How to Level a Bumpy Lawn

A bumpy lawn is more than just an eyesore. It makes mowing a frustrating experience, scalping high spots while leaving long grass in the dips. It creates trip hazards, ruins the appearance of stripes, and can even affect drainage. The good news is that leveling a lawn is a straightforward DIY job once you understand the techniques involved.

The approach you take depends entirely on how severe the bumps and hollows are. Minor undulations can be corrected with topdressing alone. Deeper problems need a more hands-on approach involving lifting and relaying turf. Either way, the result is a smooth, even surface that transforms the look of your garden.

What Causes an Uneven Lawn?

Understanding why your lawn became bumpy helps you prevent the problem returning. There are several common causes.

Settling is natural in newer lawns. Soil consolidates over time, and areas with different densities settle at different rates. This is particularly common where trenches were dug for utilities or where ground was disturbed during construction.

Frost heave pushes soil upward during winter freezes, then leaves it displaced when the ground thaws. This creates random bumps that worsen each year in areas with heavy clay soil.

Animal activity contributes significantly. Moles create obvious damage, but even worm casts can build up into lumps if not brushed away regularly. Birds, foxes, and badgers digging for lawn grubs can leave the surface churned up.

Buried debris often causes localised bumps. Stones, roots, old building materials, or even decomposing tree stumps beneath the surface create uneven settling above them.

Poor installation is a factor in many lawns. If the soil was not properly prepared and firmed before turfing or seeding, bumps are inevitable as the ground consolidates unevenly.

Leveling Minor Dips with Topdressing

For shallow depressions less than 20mm deep, topdressing is the solution. This involves spreading a thin layer of material over the lawn surface and working it into the grass, gradually building up low spots over multiple applications.

Choosing Your Topdressing Mix

The ideal topdressing for leveling is a mix of around 70% sharp sand and 30% topsoil or loam. This combination is heavy enough to settle into depressions but free-draining enough not to cause waterlogging problems.

Avoid using pure topsoil which can smother grass and create drainage issues. Similarly, pure sand works but may need fertiliser added since it contains no nutrients. Pre-mixed lawn topdressing from garden centres works well and saves the hassle of mixing your own.

How to Apply Topdressing

Mow the lawn short before topdressing so the material can reach the soil surface. Scarifying first removes thatch that would otherwise prevent the topdressing settling properly.

Spread the topdressing at around 2-4kg per square metre, focusing on low spots while avoiding high areas entirely. Use a shovel or bucket to distribute the material, then work it into the grass using a stiff brush, the back of a rake, or a proper lawn lute if you have one.

The key rule is never to apply more than 10mm depth in a single application. Any deeper and you risk smothering the grass beneath. The grass blades should still be visible poking through the topdressing when you finish.

Water lightly after application to help the material settle, then allow the grass to grow through before considering another application. Severely uneven lawns may need three or four applications over a couple of seasons to achieve a level surface.

Fixing Deeper Hollows

For depressions deeper than 20mm, or for raised bumps that cannot be solved with topdressing alone, you need to lift the turf and adjust the soil level beneath.

The Cut and Lift Method

Using a sharp spade or half-moon edger, cut a cross or H shape through the centre of the hollow, extending beyond its edges. Carefully peel back the turf sections, rolling them gently to avoid cracking.

For hollows, add topsoil to the exposed area, firming it down with your feet or a tamper. Build up slightly higher than the surrounding level since the soil will settle. For bumps, remove excess soil until the base is level with surrounding ground.

Relay the turf sections, pressing them firmly into contact with the soil beneath. The cuts will quickly heal and become invisible within a few weeks during the growing season.

When to Level Your Lawn

Timing matters for successful leveling. Spring and autumn are the ideal seasons when grass is actively growing but not stressed by heat or cold.

Avoid leveling in summer when dry conditions make turf vulnerable to damage and slow recovery. Winter work is possible but lifted turf is more likely to die from frost or waterlogging before it re-establishes.

For topdressing, early autumn is arguably the best time since it coincides with other autumn lawn care tasks like aeration and overseeding. You can aerate, topdress, and overseed in one session for maximum efficiency.

After Leveling Care

Once leveling work is complete, your lawn needs some attention to recover fully.

Keep foot traffic to a minimum while grass re-establishes, particularly over lifted turf sections. The roots need time to anchor back into the soil beneath.

Overseed thin areas to restore full coverage. Topdressing and turf lifting both create opportunities for grass seed to establish, so take advantage of the disturbed soil.

Feed with a balanced fertiliser to support recovery. Pre-seed feed is ideal if you are overseeding at the same time since it provides phosphorus for root development without the weedkiller found in standard lawn feeds.

Water regularly if conditions are dry, particularly over lifted sections where roots have been disturbed. New topdressing also dries out quickly until grass grows through to shade the surface.

Preventing Future Bumps

Once you have achieved a level lawn, a few simple practices help maintain it.

Brush worm casts away when they appear rather than mowing over them. This prevents them being compressed into permanent bumps. A stiff brush on a dry day scatters them easily.

Address mole and pest activity promptly before damage accumulates. The lawn grubs that attract digging animals can be controlled with nematode treatments.

Roll your lawn in spring when soil is moist but not waterlogged. A light roller firms the surface without compacting soil excessively. This is particularly helpful after winter frost heave.

Consider annual light topdressing as maintenance rather than just correction. Professional groundskeepers topdress sports pitches every year to maintain perfect levels, and the same approach works for domestic lawns.

For more lawn improvement techniques, browse our lawn care guides collection.