nodosa growing on low branches by the shore where they were being splashed by crashing waves and exposed to sea spray. They were some of the healthiest orchids I have ever seen. Personally I think that different plants, not necessarily orchids have adapted by necessity. Is it possible that the opposite could be true over time? That orchids grown in controlled conditions could adapt to more fertilizers? I have seen some Phal hybrids pushed to grow incredibly fast and produce massive amounts of flowers in a very short period of time...

 

[gonewild]

There is no canopy above high elevation orchids. Well, I guess that depends on what you call high elevation? There is nothing or very little to leach down to them. Even though the soil may be mineral rich the orchid toots generally don't grow into the soil but rather are suspended in thick moss layers.

 

[maitaman]

I spend quite a lot of time in La Fortuna. Those high cloud forests seem to me to produce a lot of things not found lower.
The orchid seeds germinate rapidly in the moss base. I haven't made any tests, but believe the moss produces sugars. Lower, the ditch mosses will aid germination where there are none of the agents (symbiotic fungi, etc.) that produce the sugars necessary for orchid germination. This is demonstrated where phrags, Onc, Oer, etc grow in very shallow moss on the asphalt of the road's edge.
The only minerals or fertilizers available are, basically, nitrates in the moisture produced by lightning and those sugars. The mosses decomposition release other minerals taken from the decomposition of the base (tree, rock - there are a hecjk of a lot of lithophytes up there). Those compost fertilizers and minimal, never being more than 1-1-1 with extremely small traces of others.
I have found that MgSO4 added to fertilizers is a great aid to culture. They don't want much other minors.

 

[orcoholic]

If the high altitude orchids respond better to purer water, my guess would be it's because the condensation and/or the clouds are made up of pure water and the orchids have evolved to not need any more than what's provided where they grow.

I don't think that a low, minimal TDS program makes any sense, however.

I've never dealt with any flowering or fruiting plant that does better with only rainwater as opposed to water with fertilizer (up to a point). Why would orchids be any different? My tomatoes and pansies and petunias grow better with fertilizers. Farmers know this. Potting mix companies also know it and even add fertilizer to their mixes.

From looking at the in-situ pictures posted here and elsewhere, I've never seen an in-situ orchid that comes even close to being as large, or as healthy looking, as the orchids that get CCE's. I'm pretty sure they've all been fertilized and a lot of them have had pesticides and fungicides used on them too. Certainly this does nothing to recreate what happens in their natural environment. To measure the amount of TDS running down a tree an orchid is growing on and using that as a bellweather for growing orchids is nonsensical. Maybe that is the minimum amount an orchid needs, but I don't see any reason to think that's the best amount.

The reason (IMO) "experts" say using RO water is better is because you can add MORE fertilizer without getting to the level that will damage plants.

It seems to me that we should be looking for the MAXIMUM amount of fertilizer we can add without damaging the orchid. If we wanted to recreate the water the orchid got in its native habitat, just collect rainwater.

 

[Rick]

I've never dealt with any flowering or fruiting plant that does better with only rainwater as opposed to water with fertilizer (up to a point). Why would orchids be any different? My tomatoes and pansies and petunias grow better with fertilizers. Farmers know this. Potting mix companies also know it and even add fertilizer to their mixes.

Cultivated/selected fruiting anuals are way different than orchids. But even the county agri extension service will differ with your opinion dramatically when it comes to feeding tomatoes versus nut or fruit trees (which are generally not given anything).

Orchids are adapted to living in nutrient poor conditions (year after year) and hence came up with adaptations like producing seed that do not have any food for the embryo. Or producing mimic flowers that offer no nectar reward for pollinators.

Orchids are among the lowest energy plants out there. Also at altitude everything is colder and as mentioned above, the "drip down from the canopy effect" is also reduced (hence even less material and energetic needs).

The typical "weakly weekly" feed rate of 100ppm is orders of magnitude more than orchids see in the wild. You can try piling on if you like but most of us are getting better results with much lower concentrations.

 

[orcoholic]

Orchids are adapted to living in nutrient poor conditions (year after year) and hence came up with adaptations like producing seed that do not have any food for the embryo. Or producing mimic flowers that offer no nectar reward for pollinators.

Orchids are among the lowest energy plants out there. Also at altitude everything is colder and as mentioned above, the "drip down from the canopy effect" is also reduced (hence even less material and energetic needs).

The typical "weakly weekly" feed rate of 100ppm is orders of magnitude more than orchids see in the wild. You can try piling on if you like but most of us are getting better results with much lower concentrations.

This still says nothing about whether orchids will do better with more fertilizer (than they get in nature).

1. Of course orchids have adapted. Every other plant has also adapted to its natural habitat. This still doesn't mean that they wouldn't do better with more nutrition. There is a much larger germination rate when seeds are placed on agar with added nutrition than in nature. Why the seeds have no food - noone knows that. There is only speculation.

2. We don't know whether or not high altitude orchids will grow better in-situ if they get more fertilizer. Maybe someone that visits the cloud forests, or other orchids in-situ, could fertilize a couple and not fertilize a couple others. I think the fertilized ones will do better - a lot better.

3. Just because 100ppm is orders of magnitude more that what orchids get in nature, doesn't mean it's not the best (or a better) rate to give orchids.

I'm not saying orchids won't survive at the minimal levels they get in nature - and I think 10N is real minimal - , I just think that they do better at higher rates and the growers that are growing using minimal fertilizer levels aren't growing their orchids at anywhere near their maximum potential.

