For what you are growing, you do not require extra bottom heat. Some seeds will be little slow at your temperatures, so look for the warmest place in your house. Al

I agree with Al to a point. Is a heating mat required? No. The seeds will still germinate - eventually.

Is using one usually recommended? Yes. You will get improved numbers of seeds germinating and much faster germination.

Do don't confuse air temps with soil temps. For germination, it is soil temps that is important, not the air temp. Soil temps are normally 10-20 degrees lower than the ambient air temps. For example, pepper seeds germinate best in soil temps of 80-85 degrees. You cannot warm your soil to that temp without a heat source.

So to obtain the best results, the use of heating mats, or at least some source of supplemental heat, for germination is normally recommended for indoor seed starting.

Dave

PS: this is a frequent question here and the search will pull up previous discussions about it if you want to read through them.

Thanks for the information. I decided to go with a 20"x20" heat mat to germinate my seed flat.

Also, once my seedlngs have germinated and become large enough to move out of the flat and into bigger (temporary) pots, they don't need a heat mat any more do they? Heat mats are just for germination right?

Thanks,

Matthew

Badmajon-
I agree with diggit. It's not necessary but the plants will get a much healthier start because their root systems will groow alot faster and stronger. Here's link that might help.

Here is a link that might be useful: Make Money Gardening

Heat mats are just for germination right?

Exactly. Immediately, as they germinate, off the heat, cover (if used) off, and under the lights ASAP.

Dave

Just a note here - a heating pad bought at CVS or Walgreens will cost under $20. One in a nursery - lots more. I only use mine for germinating pepper seeds.

I'm still using the heat from the fluorescent T8 lights just above the clear lid with excellent results. Some results in 48hrs. Heats the soil nicely...Jack

The often quoted difference of temperature between air temp and soil temp, led me testing over the last couple of days. I already had tested soil temp when on a heat mat and found no difference between heat mat temp and soil temp. I have an incubator that allows me to set air temperature very accurately. I put a container of seed starting mix moistened, with a thermometer in it. After 12 hours the mix was 3 or 4 degrees cooler than the air. After 24 hours it was still the same. So the soil IS cooler than the air, but not by much. Al

That is a good point Al but keep in mind that is in a confined space and a relatively small one at that with a limited volume of air.

The bigger the confined space - ie: a set of shelves enclosed in plastic, a small green house, etc. - the bigger the air volume to be heated the greater the difference in temps.

Imagine the difference between the air and soil temps in the average living room much less the average basement.

Dave

My experience tells me that if you want germination in under 10 days from peppers a heat mat is a must. Other veggies - Not.

My pepper seeds (which I save from year to year and some are 10 yrs old) germinate in 4-6 days with bottom heat. That is all I use my heat mats for.

BTW I suggested that a heating pad from a pharmacy was cheaper than a mat from a nursery and I was right but the one I just bought for $17.99 has a automatic shut-off after one hour. We rigged a stone with velcro to fool it but if you are worried about such a thing, look and see if it has that shut-off feature.