So many of our customers, both commercial and residential, ask the question, "What's the difference between dirt and topsoil?" Well, to be exact, there are differences between all types of dirt and topsoil, to complicate matters even more. But let's take a look further into what the differences are and what material would be best for any given project you might be doing, either for your yard, landscaping or gardening.
Where the differences lie between the different dirt and soils becomes apparent not only visually, but also by testing each soil to see how it is composed of physically and chemically.
There are various tests that homeowners can do to check the Ph of their soil, either by sending a sample in the mail to a laboratory, there a online services for this. You can also purchase your soil test kit at many local nurseries or garden shops. Another option is your local farmers supply store, which may also have a service for this type of soil testing. LaMotte, a Maryland based company, produces soil testing equipment, which you can purchase online. One-time soil testers are good for the individual homeowner, or for the avid gardener or farmer that needs to test soils year round, perhaps the whole kit with multiple uses would be best.
Visually "dirt" is categorized as either a select fill or a common fill dirt. Select fill is a virgin material that, more often than not, has been excavated directly from a sand quarry or job site. The select fill is considered clean of trash, debris, roots, etc. and is a good material for many projects, including back filling or raising the grade of an area. Although select fill is typically on the sandy side, there may also be trace silt, clay and gravel composed in the material. Common fill is typically a soil that has more debris in it and may have more clay or roots. Common fill may also come from various locations, such as from job sites, and may comprise of many types of soil types. Common fill is generally used where compaction, clay or other materials that may be present in the soil is not an issue.
There are many different grades of dirt, however, knowing the key differences referenced in the post above may help in deciding which one will be best for your project.
While dirt composition may be easier to figure out, topsoil on the other hand can vary vastly. Topsoil is found typically in the first 2-3 inches top layer of the earth. The various nutrients, organics and composition is what distinguishes the various topsoil from one another. When you buy bulk screened processed topsoil, it is material that has been taken from it's original location, and then screened (processed) to remove roots, excess gravel and debris generally comes from multiple sources and locations, however, the final product is close in organics and chemistry from day to day.
Depending on your location, your soil will vary greatly. Here in central Maryland, our topsoil tends to be on the sandy side, however, there are some areas that have a lot of clay, and that is where testing the soil is critical to find out what you have to work with. So, why is healthy topsoil so important? Plants generally concentrate their roots in and obtain most of their nutrients from this layer. The actual depth of the topsoil layer can be measured as the depth from the surface to the first densely packed soil layer known as subsoil. The "subsoil" is mentioned in this blog post as select fill.
The presence of organic materials in soil is what sets topsoil apart from subsoil and what makes it a vital component of productive agriculture or lush green lawn. The more organic substances, the better. You can reasonably judge the quality of organic substances in topsoil by observing color and texture. Topsoil with a granular structure and dark color is generally ideal for cultivation. If organic material is inadequate, it can be boosted with the addition of organic amendments like peat moss or compost, including LeafGro, available in the Crofton Retail yard in bulk.
Usually a combination of sand, clay and silt is the preferred topsoil mixture, as it provides an ideal water-holding capacity for growing plants. Sandy soils have trouble retaining water, and water tends to drain quickly. Clay soils are dense, and their small pores hold water for a long time. High levels of organic matter tend to improve soil tilth, structure, drainage and water-holding capacity. The texture of soil is indicative of its composition.
Good topsoil has a fine texture, contrasting with the coarser structure found in subsoil layers. You can evaluate topsoil structure by feeling the texture of soil in your hands. Coarse particles indicate the soil is sandy, while smooth particles are signs of clay soil. Crumbly texture is ideal for seed beds and gardens. Soil texture is a vital component of topsoil quality because it determines the soil's water-holding capacity and the ease of working the soil (tilth). Beware of hard soils, which may have too little organic content or too much clay.
No matter your type of topsoil, when in question, adding soil amendments, such as LeafGro organic leaf compost, helps boost the soils texture, nutrients and overall health of the soil and your vegetation and lawn will thank you.