What kind of soil should I use?

All About the Soil

What is potting soil?
Potting soils are soil-less mixes used as the medium for growing plants in pots. They are soil-less to make them lighter in weight and they are close to lifeless in terms of soil microorganisms as houseplants are prone to soil rot. Some potting soils are also steam sterilized. Potting soils usually don't contain significant quantities of nutrients. Their primary function is to hold air, water and any added fertilizer.
A good mix must stand up to repeated watering without losing structure and still be quick draining. A good do-it-yourself recipe for potting soil: 4 parts by volume peat moss, 2 parts well composted plant material, 1 part vermiculite, perlite, or sponge rock, and 1 part sharp sand or grit.

What is planter mix?
Planter mixes are primarily soil amendments based on composted materials frequently with added balanced fertilizers. These products are not closely regulated and may contain materials you don't want in your garden. Some planter mixes contain composted sewer sludge which may contain high levels of heavy metals. Soil is better amended with compost from known sources.

What is propagating mix?
Propagating mix is a soil-less mix used strictly for propagation. It contains no nutrients. A typical recipe for a propagating mix for green stemmed perennials might be 1/3 sponge rock, 1/3 peat moss, and 1/3
grit. A typical recipe for a propagating mix for woody stemmed perennials like roses might be 1/3 white peat moss and 2/3 regular peat moss.

What's the best kind of soil to use in containers or planters?
Soils used in containers and planters need to be both water retentive and well draining. In practice, this means the need for a high organic content. The soils should also be free of any pathogens. A good loam with about 1/4 clean compost would seem about right.

What causes certain soils to smell foul?
A foul smell indicates anaerobic decomposition. The soil doesn't have enough air. It can be corrected by adding additional organic material and turning it into the soil.