Clay,
If you will reread my post, I stated that I HAVE used similar concoctions, but as others pointed out, I wouldn't recommend it for non-terrestrials.
The point is that plants need a far wider range of nutrient minerals than is provided by beer, Epsom Salts and ammonia. Terrestrial plants can get most of them from the soil, and your concoction is a good general "booster tonic". However, continuous feeding of that with no supplementation of those minerals will lead to rapid decline, and in the case of epiphytes that use the growing medium only as mechanical support, the nutrient solution is the only source of them.
Some of the essential minor- and trace minerals are mobile within the plant, so as the plant grows is can spread them around for quite a while, but others are fixed in the plant tissues as they grow, so a failure to provide them on a routine basis will lead to deficiencies and overall plant decline, opening them up to easy attack by fungi, bacteria and viruses.
Try this experiment: buy some magnesium nitrate Mg(NO3)2.6H2O and feed your plants at a rate of 1/2 teaspoon per gallon. They will grow and bloom like wildfire - probably better than you're seeing now. Unfortunately, only feeding them nitrogen and magnesium is like feeding a kid candy as a regular diet: they will be active and happy and eventually crash.
A philosophical point: We participate in these online forums as a way to share what we know in order to better our cultural techniques and methodologies. I am an engineer and have been constantly experimenting over the 35+ years I have been growing orchids. The engineering background also makes me want to know more about the science behind the things we observe, and I have "taken up the flag" of the crusade begun by the late Bert Pressman to replace "old wive's tales" with solid scientific explanations (most of them are based upon fact...at least somewhere in the past).
My quick treading on your post was nothing more than an effort to correct the dissemination of incomplete information, as it was not, by itself, incorrect. It was not meant as a personal attack, and I'm sorry if you took it that way.
Once you have participated here more and understand the overall dynamics, I hope you'll learn to appreciate the basis and goals of my comments better.
|