Types of Soil Used in Nurseries

Pasteurized Soil

• Garden soil isn't suited for nursery container plants because of its weight and the possibility of contamination. Outdoor soils contain helpful microbes essential for providing aeration and breaking down essential nutrients. When placed indoors, however, these microbes can potentially spread disease throughout an entire greenhouse crop. When using small amounts of garden soil, take care to pasteurize the soil. Large commercial operations heat soil for nursery mixes. You can do the same at home by placing soil into a shallow baking tray. Heat the oven to 250 degrees Fahrenheit and heat the soil until it reaches 180 degrees for 30 minutes. Temperatures exceeding 180 degrees destroy soil structure. Use this soil in combination with other ingredients to provide your plant with a well-aerated and nutrient-rich growing environment.

Cornell Plant Mix

• Soil scientists from Cornell University created a potting mix using sphagnum peat moss, vermiculite, medium fine perlite, ground dolomitic lime, superphosphate, 10-10-10 fertilizer, iron sulfate and potassium nitrate. This recipe provides foliage plants with optimum pH levels and essential nutrients as well as a light medium suited for root growth. This mix is used in commercial nurseries, but home growers can create the mix as well, provided they have access to all of the ingredients.

Clemson Plant Mix

• A simpler but effective soil mix is one Clemson University soil scientists developed. Like the Cornell plant mix, the Clemson mix does not contain garden soil, but when all the ingredients are combined, it provides indoor containerized plants with an effective growth medium. Mix two parts soil condition grade pine bark with one part peat and one part sand. Depending on the intended plant's pH needs, you may need to add dolomitic limestone. Clemson horticulturists recommend feeding the plant with 20-20-20 fertilizer after every seventh watering.

Tropical Plant Mix

• Tropical greenhouse plants have different nutritional needs than other plants. A base mixture suited for tropical plants includes Canadian peat, sand, cypress sawdust and perlite. The amounts of each, as well as additional nutrients and supplements, is determined by the specific plant's needs.

Organic Soil Mixes

• Certified organic soil mixes contain many of the same elements and ingredients used in other commercial mixes, but they are produced and harvested from certified organic sources. Organic soil mixes contain clean topsoil, sand and compost. They do not contain any synthetic materials.