Last year, I tried starting my tomatoes in Jiffy Mix. As you can see in the picture at the top, I got tiny scrawny, purple seedlings. They were 2-4 inches tall. The picture on the bottom shows my tomato seedlings this year that I started in peat pellets. They are 8-10 inches tall. Both photos were taken when the seedlings were about 6 weeks old. From now on, I'm going to stick with peat pellets.