Heat mat during germination

Heat mats are really only for use when growing in soil, otherwise they can cook any seeds in direct contact with the heat mat. Remember too, not all seeds will germinate. When starting them in paper towel, it is far more important to have a close to as a constant temperature as possible, although this is not overly critical, and to keep the seeds moist and not wet. I have never soked my seeds in water in over 35 years, seeds actually need air exchange to germinate properly, just use the moist paper towel and even in winter when temps indoors are 10-12 degrees centigrade, germination is still 98%+, while ever the seeds are fresh, but they may take a day or three longer than if the temps are 18-25 degress C. Hope this helps, Organoman.

Most heat mats will not overheat your seed. It only helps with germination rate and is usually not needed. If your seed is more then a year old it would help, But for newly bough seeds you should have no issues germinating them.

Never used a heat mat, always gone with Paper towel in a dark temp steady area.