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[Roberta]

I don't think that the "bloom" vs "grow" fertilizers do anything useful. The so-called "bloom" formula is low in nitrogen which may slow vegetative growth, but does nothing at all to promote "bloom". Ray has talked about the history of this in another thread awhile ago...

My take on it is if you want less growth, just cut back on the fertilizer. But orchids (and especially Phals) are growing vegetatively pretty much all the time, and so need fertilizer all the time. Orchids that need a rest period (such as some of the deciduous Dendrobiums) don't want any fertilizer at all during that time. But Phals don't have a "down" time. (Not only are they always growing, they're also always
rooting which is why they don't care when they are potted, even in bloom) I totally agree on the 1/4-1/2 of whatever it says on the bottle. Orchids grow slowly and so have very low fertilizer needs.

I also doubt the "no urea" bit... orchid roots do contain bacteria that can break down urea (and other organic nitrogen-containing compounds) This is reasonable... in nature, they get their fertilizer from the breakdown products of detritus in the trees above them, which washes down. I think that I can guarantee that neither ammonium ion NH4+ nor nitrate N03- ions are present unbound in that "bath". Clearly orchids CAN utilize organic nitrogen because that is what they get in nature.