The ideal rolling green lawn is a completely flat, trim field, but it takes ongoing attention to keep it this way. If you don’t regularly top dress and level your lawn, you’ll notice the lumps and divots that can develop over time from many different causes. Even a healthy lawn will have its share of bumps now and then.
Lumpy lawns aren’t necessarily bad, but sometimes they are a sign the soil needs to be adjusted in one way or another. When the bumpiness gets out of hand, it can make mowing difficult or inefficient, dulling mower blades and resulting in unevenly cut grass that can stress out the lawn.
A bumpy lawn can also be a tripping or ankle-sprain hazard. Those same divots can pool water and damage grass roots, while unevenly cut grass can create a habitat for pests.
What Is Causing Bumps In My Lawn?
With time, soil shifts naturally from a number of causes. Some are normal and unavoidable, and others are signs of problems that should be addressed. When it comes to uneven lawns, knowing why the ground is bumpy in the first place will let you know which steps to take to level it out.
- Poor drainage – When water pools on the surface of compacted or clay-heavy soil, it creates a lot of mud, leading to shifting and an uneven surface texture. Wet topsoil can also damage grass roots, creating bare spots in the lawn which can easily lose or shift soil.
- Ground exposure – Bare spots, thin grass, or ripped turf expose the surface of the topsoil, which can then be lost or shifted by wind and rain.
- Irrigation trenches – Some yards have built-in trenches, either underground pipes or swales to redirect water so it doesn’t pool in the yard. When irrigation pipes from drainage or sprinkler systems are removed, they can leave uneven impressions in the ground’s surface.
- Heavy traffic – One easy way a lawn can develop a bumpy surface is from active use. The lawn is there to be enjoyed, but foot traffic from people and dogs can compact soil unevenly.
- Pests – If your lawn is home to pests or rodents, like ants or gophers, their underground tunnels displace dirt and create divots and holes that result in bumpy ground.
- Rocks in the yard – Rocks and large gravel in your yard can contribute to an uneven level. Small stones block grass growth, which can result in bare spots in the lawn, thin growth, or small spots of compaction.
- The grass – The grass itself can affect the surface level of the yard. A dense turf holds its shape better because lots of interlocking roots and a healthy thatch will provide structure to hold the soil in place, while a thick grass cover will protect the soil from shifting in wind and rain. Creeping warm season grasses like Bermuda and centipede keep the ground flatter than clumping grasses like rye and fescue.
- Natural soil heave – Soil can shift naturally over a while without major disturbance. In places where the ground freezes, the expansion and contraction as soil moisture turns from ice to water and back heaves the soil slightly each year. Decomposers in the soil, like worms and other bugs, change the texture as they move the dirt around and create new soil.
How Do You Get Rid Of Bumpy Grass?
The cause of the bumpiness will guide you towards your remedy. If the uneven ground is a pest or rock issue, removing those is the first step. Hard ground (whether from clay, which can get very hard, or compacted soil) that is leading to bare spots or pooling of water should be aerated and amended with sand and compost to promote drainage and a porous structure.
For divots, thin or bare grass, and ground that has shifted naturally over time, the soil should be top dressed with a 50/50 soil and sand mix (be sure to use topsoil that doesn’t contain wood products for smooth coverage). This ensures good drainage while creating new structure and adding bulk to the lawn. The soil and sand mix should be applied a few shovel-fulls at a time and spread out with a leveling rake or the flat edge of a garden rake.
Even in the bumpiest yards, you shouldn’t be laying down inches of soil at a time. This can bury and suffocate too much grass and end up harming the lawn. Some areas will be deeper than others, but as you pass the leveling rake around, it will clear off the higher spots, fill in the deep spots, and show you the topography of the lawn.
Those recently-filled in areas should be overseeded to promote new growth and hold the soil in place. Aerating and applying fertilizer a couple of weeks before doing a leveling will encourage your lawn to grow and be prepared to extend into the newly filled-in areas.
How Do You Keep The Yard Level?
Topdressing lightly with compost, topsoil, and sand when you aerate the lawn in early spring or early fall will help build the soil, which will contribute to a healthier growing environment for the grass. When the ground retains moisture, is well-aerated, and has plenty of organic material, your grass will build dense root and thatch systems that hold the soil firmly in place, decreasing the amount of shifting of the soil.
Should I Use A Roller?
A roller likely isn’t going to be useful for your yard leveling project. Rollers are best for sports fields that are regularly torn up and need to be flattened out for new grass seed. They don’t work well on grass that’s already grown, and a roller can lead to compaction, not really addressing any of the underlying reasons for bumpiness across the lawn.