Bottom heat is the answer. If you can set them over a heat source which will warm the soil to 78°F or so the seeds will be popping up FAST!

But isn't it kind of early to be starting tomatoes and cabbage in Pennsylvania?

Jim

The tomatoes are a test...The ambient temp where they will be growing is about 70 degrees in the day and 50 degrees at night, so the cabbage should start off slowly. If they go gangbusters, I have some cold frames that will be in the garden where they grow, followed by row covers.

I am trying to push the limits of my garden this year to sneak a few weeks at the start of the growing season. (It's been a very long winter!)

I start tomato seeds about March 31st here......and that is plenty early here.

If you use a heat mat under the seeds you will see them sprout in 2 to 3 days. I was amazed the first time I tried germinating with a heat mat.

Here is a link that might be useful: Win Free Garden Stuff