Plastic food-grade tubs are easy to make into Winter Sowing containers. They are usually filled with frozen whipped topping, soft-spread margarine, cottage cheese or yogurt. After use, wash the container and lid well, you will need the lid so do not throw it away. The photos on this web page show a whipped topping tub.
Label the base of the container with duct tape and a permanent marker. You can also add a secondary label to the top of the container. The underneath label will never bleach out from strong sun.
Press the knife into the soft plastic by the base to make a drainage slit. Four slits should provide enough drainage.
Most plastic tubs have a soft plastic wall that is easily pierced with a sharp-pointed small knife.
You do not want to cut through the rim, it must remain solid and tight. Outline a cutting area inside the rim. In its center make a slit with a small sharp knife.
With scissors entered at the center slit, cut to and around the outline to remove the center of the lid.
Fill container to about a three inch depth with your favorite potting soil or sowing medium. Moisten soil, sow seeds, cover as needed with sowing medium, then drape the top with clear-plastic wrap.
Snap on the lid and snug the plastic wrap tight. Gently poke in a few slits for ventilation. The photo shows a slit about every inch or two.
This is a completed lid. The center has been cut away and the rim is intact.
WinterSown always recommends the use of food-grade plastics for sowing containers.
Children should be supervised when making their Winter Sowing containers.