I have a buncha LED bulbs at my house for general lighting. most of them i ordered from dealextreme.com or meritline.com big purverors of china manufactured products. just search "led bulb" on either site. I cant even grow a front lawn, by no means do I have a green thumb but i see issues with LEDs because

A - they are COLD, they dont seem to generate any heat at all, and if i recall correctly plants need heat (unless there is another heat source, but in nature the light source is the heat source)

B - Manufacturing consistency. I have ordered lights in groups and individually, it dosen't seem to matter. I can tell different "batches" make different light

my 2c - maybe worth less