Why they don't ramify?

give it time.. she's just begun. Cree CXB3590 are excellent cob led -- you can do much better, nowadays. umol/s umol/s * J^-1 These are the specifications you need to compare lights -- in addition to the footprint they have - i.e. how many units you need for your area(s). As far as led at this moment in time -- Samsung LM301B (H or B, but both exactly the same) diodes are teh most efficient thing you find out there... at .7A you'll be around 3umol/s*J*-1... high end hps are 2.2? leave them in the dust with a better spectrum and significantly more efficient... wasting electricity on heat for no reason. QBs or strips are awesome options. If they mix in some red (660nm) even better. you are armed to compare quality lights... go get'em! umol/s (how many required per your area -- e.g. if a m^2, that's actually your "PAR" otherwise mist be relative to it with a little applied algebra) and efficacy umol/s*J^-1