The Best Soils for Starting Seedlings

Sterile Potting Soil

• An easy approach to starting seeds is to use potting soil, available at most garden centers. Choose potting soil that has been sterilized, to avoid the likelihood of disease-causing organisms. Soil should be lightly moist but not wet when sowing seeds, and the seed should be placed just under the surface of the soil. Allow the soil to dry out slightly before watering, and use a misting technique to avoid flooding the seeds.

Commercial Soil-less Mixture

• Using a commercially available soil-less mix is a good option, according to the Texas A&M's Extension Service website. These mixtures are sold at garden centers and are free of microorganisms and weed seeds; they also hold moisture, drain well, and are lightweight. However, they are totally dry when purchased and may be difficult to hydrate. A good approach is to add some water to the mixture in a plastic bag, mix well and then allow to hydrate overnight before use. Fill containers or flats with the moist mix and then insert seeds just below the surface. Keep the mix moist until seeds germinate.

A Custom Mixture

• The Extension Service website states that a home gardener may easily make a custom mixture for starting seedlings. Mix one bushel of horticultural grade vermiculite with one bushel peat moss. Add to this 5 tbsp. superphosphate crystals and 1 cup standard garden fertilizer, for example a 5-10-10 balance. These ingredients are available at most garden centers. Mix well and add a little water to minimize dust. When planting seeds, add enough additional water to make the mix uniformly moist.