Smoothing Out a Bumpy Yard

We need to grade and smooth our lawn in the front of our property. It's extremely rough, and I don't like the way my teeth rattle while I'm mowing.

Older, established lawns like ours become rough and uneven over time, because the turfgrass compacts and thins. Freezing and thawing of the ground from season to season lifts up or "heaves" the soil, also making the surface bumpy. Animals digging through the lawn can also cause problems.

Gradual Repair

According to turf specialist Dave Minner, emeritus horticulture professor at Iowa State University, the re-establishment of a healthy, thick grass will help alleviate this problem. But if the thought of ripping up the yard and planting a new lawn sounds daunting, you can build it up gradually.

Fall or early spring is a good time to do this, because you'll want to start by giving the grass a butch cut with the mower. Ideally, the ground should be damp but not overly wet. If it is very dry, water well a day or two before you get to work.

1. The first step is to aerate the lawn. You can rent different types of aerators from hardware stores or home centers.
2. Allow the cores unearthed from the aerating to dry. Then use a drag implement that can be hooked up behind a lawn tractor to drag the plugs around and pull material from high spots to low spots in the lawn. (You can make your own drag with a piece of chain link fence and a couple of 2x4s.)
3. Once that's done, fertilize the lawn.

If That Doesn't Cut It

In some cases, a few rounds of aerating, dragging, fertilizing, and allowing the grass to grow will take care of the problem. If not, it may be time to consider top dressing: applying a thin layer of soil on top of the grass. You may only need to do this in a few areas where bumps and divots are especially bad.

"You could go out and top dress with compost, with sand and soil, with sand and compost, any of that combination, and you just basically keep filling it," Minner said. "Don't bury the grass completely; about a half-inch is about the most you'd want to put on at a single time and the grass will grow right up through it."

Make sure to choose top dressing that matches your yard's soil type, and examine it to ensure it doesn't contain rocks or weed seeds. It must be fairly dry in order to be uniformly spread. Professionals have specialty equipment for top dressing golf courses and other turf, but homeowners can use a drop spreader or even shovels.

You may need to top dress multiple times over the course of a few months. Overseeding may be needed in low-lying areas.

One thing you do not want to do is try to flatten the yard with a heavy roller. It will take care of some of the roughness, but it also damages the turf by compacting the soil, which is what you're trying to avoid.