Low spots in a lawn (depressions deeper than two inches or wider than three feet) present several challenges. These uneven areas create a tripping hazard and interfere with routine lawn maintenance. Mowing across them can result in “scalping,” where the blade cuts the grass too short in high spots. These depressions also collect water, leading to poor drainage and fostering disease or moss growth. Addressing large low spots requires a deliberate, multi-step approach that differs from simple topdressing.
Assessing the Depression and Selecting the Right Fill Mix
Before adding any material, accurately assess the depth of the depression. Placing a long, straight board or string line across the low area allows for precise measurement. This measurement dictates the repair strategy, as areas deeper than two inches usually require temporary turf removal to prevent smothering the existing grass.
Selecting the fill material is important for long-term stability and turf health. Pure topsoil is avoided because its high organic matter content decomposes, causing the area to settle again. Pure sand lacks the nutrients required for healthy grass growth. The ideal solution is a leveling mix, typically 70% fine sand, 20% high-quality topsoil, and 10% compost. This mix provides structural integrity, good drainage, and necessary nutrients.
The Process for Leveling Large Areas
For depressions deeper than two inches, begin by removing the existing turf. Use a flat-bladed shovel or sod cutter to slice the grass around the perimeter, rolling the sod back for later replacement. If the low spot is shallower (less than one inch deep), mowing the grass as short as possible allows the fill material to penetrate.
The leveling mix must be applied in shallow lifts to avoid suffocating established grass roots. Spread the material across the exposed soil or short-cut turf in increments no greater than one inch. This thin application ensures grass blades remain exposed, allowing them to continue photosynthesizing and grow through the new layer.
Once the mix is distributed, use a leveling rake, drag mat, or the back of a landscaping rake to work the material back and forth. This settles the mix into the low area, ensuring the surface is flat and blended with the surrounding grade. Slightly overfill the area initially to account for settling after the first watering.
Repeat adding thin layers of mix and leveling until the spot is even with the surrounding lawn. If the sod was lifted, roll the original turf back into place immediately after the final layer is applied. If the grass struggled to grow through, lightly overseed the repaired area with a matching grass type. Apply starter fertilizer to encourage rapid root establishment.
Watering and Post-Repair Maintenance
Immediate watering is required to integrate the new leveling material with the existing soil. For the first two to three days, water the repaired area lightly but frequently (multiple times per day). This helps the sandy mix settle fully into the turf canopy, exposing the grass blades and preventing the material from drying out and hardening.
Once the material has settled and grass blades are visible, transition to a deeper, less frequent watering schedule to encourage deep root growth. Monitor the repaired area for several weeks, as minor settling is common, especially in deeper fills. Small depressions can be addressed with a light follow-up application of the leveling mix and a quick brush with a rake. Do not resume regular mowing until the new or recovering grass reaches a height of at least three inches.