Homemade soil mixes should also be pasteurized before use. Pasteurization destroys weed seeds, insects, and disease pathogens in the soil mix. To pasteurize, lightly moisten the soil mix, place in a shallow baking pan, and bake in the oven at 180 F for 30 minutes. Allow the soil mix to cool before using or storing in a plastic bag. Various containers can be used to germinate and grow transplants.
Gardeners can purchase flats, trays, pots, compressed peat pellets, and other commercial products.
Cut-off milk cartons or plastic jugs, paper cups, and egg cartons can also be used to start seeds. Previously used flats, trays, and pots should be cleaned and disinfected before use. Wash the containers in soapy water, then disinfect them in a solution of one part chlorine bleach and nine parts water. Holes should be punched in the bottom of milk cartons, jugs, paper cups, and similar containers to allow for drainage. The size of the seeds largely determines the type of container and sowing method.