San Diego Topsoil, Compost and Mulch

The foundation for any successful garden is the proper mixture of topsoil and compost that your seeds are planted in. A proper garden mix will contain measures of topsoil and compost with a layer of mulch added on top to aid with water retention.

Topsoil, sometimes referred to as dirt is native soil that resides above lower layers of bedrock and contains a mixture of native substances such as sand, clay, rock and naturally composted organic matter. Topsoil quality varies tremendously by region. If you’re not sure of the quality or suitability of your native topsoil for use in a growing mix take a handful to your local nursery for evaluation.

Compost is organic matter that is naturally broken down into a dark brown, soft, soil-like material that is full of nutrients. Along with delivering nutrients to your plants compost helps aerate dense soils and also aids in water distribution and retention.

Mulch is ground-up organic matter that has not broken down to compost. Commonly used mulches are grass clippings, straw, ornamental plant clippings and any other material that provides your garden planting mix with a nice cover that helps retain water and discourages certain crawling and slithering pests. Some gardeners have been known to use newspaper for mulch.

Opinions vary but a reasonable consensus calls for a mixture of at least 30% compost and 70% topsoil. The mixture will depend heavily on the quality of the topsoil used. Many native soils around the San Diego County coastal region are heavily laden with sandy-clay loam soils that require an abundance of compost and organic matter to provide necessary nutrients and water retention qualities.
Many gardeners in this region use at least 30% compost and even more to obtain desirable growing characteristics. Don’t be afraid to experiment with growing mixtures.

Topsoil can be native (from your yard) or imported depending on what you have available. Many gardeners in San Diego choose to import topsoil as many native topsoils leave much to be desired.

Topsoil, compost, mulch and ready-made growing mixes can be obtained at many local nurseries and garden supply stores such as:

City Farmers Nursery
Armstrong Garden Centers
Walter Andersen’s Nursery
Miramar Landfill

Or ask us for assistance is locating and delivering the soil products you need.