Humic Acid?
 

Many moons ago, when I was experimenting with developing my own, better-but-much-cheaper SuperThrive (I did so, but the idea was abandoned, due to EPA regs), I began using humic acid as an additive to the formulation.

I am quite certain of its benefit in soils, as it helps release otherwise-sequestered nutrients, but I questioned its applicability to orchid-growing.

I know this is quite unscientific, but about 4 months ago - just before the time I had to start mostly "ignoring" my collection due to the various surgeries I endured - I added a liquid humic acid concentrate to my fertilizer feed tank, so have been feeding with it (it ends up being about a teaspoon per gallon), and it "looks" like it may be a "plus" after all, as I am seeing more growth and blooms than I had been (again I'll state - it's quite an unscientific assessment).

Anyone else have any thoughts or experience?

I use humus as a main component to my entire Paph. collection, and it is VERY beneficial. Humic acid is in humus, so I can add to what you said. Quicker growing, healthier plants is all that have come out of switching to that organic substrate...

-PM

:hmm Interesting. Where does one obtain humus and/or humic acid? Any old garden store? Id be curious to try it out on some my guys.

As is usually the case when I try stuff, I buy large volumes at wholesale and sell off the excess, but most hydroponic stores will carry it in a soil-additive granular form, and as I use, in a liquid extract.

Ray, what acid do you use now if you want to lower the pH of your s/h media? I just purchased from a local hydorponic store a pH lowering concentrate of nitric, sulfuric and phosphoric acids.

I don't use anything - but the stuff you purchased is fine for lowering the fertilizer solution pH, which is what you're doing, right? Nothing you do will have that great an affect on the medium itself.

Humic acid is a weak acid, so will have very little impact on fertilizer solution pH.