How to Fix a Patchy Lawn

DIY Guide

Repair bare and thin patches in your lawn for a thick, even finish all season.

Quick Answer

Fix a patchy lawn by raking out dead grass, loosening the soil, applying pre-seeded lawn repair mix or fresh seed, and keeping it moist until established. Most patches show visible improvement within 2–3 weeks, depending on soil temperature and moisture levels.

Before

After

Difficulty

Beginner

Time

2–3 Hours

Cost

£15–£35

Tools Needed

Garden rake
Hand fork or border fork
Watering can or garden hose with rose attachment
Stiff-bristled brush or lawn brush
Knee pad or kneeling mat
Measuring tape

Materials

Lawn repair seed mix
Pre-seed lawn fertiliser
Topsoil or fine horticultural compost
Horticultural sharp sand (for compacted or clay areas)
Lawn edging pins or pegs (to protect seeded areas from foot traffic)
Garden netting or seed protection mat

How To

Step-by-Step Guide

BEFORE

AFTER

Identify and Diagnose Each Patch

Before reaching for seed, work out why the patch is bare. Common causes include compacted soil, shade, dog urine, moss die-off after treatment, heavy foot traffic, or a fungal disease. Press a trowel into the patch — if the soil is rock-hard or waterlogged, you need to address the underlying problem first, otherwise new seed will fail in the same spot. Check our Garden Guide for a broader overview of lawn health and seasonal care.

Prepare the Patch Surface

Scratch out all dead grass, thatch, and debris using a garden rake or hand fork, working the soil surface to a depth of around 25–50 mm. Remove any large stones, roots, or compacted clods. If the soil is very dense or poorly draining, work in a thin layer of horticultural sharp sand to open up the structure. Firm the area lightly by tamping with the back of your rake — you want good contact between seed and soil, not a loose fluffy surface.

Improve the Soil Before Seeding

Spread a thin layer of topsoil or fine horticultural compost across the prepared patch to a depth of around 10–15 mm, then rake level with the surrounding lawn. Apply a pre-seed lawn fertiliser at the rate recommended on the pack — this encourages rapid root development in young grass seedlings. Avoid applying a general high-nitrogen feed at this stage as it can promote leaf growth at the expense of rooting. If you are planning a larger overseeding project, see our guide on how to seed a bare lawn for full-area preparation steps.

Sow the Lawn Repair Seed

Use a lawn repair seed mix suited to your lawn type — shaded, hardwearing, or fine ornamental. Sow at the rate stated on the packaging, usually around 35–50 g per square metre for repairs. Scatter seed evenly by hand over the patch, then rake it lightly into the surface so roughly half the seed is in contact with the soil. Avoid heavy raking, which buries seed too deep. For patches larger than 1 square metre, sow in two passes at right angles to each other for even coverage.

Protect the Seeded Area

Lay garden netting or a seed protection mat over each patch and secure the edges with pegs. This deters birds and stops the seed from being disturbed by wind, rain, or foot traffic. Mark the area clearly if children or pets use the garden — even light foot traffic on newly germinated grass can kill seedlings. Keep the seeded patch consistently moist by watering lightly at least once a day in dry weather; the top 25 mm of soil should never dry out completely during germination.

Establish and Maintain the New Grass

Most grass seed germinates in 7–14 days at soil temperatures above 8°C — the Royal Horticultural Society notes that spring and early autumn are the optimal sowing windows for UK lawns. Once the new grass reaches around 50–60 mm, mow on the highest setting to avoid scalping young plants. Continue to avoid heavy use of the patch for at least four to six weeks after germination. Once the new grass has been mown two or three times and blends with the surrounding lawn, you can resume normal watering and feeding with a balanced lawn feeding programme.

Watch Out

Common Mistakes to Avoid

Should I use seed or turf to repair a patchy lawn?

Seed is cheaper and easier for small patches, but turf gives instant results and is better for patches larger than 1 square metre where you want a fast, uniform finish. Turf needs just as much ground preparation and watering commitment as seed in the first two weeks.

Why does my lawn keep getting patchy in the same spot?

Recurring patches usually indicate an underlying problem — compacted soil, poor drainage, tree root competition, shade, or repeated dog urine burn. Re-seeding without fixing the cause will produce the same result. Diagnose first, then repair.

How do I fix patches caused by dog urine?

Soak the affected area thoroughly with water immediately after urination to dilute the nitrogen concentration in the soil. Once the patch is brown and dead, rake out, top up with compost, and re-seed as normal. Watering the area daily for the first few weeks after seeding greatly improves establishment.

Can I fix a patchy lawn if it’s also full of moss or weeds?

Treat moss and weeds first — applying a moss killer or selective lawn weedkiller and waiting the recommended time before re-seeding. Seeding into an area with active moss or weed growth means the new grass will be outcompeted before it can establish. See our guide on how to scarify and aerate a lawn for clearing heavy moss before repair work.

Pro Tip

Mix a small amount of fine horticultural compost into the seed before broadcasting — it acts as a carrier that improves even distribution and helps retain moisture directly around each seed during the critical first week of germination. This is especially effective on sandy or free-draining soils where surface moisture disappears fastest.

Sources

RHS — Lawn repairs: reseeding and turfing — rhs.org.uk
Which? — How to repair a lawn — which.co.uk
RHS — Lawn problems: causes and solutions — rhs.org.uk

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