If you have been researching starting a garden or improving your garden, you have probably seen the word “topsoil.” Topsoil found naturally in the native soil in your garden is different than the topsoil you find at your local nursery or home center. We will review the difference and when to use the kind found at your garden center. But first, let’s understand what is soil?
What is Soil?
Many call it dirt, we like to call it soil. There are several different types of soil found at your local nursery or home center garden center. Let’s review the most common types.
First let’s look at potting soil. Potting soil, also referred to as potting mix, is a growing media specifically formulated for plants grown in containers. Interestingly, though potting soil has “soil” in the name, it usually doesn’t contain actual soil. It is actually created using a combination of ingredients such as: composted wood, peat moss, compost, sand, and organic nutrients such as composted poultry manure, worm castings and even kelp meal. The potting soil you need will depend on where you are growing your plants – indoors or outdoors. Will it need to have ingredients to help with greater water retention or well-draining? These are a few factors to consider when choosing the perfect potting mix for your potted plants.
Garden soils are formulated to be mixed 50:50 with the native soil found in your garden or landscape for in-ground planting. It is not made for using in containers like the potting mix above. The particle size in a garden soil is slightly larger to help create pockets in the soil that allow greater penetration of water and air deeper into the ground. This helps develop a stronger root mass for a more lush, healthier plant. Garden soils can be formulated to be used to grow a wide variety of plants from flowers and vegetables to trees and shrubs.
There is also the existing soil in your garden or yard, which can be a unique combination of clay, sand, silt, and loam. In most cases, the soil composition in your area will be predominantly one or two of these soil types which can make in-ground gardening very challenging or very satisfying. Whether you have challenging clay soil in your garden or easy-to-work-with sandy-loam, adding organic matter to your native soil helps build life in the soil – to retain more moisture so you don’t have to water as often; provide plant-available nutrients that create a healthy, sustainable garden reducing the risk of pests and disease.
And then, there is topsoil. True topsoil is found in native soil. It is the top layer of soil, which can be 4 to 12 inches in depth. The texture and compilation of materials may vary. However, topsoils that are more loamy (than clay or sand based) are often best because they are rich in organic matter that holds not only moisture, but also an entire ecosystem of beneficial microbial life that contribute nutrients for healthy plant growth.
What is Topsoil Used for?
Topsoil purchased at a garden center can be an economical way to amend your garden bed and lawn. There are different types of topsoil, so be sure you pick the one best suited for your project. Good topsoil contains the necessary nutrients for your plants to survive. It can help protect plants and seedlings, as well as correct soil issues like improper pH levels (if the purchased topsoil contains certain ingredients that can help, like limestone). This type of topsoil is considered a blended topsoil and tends to be more like a garden soil. The two in many ways, could be considered one-and-the-same since they perform the same function when mixed with native soil.
Certain blended topsoil, for example, can help to improve soil drainage. Using a sandy-blend topsoil with organic matter mixed into the native soil will help provide better drainage, allowing water to penetrate deeper which contributes to stronger root development.
Blended topsoil, like garden soil, can be used for many in-ground applications, including:
- New builds (like new lawns, new garden beds, or replacing a previously paved area with plants)
- Areas affected by soil erosion
- Damaged and heavily used areas of lawns
Because of these benefits, you may find yourself needing to use less water, and reduced use of pesticides – giving you more time to focus on the other aspects of your garden, like planting, harvesting, seasonal swap-outs, and more.
The most common use for bagged topsoil is a top-dressing on damaged areas of the lawn or garden. It typically contains little nutrient value but are a great filler or top-dressing. It can fill in bare spots, low spots, or heavily trafficked areas that are beaten down. (Note that you will need to watch the soil structure, as the topsoil may change the pH level – if you notice any changes, a soil test can help determine next steps to take.)
Topsoil is typically several inches deep, so if your topsoil is thin or even nonexistent, it may be a good idea to consider applying topsoil or garden soil to your garden. Check the topsoil you choose to see what ingredients it contains, and look for specialty blends or garden soils if you need pH correction, better drainage, or more nutrients.