One call we get a lot of in the Spring is “My lawn is really bumpy and uneven. Can you fix it?” Homeowners ask us if we will roll their lawn for them. On the heavy clay soil we have in the GTA, nothing short of a steamroller can exert enough pressure to flatten a lawn by force. And if you did manage it, the soil would be so compact it would choke your grass to death anyway.
If part of the lawn sinks and creates a depression the first thing to do is determine why. Removing the cause before correcting the effect is crucial. For any depression an inch or more deep, repair should involve removing the sod, correcting the cause of the sinking, and then back filling with new soil with enough extra to allow for settling. The removed sod can be put back in place if it is still in good shape, or replaced with new sod or seed. A shallow depression in the lawn – less than an inch deep – can be corrected gradually by sprinkling top dressing over it. Compost based mixes are good for this.
Bumps and rises also need to be diagnosed before correction. If caused by an object, it will need to be removed. If a bump is from burrowing animals they will have to be removed before the area can be smoothed. It may be possible to flatten smaller bumps by stepping on them.
Spring is the best AND worst time for people worried about lumpy lawn. The ground is soft and grass grows quickly to cover any repairs, but snowmelt-saturated soil plus traffic on your lawn add up to new bumps. You can read more in our April checklist. There are tips to avoiding creating ruts when you mow the lawn in our lawn cutting tips section as well.