In my experience with Coast of Maine Stonington Blend is that it is too hot for seedlings. I had this problem my first grow, and now start seeds in some used soil that has been depleted. I start out in 2" peat pots and then transplant into 1/2 gal pots with Stonington Blend on the bottom 1/3 of the pot and then I mix some of the regular soil with the Stonington 1/2 and 1/2 and transplant into that, which is on top of full strength soil. By doing it this way, I gradually introduce them to full strength soil when I put them in the 5 gal pots. Hope this helps.