As much light as you can/want to give, up to the point where you also give too muhc heat.
I agree that T5s are outstanding for young sprouts. I run my seedlings under T5s until they have 5 nodes and are ready for a transplant into something larger than a 3" pot. After that, a nice MH with the outstanding hort blue bulb... mmmm!!! Juicy!
stinkyattic Reviewed by stinkyattic on . Too much light?? I have 7 sprouts ranging from ~1-2inches currently under 300w equavalint cfls (i think they are 23w or something) anywho I also have a 400w hps that im going to use, however can you have too much light for a seedling? I know you can with clones b/c they don't have the established root structure and they lose water, but is this also true for seedlings?? i want to give them the best and brightest 2-3months of their lives, but not over do it. anyone?? Rating: 5