There are numerous quality container mixes available for purchase. Many include desirable additions such as wetting agents that make it easier to water when the pot dries out, water-absorbing crystals that retain more moisture in the pot, and slow-release fertilizer that supplies constant nutrition. You could add all these extras to your own mix, but you may have to search a bit to find them. These convenience factors come at a price.Commercial mixes usually are more expensive than a basic mix you concoct yourself. A fairly standard recipe for a medium-textured mix is 50 percent (by volume) peat moss, 25 percent coarse sand or perlite, and 25 percent ground pine bark. Variations on this basic mix include 2 parts peat moss, 1 part perlite, 1 part coarse sand; 1 part peat moss, 1 part sand, 1 part pine bark; and 1 part peat moss, 1 part pine bark, and 1 part perlite. Experiment with these ingredients until you come up with a mix that suits your needs.