no, just the 2 mats that I bought originally.

So, does the probe go in the soil and if so whereabouts in the flats do you put yours for best results? Sorry for all the questions, but keeping even temperatures has been a real headache with what I have.

I make a 4 inch container with soil and put the probe in there. Soil in that container is 3/4 full and I water it same as the flats, seems the flats are to shallow to get a reading.. What are your growing, may I ask?

Mostly annuals, petunias (LOTS of petunias), alyssum, and other misc bedding plants like lobelia and blue pimpernels. Along with starting tomatoes, lettuce, spinach and onions. Sometimes corn and squash. Our growing season here is so short that pretty much anything I want to grow needs a jump start. I like Lisianthus and Lavatera trimestris, too. My main problem with regulating the heat mats is with things getting too hot.

This year try putting your probe in the 4 inch container with soil. Might help.

That sounds like a good idea. Now if I can just remember...