Help! Questions about heat strips under seed trays..

Hi. I cannot recall any of the specifics about using a plug-in heat strip under my tray of peat pots holding various kinds of seeds (sunflowers, snapdragons, lettuce, carrots, annual daisies, etc.) Do I keep it plugged in around the clock or just for a few hours a day? All night? Do I "crack" the clear plastic lid to keep it from getting too hot? As you can see, I haven't done this for quite some time and would appreciate any thoughts or experiences anyone has had. Thanks!
Louise

I guess it depends - do you have a thermostat or any way of telling how warm the tray is? Generally speaking (& anyone can jump in and correct me here) it seems most seeds germinate at about 70 degrees. That's where I had set my thermostat and left the heat on 24/7 until germination occurred, and then I removed the lid to allow air circulation - but more for humidity control than heat.

HTH!

Hi Pagancat.....and thanks for your response. I don't have a thermostat.....it's just a simple strip that I placed under the generic black seed tray with the clear plastic cover. It may not have been smart to put so many different seeds in the same tray at once....I'm sure their germination rate will be different. I haven't done my seeds this way in such a long time, so I appreciate your thoughts as well as those of anyone who may have some too.

I agree with Pagancat, sounds like pretty much what I do with my seeds. I always leave my heat mat on 24/7 until the seedlings germinate. If you bought one specifically for seed starting you may not have to worry too much about the thermostat, but if it was designed for some other purpose then a thermostat may be necessary. And I crack the lid if there's too much condensation, but it's to control humidity (if it gets so hot in there that you need to open it to reduce the heat, you definitely need a thermostat)

Thanks, Liz. How will I know if it's too much condensation? I'm not sure how much is too much.

If it's like a fine mist inside the lid that's OK, but if it's starting to collect into larger droplets then that's when I usually vent it a bit.

That's very helpful! Thanks so much!
Louise