i used one this yr for my starts(only 6) it worked great untill they were about 5 in tall and had several sets of leaves. i had a reflector(dome type) bought for like 6$ and i think it helped. get the largest one you can find it stays cool. mine was a 26 watt. there is a story here if you look for it a guy(cant remember) built a rubermaid box with 6 of these lights in it and grew his plant to maturity in it.