Lawns with lumps, ruts and low spots aren't only unpleasant to look at, they're also a safety hazard. Uneven ground underfoot is treacherous for walking, mowing and playing.
Many situations cause lawns to become uneven – some are preventable, others are not. The good news is that you can easily fix these problem areas in lawns. Learn common causes of lumpy lawns and how to make them smooth again.
Common Causes of Uneven Lawns
Mowing: If you follow the same pattern every time you mow, eventually you'll compact the soil beneath the mower wheels, creating ruts.
Wet soil: When soil is wet and mushy, add a heavy or rolling object – such as children on bikes, a wheelbarrow or a lawnmower – and you get ruts. This is one reason it's vital to avoid mowing when soil is wet. You might get away with it in well-drained areas, but in low spots where water gathers, you risk digging permanent ruts.
Heavy equipment: Maybe you had trees pruned or mulch delivered. The wheels alone wreak havoc with a lawn, forming ruts. If the equipment extends hydraulic platforms for stability, you'll also wind up with compacted soil that forms low spots.
Critters, pets and kids: When holes appear in a lawn and there's loose soil scattered around the hole, the culprit could be local critters, the family dog or children.
Tree stumps: Having a tree removed and the stump ground creates a low spot in the lawn. Any remaining underground wood eventually rots. At that point, the ground can suddenly collapse, creating a sinkhole-like depression.
Buried debris: When a hole appears in a lawn and there's no loose soil as evidence of digging, the most likely cause is soil subsidence. Buried trash that finally rots or decomposed tree roots can cause soil collapse.
Tips for Lawn Repair
The best time to repair ruts and holes in the lawn is when grass is growing most strongly. That means late spring (before the onset of hot weather) for warm-season grasses and early fall for cool-season grasses. For small areas, you can also tackle cool-season grass repair in mid- to late spring.
To fill in lawn ruts and holes, blend planting soil with sand and/or compost. Usually blending equal parts of each material forms a mix that allows grass to root effectively through the mix into existing soil. Check with your local extension agent or garden center for specific soil recommendations for your area.
If grass is still present in the rut, pry up the grass with a digging fork. If ruts are shallow, lifting the turf so it's 1-2 inches above the surrounding grade may be sufficient. Give it time to see if it settles evenly with surrounding turf. Otherwise, treat it as a low spot (see below).
For ruts deeper than 4 inches, use an edger and slice the grass in the center of the rut, then lift it and fold it up and back so it's resting on surrounding lawn. Loosen soil in the rut, adding more as needed to bring it 1-2 inches above the surrounding grade. Flip the turf back into place, water and wait for it to settle. Take care not to scalp this higher section of lawn when you mow.
If there's no grass present in the rut, loosen soil before adding more soil and seeding. Stick a digging fork into soil beside the rut at a 45-degree angle so the fork's tines are beneath the rut. Gently lever soil up by pushing down on the handle. Fill the rut with your soil mix, sow grass seed, and water.
When you're dealing with a low spot more than an inch lower than surrounding grass, lift any sod that's still present. Fill in the hole with soil, mounding it about 1 inch higher than the surrounding grade. Replace the grass, pat it lightly into place, and water. The grass should eventually settle into place. If there's no sod present, sow grass seed on open soil.
For large holes deeper than 24 inches, if turf is still present, remove it and set it aside to replant later. Fill the hole with broken bricks or large stones and cover with soil, bring the soil level to 1 to 2 inches above the surrounding grade. Set saved sod into place and sow additional grass seed as needed.