s/h: which fertilizer

[sept2256]

Well, I decided to go in deep in all the threads before ask something, …but the temptation to know is so strong…that I am already here.
First of all, sorry for my bad English, you know, for a lot of Italian people this is really a hurdle.
I’ve always had problems with orchids roots, probably due to the indoor environment, and the only orchids that give me a lot of satisfactions are phals. One year ago I tried S/H colture starting from a lttle and poorly pseudobulbe of cambria. It produced a lot of new roots and now there is a new pseudo bulbe that seems near to give flowers. So, before try again with other orchids, I would like to have some information on this (for me) new technique. The Ray website contains a lot of good indications, but here in Italy it is difficult to find the right materials. Therefore, for example, PrimeAgra probably is the best, but we don’t have it, and following Ray’s test explanations I tried some LECA and other materials, and at the end I realised that the better substrate I can use, is volcanic rock (granules of about 10 mm). The capillarity of this material permits to have at least 13 wet cm over the water line.
But now comes my questions about fertilizer.
1) With bark I generally use 20-20-20 and in this period 30-10-10. I never asked my self the right formula of these fertilizers, but I think that before to use them for s/h, I have to know if with S/H technique NO3 is better than NO2 or ammonia… or viceversa! How can I choose the right formula?
2) Which concentration (g/L) I have to use?
3) And what about micro-elements?
…is it too much?
Thank you,
Pierangelo

[sept2256]

Hello!
Nobody can help me?
Probably they are silly questions, but please, at least tell me that they are! This is the first time I've joined this forum....have I escaped some rules?
ciao,
Pierangelo

[Learner]

Pierangelo:

I am not qualified to answer your questions, but give it a little time and I'm sure some of the more experienced members of the Forum will get back to you with all the answers to your questions. This is a good group for giving help.
Jim

[irrka]

Ray's site has a calculator on it, where you plug in the number from the fertilizer you have and it gives you how much you need for whatever ppm of N. Most people go for around 125. Otherwise i think you just go with a balanced fertilizer. I'm sure Ray's going to give a much better explanation though!

[Ray]

Better? Doubtful. More extensive? Of course!

Fertilizers are not as precisely critical as some think.

My experience tells me that for a varied collection in less-than-ideal conditions, 125 ppm N is a good compromise on the concentration. I cannot speak to the valence of the nitrogen, but in most fertilizers, isn't it going to be mostly NO3 anyway?

I recommend against using the 30-10-10, as all that nitrogen is unnecessary and can lead to weak plants. I find it is better to use a more-or-less "balanced" fertilizer at all times. Don't forget that in the S/H environment, the nutrients are always available, so it is not necessary to boost the nitrogen during peak growth periods (which can vary from plant to plant anyway).

Unless your fertilizer has the minor elements in it, you should supplement it. In reality, orchids get little-to-no nutrition from their medium, so that guidance is universal, and not limited to S/H culture.

In the last 35+ years of orchid growing, I have used a 15-30-15, 7-9-6, and for the last 5 or 6 years, a 13-3-15 (all with a complete array of minor ingredients), and was happy with all of them.

[sept2256]

Thank you all.
So, in fiew words, it seems the important is that all elements are available and, in non optimal growing conditions (unfortunately this is my case), N concentration should be lower, at about 125 ppm.
Just another question. I have a fertilizer of Bayer containing 8-4-6 and micro-elements (with EDTA) stable at pH 5-7. General speaking, is pH an important parameter that have to be controlled?
Thank you again,
Pierangelo

[Ray]

Yes, pH is important.

Most orchids prefer the high-5's to low 6's, and can tolerate it to a bit above 7. Some slippers prefer it on the alkaline side, in the upper 7's.

My fertilizer solution is about 5.8, and I have had no issues with anything, including some paphs and phrags.

[sept2256]

Thank you Ray!!

[Keith Sheridan]

What is 'S/H' environment?

[Ray]

All about Semi-Hydroponics