You should wait to turn on the overhead lights until they break the surface.

As an aside, you are going to have to remove the dome when the coles and tomatoes come up, even if the peppers are not up. The peppers will probably take a week or so longer than the others. The coles will probably be up in 3-4 days, tomatoes 4-7 days and the peppers (even with the heating mat) could take up to 3 weeks, depending on your variety.

Try to keep the lights (if they are CFLs) as close as possible to the plants and on for about 16 hours/day. 2-3 inches from the tallest leaf is standard. You may need to adjust things from tallest to shortest and raise on side of the lights higher than the other as they grow.

Thanks for that information. When should I turn my heat mats off. Should I wait until after germination,or wait longer. I also read that broccoli,cauliflower and brussel sprouts dont require bottom heat.

The peppers NEED bottom heat. They really won't germinate without it. If possible, remove the bottom heat from the coles, leave it under the tomatoes and peppers. Remove the heat from the tomatoes when they sprout. Keep the heat under the peppers until they germinate.

Reasoning: Heat promotes growth. The artificial light set up will lead to leggy (tall, thin, weak stems with very few leaves) plants. Keep the room as cool as possible, and remove the heat source as soon as germination occurs, for stockier, hardier, healthier plants.

Hi- I have my tomato, pepper starts, artichoke, rhubarb, kale and lettuce under grow lights on a heating pad and have been leaving the lights on 24/7. Will this create any problems? Any suggestions?

Thanks for the help!
Pluck

i think you should have your lights on 16 hours a day (8 hours off). plants need rest too.

I keep my lights on 16 hours a day normally, but if I want more heat (I use the ballast to bottom heat tomatoes and peppers), or if a seed just germinated, I will leave the lights on all night once, and then go back to the 16 hours of light.

I like to give the seedlings the most light possible when they first germinate, because leggyness can't be undone. My plants are healthy, stocky, and seem to be quite "happy".

I would not leave the lights on 24/7, but an occasional extended period of light shouldn't be a real problem for them.

There's a thread in this section where a guy did an experiment with 24/7 vs. 16/8. Here's a link to it.

Mike

Thanks Mike!

After reading that thread...I won't be turning off my lights! I'm willing to risk it!

I want my peppers and tomatoes to produce early, and if running the lights 24/7 does that for his peppers, it can do it for MINE too! It also frees me up from plugging and unplugging every day!

Thanks again!