I keep my heat on them at about 83F until they are a 3-4" inches tall. I use floro tubes too. From what I understand, the, heat not only aids in germination, but also root development. Then they stay at room temps under lights until it is time to go outside. If I was a little behind in my growing schedule, I might hold the heat on them longer to aid in growth but after a month or so, I don't think it is as helpful as early on. Besides, just common sense tells me that if I keep them at 85 until time to go outside, it might be a big shock for them to all of a sudden get heat with much lower temps both in the soil and above. I don't know why topsoil temps are at the end of May but I would guess that a foot down, they are still under 50 degrees and nights that time of year can easily dip into the 30's.
That is my though process anyway.
Bruce

This post was edited by esox07 on Thu, Jan 17, 13 at 16:21

After seeds sprout I do not use heat, just under T12 lights, room temp in a basement. My plants do fine.

In the pic from last year the far right peat pots were planted same time as the ones in the middle, death to the peat pots horrible. The ones to the far left are the replacement for the peat pots started a few weeks after.

Mark

I never liked those peat pots. They don't last long enough sometimes before the start to break down. Then they are supposed to just be transplanted with the seedling but I have found that they dont break down enough to allow the roots to expand beyond their walls until well after they are completely root bound. I use plastic and just keep reusing them each year unless they have cracked. It seemed harder to manage moisture levels with peat pots as well.
Bruce

Bruce:

" Besides, just common sense tells me that if I keep them at 85 until time to go outside, it might be a big shock for them to all of a sudden get heat with much lower temps both in the soil and above."

Yep. I've made this mistake(but survived) with other veggies by not hardening off.

Kevin