These grow pots and trays are made of recycled paper pulp are fully biodegradable. Sow a seed in each pot and when the seedlings are big enough they can be transplanted to the garden. The paper pots will dissolve naturally in a short time and the roots can expand further in the soil. Ideal for growing vegetables, herbs and flowers. Comes in 2 different size round pots, medium round 18 pack (3.2") and large round 12 pack(3.9"), and 2 different sizes of trays, small tray 3 pack (6.3"x 4.7") and large tray 4 pack (10.8" X 3.5").