Quote Originally Posted by GRB.4.Life
You should be alright for flowering simply with that HPS. Don't use "soft" white bulbs. They don't really put out a usable Kelvin for the plants. I could be wrong though, check the Kelvin rating on the soft-whites...

You want your Kelvin ratings to be about 6500K for your cool spec and 3000 for your warm spec.
You're wrong in the first paragraph, but you do have your facts straight with the kelvin ratings. HPS lamps are in the 2200K range, daylight MH lamps are about 5500K.

I have not flowered with CFLs myself but everything I have read supports what I said. Soft whites are around 2700K a lot of the time. Cannabis wants more blue light for veg, and more red light for flowering. But having some blue and red light present at all times is great, which is why I wouldn't suggest replacing all the 5500-6500K bulbs, just a couple of them.

http://boards.cannabis.com/closet-ca...seed-grow.html
http://boards.cannabis.com/indoor-li...ussion-13.html
http://boards.cannabis.com/closet-ca...-question.html