Should I buy a heat mat for my seedlings?

General    NC

I am starting to make plans for my vegetable garden this year. I would like to grow peppers, lettuce, peas and maybe eggplant. I plant to start my seedlings indoors soon and I wondered if I should buy a heat mat for my trays. I have some space in the basement to set up my seedlings but my germination rates were not great last year, about 70% max. Do any of you use a heat mat? Would it help?

Posted by: Ann McIntyre (1 point) Ann McIntyre
Posted: February 4, 2013


Optimal germination temp for many vegs, including peppers, is 86F. But peppers will germinate at lower rates from 68 to 95F. After they germinate, they like temperatures around 70F. Eggplants need it a bit warmer, maybe 90F for the highest germination rate. So if you want the fastest germination and highest germination rate, you will need a heat mat or some other source of warmth (a sunny window,* a radiator, etc.). Once the seeds have germinated, they prefer cooler temperatures (50s min., 70F best) and need light.

Lettuce will germinate optimally at 68F (range is 41-83F) and grow best between 60 and 65F. Peas also like cooler temperatures, optimal is about 80F (range is 45-90F).

The temperatures come from the charts in the catalog from Johnny's Selected Seeds.

Once the seeds have germinated, they need light! Do you have fluorescent lights?

*I've successfully germinated pepper seeds without a heat mat or lights. I moistened a paper towel, put some seeds on it and folded it over, and placed it all in a sealed and labeled plastic bag. I placed the bag in front of a south-facing window where it got direct sun for several hours. I got pretty good germination of all 6 varieties within a week or so. I then grew the seedlings in front of the sunny window.

I've also grown tomato seeds in a cold frame. They grew very slowly, because though the cold frame was warm in the daytime and usually needed to be vented to keep from overheating the seedlings, nighttime temperatures were still in the 40s.

Posted by: Tanya in the Garden (128 points) Tanya in the Garden
Posted: April 9, 2013

Your basement should be fine I would think and a heat mat may help your plants along but is not absolutely necessary. Is it possible that some of your plants were killed by damping off or due you think it was more of temperature issue? I am obviously further south but I find seedling do just fine without a heating mat

Posted by: Simon (2 points) Simon
Posted: February 4, 2013

Is your basement insulated? At this time of the year I find my un-insulated basement in Central PA to be very cold hovering around 45F. Maybe not so cold where you are? If you do put them down there maybe keeping them off the floor on a table would help keep them a little bit warmer.

Posted by: David Hughes (54 points) David Hughes
Posted: February 5, 2013

Ann McIntyre commented,
David, thank you for your response. Yes, my basement is insulated and I have tables that I can prepare the plants on. It has worked very well for others that I know here but I'm not having huge success. Perhaps I just dont hav the touch
over 7 years ago.

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