The trays are 21X11, and each cell is 3/4 inch wide, and 1 1/2 inches deep. still, I have to keep an eye on these and several need watering every day. I imagine a tomato, or pepper, or any other plant in a cell this small will be transplanted according to size. Many of my peppers are just sprouting now, and I think that somewhere between 3-4 weeks they will have a fair amount of root structure developed to transplant. What I get to wondering is where I am going to put all of these plants if most of the seeds sprout......I've tallied over 1300 seeds planted! I hope a lot of people will buy plants! HeHe