I have started seeds under lights for the first time. I seem to be having excellent success (took advice from my in-laws and set up the lights close to the hot water tank and furnace for warmth). This leads to my question. I am using a tray with 24 two inch cells and a clear plastic cover. It has only been a little over a week, but many of the seedlings have grown to a size that they are hitting the top of the plastic cover. After germination, is it s good idea to leave the top off?
Many people do removed the cover at the first sign of germination. Too much humidity can promote damping-off. I keep my humidity dome on a little longer, but I've got a few little holes poked in it for ventilation.
If your seedlings are leggy (tall without having many leaves yet), you might want to move them closer to the lights. Having the top leaves within an inch or two of the bulb will make for nice, sturdy seedlings. Check my other articles on setting up light shelves and preventing damping-off for more details.
Sounds like you got great germination with your setup. Good growing! :-)
I followed your instructions for setting up a set of lighted shelves. My shelves are composed of wire, so I tied the flourescent fixture to the bottom of one shelf to illuminate the shelf beneath it. I used a chain and "S" hooks to lower or raise the light from the plants. I kept the shelf set in front of a window and used ordinary flourescent fixtures (not full spectrum bulbs). I have successfully grown tomatoes, canterberry bells, wave petunias, impatiens, and datura.