Why Your Lawn Is Patchy and How to Fix It

Common Causes of Patchy Lawns in the Chilterns

1. Shade

The most common cause in our area. Grass needs at least 4 hours of direct sun. Under trees, along north-facing walls and beside fences in gardens around Beaconsfield, Gerrards Cross and Great Missenden, grass thins and patches develop. The mature trees that make Chiltern gardens so attractive are also the main cause of shade-related lawn patches.

Fix: Prune trees to let in light, or overseed with a shade-tolerant fescue mix. See our lawn planning tool for seed recommendations. In heavily shaded areas, consider replacing the lawn with shade-tolerant ground cover.

2. Compaction

Heavy foot traffic, children playing and heavy mowing compact the soil. Grass roots cannot penetrate compacted soil, so the grass thins. This is particularly common on clay soils in Aylesbury, Bicester and Didcot, where the soil compacts easily when wet.

Fix: Aerate annually with a hollow-tine aerator. See our aeration guide.

3. Dog damage

Dog urine contains nitrogen that burns the grass, creating circular patches. Female dogs cause more damage because they squat rather than lift. This is a common problem in family gardens across Oxfordshire and Buckinghamshire.

Fix: Water the area immediately after the dog urinates to dilute the nitrogen. For existing patches, rake out the dead grass, add soil and overseed with a hard-wearing ryegrass mix.

4. Drought

In dry summers, grass goes dormant and patches appear. This is natural and the grass usually recovers when rain returns. However, on the free-draining chalk soils of the Chilterns around High Wycombe, Stokenchurch and Watlington, drought patches can become permanent if the dry spell is long enough.

Fix: Water deeply once a week during drought. See our dry summer lawn guide. Overseed drought-damaged areas in autumn with a drought-tolerant fescue mix.

5. Disease

Fungal diseases like red thread, fairy rings and snow mould cause patches. These are more common in wet conditions and on lawns that are over-fed with nitrogen. Lawns in the Thames Valley around Reading and Twyford can be particularly vulnerable to fungal diseases in wet autumns.

Fix: Improve drainage, reduce thatch, and apply a fungicide if needed. See RHS lawn disease guidance.

6. Pests

Leatherjackets (crane fly larvae) and chafer grubs eat grass roots, causing patches. Birds pecking at the soil for the grubs make it worse. This is an increasing problem across the Chilterns and Thames Valley.

Fix: Apply a biological nematode treatment in autumn. See RHS leatherjacket guidance.

7. Poor mowing

Cutting too short scalps the grass and weakens it. This is a common problem when homeowners cut the lawn themselves and set the mower too low, especially during the hot Chiltern summers when the grass is already stressed.

Fix: Never cut more than one third of the grass height in one mowing. Set the mower to 30 to 40mm for family lawns, higher in dry weather.

8. Poor feeding

Under-fed grass is weak and patchy. On chalky Chiltern soils, nutrients are easily leached out, so regular feeding is even more important than on heavier soils.

Fix: Apply a balanced fertiliser in spring and a low-nitrogen feed in autumn.

How to Repair Patches

1. Rake out the dead grass with a spring-tine rake
2. Loosen the soil surface with a garden fork
3. Add a thin layer of topsoil or compost
4. Sow seed at 30g per square metre
5. Rake in lightly and water
6. Keep moist for 3 weeks
7. Protect from birds with netting

Use Our Lawn Planning Tool

For a seed variety recommendation based on your lawn conditions, use our lawn planning tool. It recommends the right seed for your soil type, sun exposure and main problem.

Get Help with Your Patchy Lawn

If your lawn in Oxfordshire, Buckinghamshire, Berkshire or Bedfordshire is patchy and you want professional help, contact us on WhatsApp with a few photos.

Frequently Asked Questions

How do I know if my patches are caused by pests?

Lift a section of turf. If you see white grubs or grey-brown larvae in the soil, you have chafer grubs or leatherjackets. Birds pecking at the lawn is also a sign.

Can I repair patches in winter?

No. Grass seed will not germinate in cold soil. Wait until March or April when the soil warms up.

How long do patches take to fill in?

With the right seed and regular watering, patches fill in within 3 to 6 weeks in spring or autumn.

Further Reading

• Why is my lawn full of moss?
• How to repair a lawn after dogs and children
• Aeration, overseeding and top dressing explained
• Keeping a lawn green in dry summers

Sources and citations

This article draws on the following sources. Specific claims are cited inline where relevant.

1. CGM field records (2026-07. Site observations from gardens across Oxfordshire, Buckinghamshire, Berkshire and Bedfordshire.
2. Royal Horticultural Society (2024). RHS Gardening Advice and Plant Finder. Available at rhs.org.uk.
3. Met Office (2024). Regional climate averages, South East England. Available at metoffice.gov.uk.
4. British Geological Survey (2024). Soil parent material data for the Chilterns and Thames Valley. Available at bgs.ac.uk.