Turn it off after germination. You'll have shorter stockier plants grown at 55-65 degrees.

Thanks, Taz.

Rain

no need for a hot tushie
after germination

Okay, off it goes as soon as my slacker Stupice seeds sprout.

Rain

Just use it for those seeds. No need to make the other plants leggy while waiting for seeds that may never sprout. Not saying the seeds are bad, just saying you're hurting the other plants in the process.

I use a heat mat under my trays that I use for germinating seeds and what I do after they have sprouted is move them to another tray that is not over the heat mat. If I have a low germination rate and I leave seedlings on it more than 24 hours after germination in hopes that the additional time over the warmth will coax the slackers to sprout, I see that the germinated seedlings are already exhibiting a tendency towards legginess.

Your mileage may vary.

Betsy