...you need to use something a little more 'blue-y' for the veg/growth stage. I'd keep the HPS around, but go nuts buying the little 100w equiv/26w actual 6500k daylight CFLs. A box of six goes for 20bux up here, so you could get a dozen or so hung tight around your plant(s) if you wanted for like 50bux or less.

And if you get the right ones, 12x26w=312w actual consumption, not too bad...
12x1750 lumens, tho... equals 21000 if you get 'em /close/ enough...

Muah hah hah (tm)

(c)C :chainsaw: