Pasteurizing soil in the oven can create an odor some people find offensive. Clean clay pots can be sterilized by baking while the soil is heated. Pots can be sterilized by soaking them in a solution of one part chlorine bleach and nine parts water. Rinse, and allow the pots to dry thoroughly before filling them with soil. An alternative is the purchase of new, plastic or fiber, disposable trays or flats.
Plants grown in peat pots suffer little setback when transplanted into the garden.
Use a loose, well-drained, fine textured soil mix that is low in nutrients. A suitable mix is equal parts of pasteurized garden soil, sand and sphagnum peat moss. Commercially prepared mixtures may also be used. Fill the containers about two thirds full with soil. Level the soil and soak it thoroughly.