For big, stocky transplants. 3 1/2 inch square by 2 7/8 inch deep. 18 pots fit in a standard 1020 tray. Great for bottom watering so the seeds do not get dislodged. These medium, plastic, black seedling pots measure 4 inches by 4 inches and the dirt line goes up to 4 inches with an extra inch of height. They are perfect for transplanting small seedlings to so they can get a bit bigger before putting them out in the garden. I use these in many of my greenhouse to grow seeds in as well. They are reusable and sturdy. They last over several seasons before cracking.