The germination medium should be damp before it is placed in the container. Fill the container to within about 1/2 inch of the rim. Seed should be scattered uniformly across the surface, or sown in rows at the rate of 10-20 seeds per square inch. You may choose to give each seed more space, depending upon seed size and length of time small transplants will be left in the container. Seeds sown too thickly will result in excessive competition among plants and spindly growth. Small seeds, such as petunia and snapdragon, should be left uncovered. Cover larger seeds with a thin layer of germination medium. Finely pulverized sphagnum moss has fungicidal properties and would be ideal for covering seed if it is available.

Most seeds will germinate in either darkness or light. Sunlight or illumination from a lighting system will be satisfactory for those seeds that require light for germination. Laying a newspaper on top of the container will provide darkness required by other seed. Special needs regarding light and dark treatments should be stated on the seed packet.