Lawn leveling is the process of smoothing out the surface of a yard by filling in depressions and bumps. Homeowners often undertake this project to achieve a more uniform aesthetic, make mowing easier, and reduce tripping hazards across the turf. While sand is often cited as a simple solution for filling low spots, using it incorrectly, especially as a standalone material, can be detrimental to the health of your turf.
The Problems with Using Pure Sand
Using 100% pure sand, particularly common types like play sand or masonry sand, can severely damage the existing lawn structure. Sand particles are relatively large and lack the organic matter necessary to sustain healthy grass growth. Applying pure sand directly on turf essentially starves the grass roots by withholding the nutrients and biological activity found in native soil.
A significant drawback involves the creation of distinct soil layers, which can impede proper drainage. When fine sand is applied over a native soil high in clay, the contrasting particle sizes can bind together, sometimes creating a dense, nearly concrete-like layer that repels water. This structural incompatibility hinders the vertical movement of water, potentially leading to a perched water table where the grass roots sit in saturated conditions above the sand layer.
Furthermore, many common sands, such as those used in construction, have angular grains that compact very tightly when wet, severely restricting the movement of air and water through the root zone. Healthy grass requires oxygen exchange to the roots, and a compacted layer of pure sand can effectively suffocate the turf. Pure sand also holds very little moisture, meaning the grass may suffer from drought stress during dry periods, requiring excessive irrigation.
Defining the Ideal Leveling Mixture
The recommended technique for correcting an uneven lawn is known as topdressing, which involves applying a nutrient-rich mixture rather than pure sand. An effective topdressing blend combines materials that promote both structural stability and biological health for the turf. A widely accepted ratio for this mixture is approximately 40% screened sand, 40% topsoil, and 20% organic matter, such as compost.
Each component serves a specific function within the blend to support the lawn. The screened sand provides the coarse, structural element that facilitates easy spreading and helps maintain good drainage within the layer. It is important to use washed, coarse sand, often referred to as horticultural sand, which has rounded particles that resist compaction better than fine sands.
The topsoil provides the necessary bulk and structure to fill the depressions, closely matching the texture of the existing lawn base. The inclusion of compost or another organic material introduces beneficial microorganisms and retains moisture and nutrients for the grass roots. This balanced approach avoids the nutrient deficiency and compaction issues associated with using sand alone.
Step-by-Step Guide to Application
Successful application begins with thorough preparation of the lawn surface to ensure the leveling mixture makes good contact with the soil. First, mow the grass at the lowest height possible without scalping, and then remove the clippings to expose the uneven areas. A light dethatching or aeration can also be beneficial, as it breaks up any dense organic matter layer that might prevent the mix from settling properly.
Once the materials are prepared, the mixture should be spread over the low areas using a shovel. It is crucial to apply the topdressing in thin, manageable layers to prevent suffocating the grass blades beneath a dense cap. The thickness of a single application should not exceed a half-inch, as the grass needs sufficient sunlight to push new growth through the material.
After spreading, use a leveling rake, a long leveling lute, or the back of a push broom to work the mixture down into the turf canopy. This action ensures the material settles around the base of the grass stems and into the low spots. For deeper depressions that require more than a half-inch of material, apply multiple thin layers, allowing the grass to recover between each application. Finally, water the area lightly to help settle the mixture and eliminate any air pockets, then resume a normal watering and feeding schedule to encourage the grass to grow through the new layer.