Fill a 1-gallon container with sphagnum peat moss. Peat moss is an ideal additive because it helps the soil retain water. Pour the sphagnum peat moss into a 5-gallon container.
Fill the 1-gallon container with vermiculite, perlite or coarse sand. If desired, you can also blend these together. Vermiculite, sand and perlite improve drainage in plant containers. Pour the vermiculite, sand or perlite into the 5-gallon container.
Fill a 3-gallon container with organic material, such as peat. Sawdust and humus are also ideal. Pour the organic material into the 5-gallon container. Thoroughly mix the contents of the 5-gallon container.