I grow 2-3 at a time. The last couple of grows I have been using 8 bulbs. Four 23w 5000k bulbs and four 23w 2700k bulbs for veg. Then I would use two 23w 5000k and six 23w 2700k bulbs for flower. It worked fine but I noticed that it was taking for ever for the plants to mature, and the yield could be better. During veg all was fine. Now this grow I am doing the same as I have been for veg, but for flower I am going to continue to use the two 23w 5000k bulbs, but I am going to bump the reds up to six 40w 2700k. I had my last WW grow in flower for 12 weeks and the yield was decent but it could have been better. Luckily I am a fairly patient person.