right now I have 2 t5's with some seedlings growing underneath it. I'll be upgrading my seedling/clone room with a 4 bulb tek-light (20,000 lumens). You want an hid to grow your plants. But if you only have flourescents you can still grow some weed, it will be a little sub standard. I dont think Ive ever heard of somone growing a crop under 2 t5's though.