If you have already taken a look at my advice on lawn pests here and ruled them out, we have more help at hand. Lawn specialist Matt J Adams, founder and lead gardener at The Relentless Gardener, take us through what else it could be and what you can do.
A lawn that’s looking thin, patchy or suddenly covered in bald spots can be frustrating -particularly when you’re not sure what’s gone wrong. If you’ve already ruled out pests such as leatherjackets and chafer grubs, there are plenty of other reasons why grass can start to struggle.
Heat and drought, shade, compacted soil, heavy foot traffic, poor drainage and mowing too short can all cause lawns to become thin or develop bare patches. The good news is that once you understand what’s causing the problem, it’s often possible to help the grass recover without completely starting again.
Before reaching for a treatment, it’s worth taking a closer look at the pattern of the damage and the condition of the grass. “If you’ve ruled out pests as the cause of lawn damage, look closely at what is happening rather than assuming the grass needs replacing,” says Matt. “The pattern of the damage, where it’s occurring and the condition of the soil can all give you useful clues about what your lawn needs.”
Here, Matt explains some of the most common reasons lawns develop bald or unhealthy- looking patches, how to identify the likely cause and what you can do to help your lawn recover.
Brown or straw-coloured grass? Think heat or drought
After a prolonged period of hot, dry weather, grass can turn brown without actually being dead. Grass can go dormant during prolonged dry weather and recover when temperatures fall and moisture returns. If your lawn has suffered during a hot summer, don’t immediately assume the grass needs replacing. Wait for cooler conditions and rainfall to see whether it starts producing fresh green growth.
During hot weather, avoid cutting the lawn too short. Longer grass helps shade the soil, reducing moisture loss, while deeper roots can make the lawn more resilient during dry spells. If you do need to mow, raise the mower height and only remove around a third of the grass height.
Bald patches in high-traffic areas? Check for compaction
If the worst areas are around pathways, patios, play areas or anywhere people regularly walk, compacted soil could be contributing to the problem. Walking on stressed or recovering grass can compact the soil, squeezing out the air pockets roots need for oxygen, water and nutrients. Compacted soil also makes it harder for new roots to grow.
Once conditions are cooler and the lawn is actively growing, aeration can help improve the movement of air, water and nutrients into the soil. However, avoid aerating during a heatwave when grass is already under stress.
Thin grass under trees or beside fences? It could be shade
Grass needs light to grow, so areas underneath trees, beside fences, walls or other structures can naturally struggle.
The answer isn’t necessarily more fertiliser. Choosing a grass seed mix suited to the conditions can make a significant difference. “Lawns in sunny positions benefit from grass seed mixes containing more ryegrass,
whereas shady lawns need more fescue seed,” says Matt. For shady areas, The Relentless Gardener Premium Shade Grass Seed is designed for. lower-light conditions and can be used to repair thin areas.
Patchy, mossy or constantly wet? Look at the soil
If a lawn is persistently damp, mossy or slow to recover, the problem may lie beneath the grass. Clay soils can hold water and create poor drainage, while compacted soil can make it harder for water and air to move through the root zone. A simple squeeze test can give you an indication of your soil type: sandy soil tends to flow through your hand, clay sticks together, while loam should feel light and easy to break apart. The Relentless Gardener 70/30 Sand/Soil Top Dressing can help improve drainage and soil structure, while also improving seed-to-soil contact when overseeding.
Lots of weeds? The grass may need strengthening
Weeds are often more noticeable when a lawn becomes thin because they have more space to establish. Rather than simply treating the weeds, look at why the grass has become weak. A dense, healthy lawn is better able to compete with weeds. “The best way to prevent weeds taking over is to grow a strong, healthy lawn in the first place,” says Matt. “A good feeding programme, combined with improving the soil, will help create stronger grass that can compete with weeds.”
How to repair a bald patch
Once you’ve identified the likely cause, repairing a bald patch is usually straightforward. “Start by raking out the dead grass and lightly disturbing the soil,” says Matt. “If the soil is particularly compacted, aerate the area before applying a light layer of topsoil. Then sow an appropriate grass seed, cover it with a little more topsoil and gently press or roll the area to improve seed-to-soil contact.” Mow the surrounding grass to around 45mm or more, giving new seed plenty of light and space to establish.
For shady areas, Premium Shade Grass Seed is designed for lower-light conditions, while a hard-wearing mix containing perennial ryegrass and fescues is better suited to lawns that experience regular foot traffic. Once you’ve sown the seed, keep the area moist while the new grass establishes. Newly seeded areas need consistent moisture, so don’t allow the surface to dry out.
Feed the lawn – not just the patch
It can be tempting to sprinkle fertiliser directly onto a bald patch, but the better approach is to think about the lawn as a whole.
“Once the new grass begins to establish, resist the temptation to feed just the patch,” says Matt. “Instead, feed the whole lawn when it’s next due, keeping everything on the same feeding programme for a healthier, more consistent lawn.”
If you’re repairing a lawn in autumn, choose an autumn-specific feed rather than a high-nitrogen spring or summer fertiliser. The aim is to support healthy roots and winter resilience rather than encourage lots of soft, leafy growth.
The Relentless Gardener Premium Autumn Lawn Feed is designed to support lawns through autumn and into winter.
Don’t try to fix everything at once
A lawn that looks tired after summer doesn’t necessarily need a complete renovation. Start by working out what has changed. Has it been particularly dry? Has the area had lots of foot traffic? Is the soil compacted? Does it receive enough sunlight? Is water sitting on the surface? Has the grass been cut too short? Or is the lawn simply thin and in need of new seed?
“Autumn is one of the most important times of year for lawn care, particularly if your grass has had a difficult summer,” says Matt. “The good news is that you don’t necessarily need to completely renovate the lawn. In most cases, a little well-timed attention can make a significant difference.”
The Relentless Gardeners’ lawn diagnosis checklist
- Brown but not bald? Give it time to recover from heat and drought.
- Bald from heavy use? Check for soil compaction and aerate when conditions are suitable.
- Bald under trees or beside fences? Consider shade-tolerant grass seed.
- Mossy or constantly wet? Investigate drainage and soil structure.
- Lots of weeds? Focus on building a stronger, denser lawn.
- Genuinely bare patches? Rake, prepare the soil, over seed and keep the area moist while new grass establishes.
A healthier lawn isn’t necessarily about throwing more treatments at it. Quite often, the best place to start is by understanding what your grass is trying to tell you.
For more information and advice about lawn care, visit www.relentlessgardener.co.uk.
Matt J Adams is the founder and lead gardener at The Relentless Gardener, a specialist in grass seed, lawn feed and plant nutrition products, on a mission to make gardening and lawn care easy and convenient for everyone in the UK.
Matt combines horticultural knowledge with hands-on experience to develop premium products tailored to the needs of UK gardens. Working alongside one of the UK's largest and most trusted lawn feed and fertiliser
manufacturers, he has helped create scientifically developed formulations and pioneered an innovative lawn size calculator that enables customers to buy the exact amount of product they need. Matt regularly shares practical, evidence-based advice on lawn care, soil health and plant nutrition, and is a trusted media commentator on seasonal gardening topics, helping gardeners achieve healthier, greener gardens with less waste.