 

[gonewild]

Those compost fertilizers and minimal, never being more than 1-1-1 with extremely small traces of others.

Are you basing 1-1-1 on some analysis report or only basing it on your educated guess?

 

[Rick]

This still says nothing about whether orchids will do better with more fertilizer (than they get in nature).

There have been a handful of actual trials trying to "optimize" fert inputs to orchids.

None of them done on species (all mass prop hybrids).

None of them include environmentally relevant levels of fert in the regime for comparison.

In the case of Cattleyas in the 197~ Cornell U study, the lowest levels of nutrients did the best. I can't recall if anything significant was noted for the hybrid Phalaenopsis or Cymbidium.

Also most trials are only for one growing season.

So unless you want to start your own trials with something like D cuthbersonii then you'll be stuck with a lot of anecdotal information of folks killing sensitive orchids and blaming it on everything but fertilizer regime.

 

[Rick]

, I just think that they do better at higher rates and the growers that are growing using minimal fertilizer levels aren't growing their orchids at anywhere near their maximum potential.

After years of growing at higher rates I, for one, am getting much better results at rates at or just above environmentally relevant.

And I don't think I'm all by myself on this either.

 

[Rick]

I have also heard it stated that the high-altitude species are particularly sensitive to water purity and require super-low TDS.

Can you give us some examples?

 

[Rick]

Looking at other correlations:

Dwarfing seems to be a common phenomenon at elevation.

And it seems to be genetic so simply moving things down the hill doesn't turn them into giants.

But if you recall the article Stone posted about small plants having disproportionately reduced metabolisms relative to large plants, then that would also predict that general nutrient uptake (including inorganic nutrients) would be reduced for small high elevation species.

 

[orcoholic]

After years of growing at higher rates I, for one, am getting much better results at rates at or just above environmentally relevant.

And I don't think I'm all by myself on this either.

I don't think you are either, just in a very, very small minority.

FYI, I have been using your low K idea (mixing my own) for about a year now - maybe a little less. My orchids have never looked better. I am watering at Ms of 1 (400 - 450 TDS) and Ph 6-6.5 (as I have for years now).

I went into my greenhouse today and took some pics of the orchids that are blooming now - plant and flowers - but don't know how to post them. Every file is too large - even after reducing to 72 pixels and 6x4.

Would like to see what you think. Can anyone tell me how to get the files to the correct size?

 

[Rick]

Can you give us some examples?

Can you think of any examples of high elevation fauna/flora that once brought to lower elevations/other countries became invasive species?

Invasive species as a rule are often physiologically very adaptable but generally limited indirectly by behavoiral associations like predatation/parisitism.

Given that folks have been moving orchids around the planet for hundreds of years, if they were that adaptable they should have taken over the world by now.

This would seem to contradict my "plants are plants" attitude when it comes to plant physiology, but since the advent of chemical/inorganic ferts we haven't been testing wild orchids at normal chemical levels.

I know of at least one species of African orchid that has gone invasive in Florida, but it is not a high elevation species.

 

[Rick]

I went into my greenhouse today and took some pics of the orchids that are blooming now - plant and flowers - but don't know how to post them. Every file is too large - even after reducing to 72 pixels and 6x4.

Would like to see what you think. Can anyone tell me how to get the files to the correct size?

Need to use something like Photobucket or Imageshack. The direct upload function from ST only does tiny files.

So reduce your photos to about ~500 X~500 and post them to Photobucket (or other internet photo sharing site) and then post them to ST by copy/pasting links from the sharing site.

 

[Rick]

2. Maybe someone that visits the cloud forests, or other orchids in-situ, could fertilize a couple and not fertilize a couple others. I think the fertilized ones will do better - a lot better.

Actually this one has been done in lowland areas a lot, though not generally targeting orchids as a species of interest. But nutrient enrichment generally reduces local diversity of indigenous species and increases prevalance of a few highly adaptive "weedy" often invasive species. (Think of algae blooms off the coast of Florida killing the coral reefs).

It is frequently argued, though rarely proved, that the reduction in diversity is due to "toxicity effects" of the chemical imput versus competition effects of the "weedy" species.

For instance I see lots of data of invertebrate species in West Virginia getting exposed to high TDS from mining. There are a handful of very rare mayfly species found in extremely low TDS waters that once the TDS is increased they disapear (exterpated). Howerver common species of crayfish from waters of higher TDS become very abundant.

In the lab, those Mayflies may not be as intolerant to higher TDS than suggested by finding them in only low TDS waters. But they may just be finding a haven from big successful crayfish in those impoverished waters that have no tolerance of low TDS.????

 

[orcoholic]

Let's see if this works. Hopefully they'll be large enough. The site looked like it was only going to post thumbnails.

http://imageshack.us/g/1/10378253/

 

[Rick]

I can click on photos and get them up to post card size.

Can you load them to the site bigger than that?

 

[Rick]

I have also heard it stated that the high-altitude species are particularly sensitive to water purity and require super-low TDS.

What is unique about their environment that would lead to that evolutionary development?

Maybe we could consider the culture success of different closely related upland and lowland species pairs. ??

Paph praestens vs Paph wilhelminae
Paph esquirolei vs Paph chiwanum
Phal fuscata vs Phal kuntsleri
Phrag caudatum vs Phrag exstaminodium

I'm sure there is a zillion other pairs. Probably lots of Dendrobium and Pleurothalid pairs to compare.