I have a older plant and one young plant. I'm not using a grow box or tent. Just sits on some big containers and have lights on top. I started off with one plant and 2-25w 6500k cfl's and put them on a 18/6 schedule. Now it's been 28 days for the older plant and a week or so more less for the younger plant. And I bought 2-45w 2700k cfl's and put the older plant into flowering. Put with these 2 lights (45w) it's not enough but it's seems to be fine for my setup/walk in closet. And temp. Is fine. I am in Az. And it's getting warmer here so it's just right in there for the plants. I'm gonna buy either 2 more 45w's or one. Idk yet.
I guess it just depends on ur setup and where u live. But either way u wanna have atleast 4-6 low watts or I would say 4-5 bigger watts. I got the 45w cfl. From walmart. For $8 each I think. But with those two running I can tell the difference in temp. And plant growth. Check out my thread @ https://www.rollitup.org/newbie-central/320464-n00b-gr0w-pic-check-out.html