How to Level a Bumpy Lawn

A bumpy lawn is annoying to mow and can be a trip hazard. The good news is that most lawns can be levelled without ripping everything up and starting again.

What causes a bumpy lawn?

• Settling: Soil settles unevenly over time, especially after building work or where services have been laid.
• Worm casts: Earthworms bring soil to the surface, creating small bumps.
• Frost heave: Freezing and thawing can push soil upwards.
• Poor preparation: If the ground was not levelled properly before turfing or seeding.
• Tree roots: Roots growing near the surface push the lawn up.
• Animal activity: Moles, foxes and badgers can create bumps and hollows.

When to level a lawn

The best time is spring (March to May) or early autumn (September to October) when the grass is growing actively. Avoid summer when the lawn may be dry and stressed, and winter when growth has stopped.

Method 1: Top-dressing for minor bumps

For shallow dips and minor unevenness, top-dressing is the simplest solution. You spread a thin layer of sandy loam or a lawn top-dressing mix over the surface and work it into the grass.

1. Mow the lawn short (but not scalped) so you can see the levels clearly.
2. Spread top-dressing over the low areas, no more than 10-15mm deep at a time.
3. Work it into the grass with the back of a rake or a stiff brush.
4. The grass should still be visible – do not bury it completely.
5. Water lightly if the weather is dry.
6. Repeat after 4-6 weeks if needed.

For deeper hollows, you may need to repeat this process several times over a season rather than filling in one go.

Method 2: Lifting turf for bigger bumps and hollows

If you have significant bumps or hollows (more than 25mm), top-dressing alone will not work. You need to lift the turf, adjust the soil underneath, and relay it.

1. Cut an H-shape or cross in the turf over the problem area with a half-moon edger.
2. Peel back the turf flaps carefully, keeping them attached at the edges.
3. For a bump: remove soil until the area is level with the surrounding lawn.
4. For a hollow: add soil and firm it down until level.
5. Fold the turf back into place and firm it down.
6. Fill any gaps with fine soil and water well.

Dealing with tree roots

If tree roots are causing bumps, you have limited options. Cutting large roots can damage or kill the tree. In most cases, you either accept the uneven surface or consider removing the tree. For minor surface roots, adding a thin layer of soil can help, but the roots will eventually push through again.

Preventing future bumps

• Brush off worm casts: When dry, brush them flat before mowing.
• Avoid heavy traffic: Repeated walking on the same path compacts and wears the lawn unevenly.
• Deal with moles promptly: The longer you leave mole hills, the more the soil settles unevenly.
• Roll in spring: A light roll with a half-filled roller can help settle minor unevenness after winter.