Master Gardeners Corner: Bagged soils

What is the difference between potting soil, garden soil, and other bagged soils? Please be aware that not all packaged soils are the same. There are generally some basic differences between the types of soils, and in the different types of similar soils and ratios of contents.

Note that there are no legal definitions for the various types of bagged soil, so it’s important to read what’s in the bag.

Potting soil – Bagged potting soil usually does not contain dirt. Generally used for container gardening, it usually is a mix of peat moss, composted pine bark, and some other organic materials. Water drains out from potting soil easily.

Garden soil – Garden soil usually contains a percentage of dirt in it. It retains water and is used for in-ground planting.

Topsoil – Topsoil is technically the upper ten to twelve inches of soil. Thus the natural topsoil ranges depending upon location. As stated earlier, because there is no legal definition for bagged topsoil, what’s in the bag can vary greatly. Bagged topsoil can be clay or sand or loam or other types of soil mixed with compost and or fertilizer. Never make any assumptions regarding what’s in a bag labeled as “topsoil.” You need to read the contents on the bag.

Seed starting mix – These mixes generally have no dirt and have a finer texture than potting soil. These mixes usually contain peat moss, perlite and/or vermiculite and coconut coir fiber.

Planting mix – These mixes are usually targeted for growing shrubs or trees and contain extended-release fertilizers. They frequently can contain peat moss, bark, and loamy soil.
Compost – Consists of decomposed organic materials.

So be sure to read the contents of the packaged soil you’re intending to purchase to make sure it contains what you are expecting it to contain.

For more gardening information go to cecolusa.ucanr.edu ■