I had some seeds in a paper towel with no heat. sits around 78* in that closet. So I put them in soil today, little 3 oz. cups. In the dome without the lights on it sits right at 78*. I've had no problems before really, but of course I read where you should use a heating pad. Man, if it's sitting at 78*, they germed and are now in soil at 78* that should be sufficient right. i am assuming that turning on the seedling mat would put it over 90*.
Yea, they should be fine at 78. I normally shoot for around 80 degrees. The heat mats really only raise the temp about 5 to 10 degrees above ambient. If your area is warm enough they aren't required but seem to help maintain even temps. I prefer to use one because I keep my ambient temps in the grow area around 70 to 73. The heat mats are better for starting seeds in plugs or cubes.