Keep the lights a couple of inches from the plants. I grow using T8 Fluoro's and the plants seem to do well when the light is no more than 2" away.

Are you starting with clones?
Plants start growing when vegging. Did you mean how tall should they be when entering flowering stage? If so that's basically up to you. How tall do you want them to be at harvest? They can grow twice as tall during flowering, even taller than that is not unheard of.

Between 18/6 and 24/0 is fine for vegging plants, diff peeps set to diff times. Fresh clones need diff lighting though...

6500k for vegging at roughly 2000 lumen per square foot
2700k for flowering at 3000 lumen per square foot

BTW get a fan for the plants if you dont have one already, they'll need it.
Slevinkal Reviewed by Slevinkal on . Please Help ! New to growing and have a few questions . Hello , im new to this site and new to growing. Im attemping for the first time to grow. Im looking to only have about 4 plants flowering at a time. Im useing Fluro to grow. I have a 4 ft Balist with two T12 40 Watt bulbs (Think its about 3000 Lumens per bulb, and color temp is 6500k i believe) , I also have 6 CLF's . Two putting out 1600 Lumens and two putting out i think 1000 or so lumens these all have a 6500k Color temp. and i also have two 1000 Lumen 2400k bulbs. I heard these were good Rating: 5