Organic Fertilizers on Mounted/Bare-Root Orchids

[galguibra]

I've been seeing some suspicious (?) advice/claims from quite a few video guides and articles recently, and I was hoping to get some more experienced growers' opinions on it: can mounted/bare-root orchids use organic fertilizer?


For some reason, I've seen several people saying it won't work at all or would be wildly inefficient, but it strikes me as odd since in the wild all any orchid would be getting is rainfall runoff of decaying organic matter. I understand there are certain symbiotic fungi/bacteria that aren't usually present when growing at home, but surely there's something more to this, right?



I definitely get why inorganic would be efficient, since everything is readily available in ionic form (ignoring the increased risk of root burn, which is neither here nor there for the purposes of this question), but I would think that especially with an organic mount like cork bark, wood, etc, that there shouldn't be any issue with organic nutrients. I guess I can see why totally bare-root orchids with an inert support like, say, Vandas grown hanging in a plastic basket might benefit less, but even then I'd still expect to see some benefits spraying organics on the roots and leaves.



I specifically grow indoors on a cork mount I boiled, soaked, and baked to sanitize before using it, but I do include beneficial bacteria/mycorrhizae in my nutrient solution, so I can only hope that makes a difference. I'd also be especially interested to hear if anyone has experience with the more "artificial" organics like minerals chelated with organic acids, but the conventional stuff like fish emulsion, bone meal, etc, is definitely fair game too!

[Roberta]

I think the biggest issue with the various "fertilizer soups" is that the compositon of the actual nutrients (and availability) is largely unknown. Since the most important fertilizer nutrient is nitrogen, do you know what the plant is actually getting? Particularly with mounted plants, the contact time is pretty short so that would tend to reduce what they're actually getting even more, most just washes off. Fortunately, orchids don't need much of anything, so if they get less than what you think you're giving them you probably can get away with it. Remember, fertilizer is the least important of all the cultural factors... get everything else right, and as long as they are getting some, the details are probably not critical.

[Ray]

Whether originating from organic or inorganic sources, the ions taken up by plants are identical.

[galguibra]

Originally Posted by Roberta

I think the biggest issue with the various "fertilizer soups" is that the compositon of the actual nutrients (and availability) is largely unknown. Since the most important fertilizer nutrient is nitrogen, do you know what the plant is actually getting? Particularly with mounted plants, the contact time is pretty short so that would tend to reduce what they're actually getting even more, most just washes off. Fortunately, orchids don't need much of anything, so if they get less than what you think you're giving them you probably can get away with it. Remember, fertilizer is the least important of all the cultural factors... get everything else right, and as long as they are getting some, the details are probably not critical.

That makes sense, yeah! The stuff I have at home all comes with guaranteed third-party lab analyses and a breakdown of everything inside, so I'm at least confident about what's going into the spray bottle and at what concentrations.


I do my best to thoroughly soak the mount too when I spray, especially since I just have the one orchid for now and making any less than ~100mL of solution would mean dosing out even less of some nutrients than the 0.05mL I'm already doing, so the rest of the liquid might as well go somewhere. Do you think that actually provides long-term accessible nutrients though? My logic was that the beneficial microbes would continue breaking down the excess nutrients on/in the mount, which I'm hoping will encourage the roots to explore and attach to it more readily.



I'd also thought about doing monthly or semimonthly soaks/flushes of the entire mount, just to keep things nice and balanced, but I already water with distilled water as it is, so I'm not sure if there's much point. Would be interested to hear your thoughts though!

---------- Post added at 11:06 AM ---------- Previous post was at 11:03 AM ----------

Originally Posted by Ray

Whether originating from organic or inorganic sources, the ions taken up by plants are identical.

That's pretty much what I figured too, since there's usually only one form that's ultimately bioavailable, so at most the organic stuff would have some lagtime while it gets processed and broken down. To me that's probably for the best anyway, since it makes the process more gentle and consistent

[Roberta]

Hard to say what the long term benefits are... mine get a low (half teaspoon/gal of MSU) spritzing about every 2 weeks, a shot of Kelpak once a month or 6 weeks. So basically hardly anything. And they do just fine. People tend to focus on fertilizer because that's easy to control and measure. The rest of the environment is tougher, but far more important.