Making Potting Soil

Make Your Own Potting Soil to Start You Seedlings

By Barbara Fix, Researcher & Writer for Lipscomb Enterprises Inc.

In the gardening world, potting soil is one of the first steps to growing healthy, happy plants. It’s available just about everywhere; hardware stores, landscape and nursery suppliers, and even the local grocers. But instead of grabbing a bag a bag of commercial potting soil, have you ever thought about making your own?

There are valid reasons for making your own potting soil. Pregnant women should avoid coming into contact with commercially prepared potting soil that contains fertilizer, pesticides, or insecticides because they contain ammonia and sulfur dioxide. Studies have shown ammonia and sulfur dioxide can cause birth defects. Commercial potting soil has led to the illness of cats and dogs, and in the worst case, death when ingested. Even organic potting soil that contains cocoa mulch is toxic to cats when ingested and more so with dogs. There have been numerous cases of deaths with dogs attracted to the smell of cocoa mulch who ingested it, causing death. .

The goal when making your own potting soil is for good water rention that also drains well so your plants don’t suffer from root rot. It should also provide plenty of nutrition so you end up with the healthiest plants possible.

Organic potting soil can be made with equal parts soil and compost (see our article The Importance of Compost on our site for instructions on how to make compost).

Most backyards soils will be too compacted and full of weed seeds to safely use it for potting soil. It may not drain properly, and worse, can develop a “crust” that won’t allow seedlings to punch through the surface. Also, untreated soil can lead to diseases in seedlings.

To avoid issues with unpasteurized soil, you can pasteurize small quantities in your oven, but for large amounts of pasteurized soil, you may want to purchase it at a landscaping or nursery supplier close to you. To pasteurize your own soil, put slightly moist garden soil in a pan. Insert a food thermometer in the soil. Cover with a lid or tin foil. Place the covered pan of soil in a 250 degree oven until the soil has maintained a temperature of 180 degrees for ½ of an hour. Be sure not to overheat the soil, or ic can damage the structure of your soil.

Now on to the “Recipe”

1/3 equal parts mixture of mature compost and pasteurized soil

1/3 Sand

1/3 Peat Moss