Grow More Orchid Foods

[Ray]

OW - I mean this entirely good-naturedly, but I think you and I are going to debate this until one of us dies!

Yes, urea can be used directly by orchids, and I agree with the statement that "Urea-free, or even low urea formulations, are completely unnecessary", "but urea being used "as efficiently" is 1) incorrect, 2) not proven by the single study you love to cite, and 3) varies with the type, maturity, and condition of the plants.

Due to physics and chemistry, roots are better at absorbing nitrate-, and ammonium sources of nitrogen, while leaves are better at absorbing urea. Both can absorb all three, but it's a matter of degree, not all-or-nothing.

To me, that - all by itself - favors nitrates and ammoniums, as we try to avoid watering the leaves of the plant, to prevent stuff like crown rot, and so they don't get marred by residues. (As an analogy, we can absorb water through our skin, but if I'm thirsty, taking a drink seems more effective.)

Then we have to take the type-, and condition of the plants into account. Orchids can develop waxy cuticle layers on their leaves as part of their water-retention strategy. Some orchids develop heavy layers, others don't. The age, health and condition of the plant, and how it is being grown can also effect the thickness of those layers. If they are thick, they make the leaves more waterproof, limiting the likelihood of foliar uptake.

I have a friend who is a spectacular grower of paphiopedilum species, and he swears that adding a pinch of urea to his K-Lite regimen has been an improvement.

In my own case, trying to simulate what plants see in nature, I feed frequently, and at very low fertilizer concentrations. It therefore makes sense to me that the preferred chemical species are those that are quickly and efficiently taken up. On the "simulate nature" aspect, I suspect that there is a lot more plant-exuded nitrate and ammonium ions coming down on the epiphytes than there is urea from bird poop.

Mass-marketed fertilizers utilize urea simply because it is the overall cheapest from of nitrogen. For terrestrial plants, it is a very effective and efficient source of nitrogen. For epiphytes, it simply isn't that straightforward, but those manufacturers don't care about that, or expect that their customers understand it.

[NYCorchidman]

I will echo what others have said.
Any balanced fertilizer with trace elements added to it will work fine.

There are just so much hype about fertilizers and they are mostly useless. lol

I have used a few different products and have not seen any difference in plant performance.

Plus, I think most people care too much about fertilizing and actually go overboard. A lot of it comes from the delusion that "feeding" ( fertilizer is not food!!! plants make food themselves) will bring miracles. Simply not true.

Nothing beats overall healthy growing conditions. Good light (or should I say proper light), good watering, and correct temperature are the most important. and a bit of fertilizing here and there will help.
I have grown orchids (mainly phals, oncidiums, paphs) with NO fertilizing for about one year in the past and still saw no difference.

Certain orchids will need more than others because of fast growing rate during short period of time like large cymbidiums and certain dendrobiums, which will benefit greatly from fertilizing at the onset of new growth and again during the growing season. Then no more fertilizing is needed.