Ann: The reason it hasn't been done is that there are many variables and most fruits under most conditions don't require a lot of fertilizer. In fact, too much fertilizer can be just as bad or worse than not enough. Too much nitrogen can lower fruit eating quality and cause excessive vegetative growth. In general, if your trees are as big as you want, have good foliage, and reasonable growth each yr; then they don't need more fertilizer. A soil test is always a good place to start but if you can read what your trees are telling you, then you don't need that. Many people apply a good organic mulch and find they don't need much else. If you apply a chemical fertilizer then early spring and early fall are good times for application. The Fruitnut

Because almost the entire population of my greenhouse plants are actually planted into the ground, I use a double-pronged attack, LOL. I scatter Nutricote (which is slightly different from Osmocote) on the ground around the plant bases as a continuous slow release. I use it on the palms, but in addition I also scatter some regular palm fertilizer around them. I also use Nutricote in all my potted plants, like Hoyas and orchids that have actual media, and in addition, they also get some water soluble fertilizer every so often (I prefer Peter's Excel Cal/Mag 15-5-15) For mounted orchids, I use either 20-20-20 or Jerry's Grow Orchid fertilizer in a hose end sprayer. I kind of alternate these on no real set schedule, and the plants on the ground get a little extra somethin-somethin from the drips of this. And, additionally, I give the palms and other heavy feeders like heliconias and anthuriums a foliar spray 3-4 times a year of Chelated Palm Nurtitional, which has all the trace elements. You may say, "Gee, sounds like OVER fertilization to me!", but, the Florida soil I have to work with is basically just sand, and is very nutrient poor. It drains like a sieve, too.

I find that deciding how to fertilize is up to each grower's environment, water quality, and judgement. So it is not always a simple conversation. Everyone has a different opinion. However, most will tell you to ignore the label and fertilize more frequently at a weaker dosage than the labels imply. Here is what I do: I fertilize with every watering using .25-.5 teaspoons per gallon. I generally use the MSU formula fertilizer or Dyna-gro Gro or Bloom. I switch to the bloom late summer to late fall, but I have not noticed a difference. Once I use all of the Dyna-gro Bloom I will just go back to the MSU full time. I add CalMag and a mirco-nutrient pack once a month. I think I have a solid fertilization regime, but it is not stellar. Most importantly it works for me and 90% of my collection. And it has worked well for my Phals in the past. I like the way First Rays explains fertilizing: Explaining fertilizer dosage You may want to look at some of his other articles also.

With regards to fertilizing orchids, my impression is that success is measured more with what you don’t see, than what you do. So a picture that represents proper feeding of an orchid would be far less convincing and instructive than a picture of an orchid that has been over-fed. The variety of approaches that have been employed by various orchid-growers and touted by experts is mind-boggling. But the common thread among the cognoscenti seems to err towards “gently.” In the several decades that I’ve been growing orchids (much of which has been spent with no firm concept of what orchids actually need to support their growth) there seems to have been only one major “breakthrough” which has soared above most other approaches, and which has lasted in its renown to this day. That of course would be the MSU approach of utilizing relatively low phosphorus in its overall balance, together with employing mostly nitrate-sourced nitrogen and avoiding Urea nitrogen altogether. The other guiding concept in fertilizing would be summarized by the recommendation that a steady, consistent and relatively weak fertilizing regime is more supportive to orchids than strong periodic fertilizing. There are several approaches to this process, according to how scientifically-minded one happens to be. One would be to determine optimal PPM nitrogen over a prescribed period of time based on the type of water you happen to be using. The other, simpler approach (after ensuring that your water source is acceptably conducive to orchid-growing to begin with) is to feed weakly weekly at ¼ strength of the monthly recommendation, assuming a 20-20-20 or equivalent formula. Or using that same strength as a constant feed with periodic flushing, depending on genus and its tolerance to added “salts.” For example, I don’t hesitate to constant feed my cattleyas and phalaenopsis with a monthly flushing. But I wouldn’t feed my paphs with that strength more frequently than once a week, so at least one, of not two plain water applications fall between feeding. In addition, good general feeding practice frequently advises pre-watering before applying fertilizer to buffer sensitive roots. Given the application of a ¼ strength solution I feel this is less important for some genera that others. Finally, as some readily available fertilizers are balanced for acid-loving plants, it would be inadvisable to assume that any fertilizer that happens to be on hand would be helpful to orchids. The below link accesses an article on MSU fertilizing and a table that sets out two formulas. It is important to remember that orchids do most of what they do by virture of the light and supportive moisture that they receive. The picture below represents an overfertilized, and arguably over-lit paph from an overly-eager grower, i.e., me. MSU Fertilizer Formulas