How do I fix a patchy lawn?
Diagnosing bare patches, repairing them with seed or turf, and the aftercare that decides whether the repair takes.
- Difficulty
- beginner
- Time
- 2 hr
- Read
- 2 min
Short answer
Scarify out the dead material, loosen the soil, add a thin layer of topsoil, sow seed and keep it consistently damp for three weeks. The watering is the part that fails — new grass seed dies within a day of drying out.
Bare patches have causes: compaction, shade, pet urine, drought, or disease. Repairing the patch without addressing the cause means repeating the work next year, so the diagnosis is worth five minutes.
What you'll need
- Grass seed
- Topsoil or compost
- Rake
- Garden fork (optional)
- Watering can (optional)
Step by step
- Work out why the patch is bare before repairing it.Heavy footfall means compaction. Under a tree means shade and root competition. Round yellow patches with green edges usually mean dog urine.
- Rake out dead grass, moss and thatch from the patch.Be vigorous. Seed needs contact with soil, not a mat of dead material.
- Fork the area over if the soil is compacted.Push a fork in 10cm and rock it gently, every 10cm across the patch. Compacted soil is the most common underlying cause.
- Add a thin layer of topsoil or compost and level it.About 1-2cm, raked level with the surrounding lawn. It gives the seed something to root into.
- Sow seed at the rate on the packet, then rake it in lightly.Choose a mix suited to the site — shade mixes and hard-wearing mixes genuinely differ. Sowing too thickly causes disease.
- Firm gently and water thoroughly.Press with the back of a rake or tread lightly. Good seed-to-soil contact matters.
- Keep it consistently damp for three weeks.This is the step that determines success. A day of drying out kills germinating seed, and light daily watering beats occasional soaking.
- Keep off it and do not mow until it is 5-6cm tall.Then mow high with a sharp blade. Early mowing pulls new grass out by the roots.
Tips
- Sow in autumn or late spring when soil is warm and moist. Summer sowing needs constant watering and often fails.
- Netting or fleece over a patch keeps birds off the seed and holds moisture. It is worth doing.
- For dog urine patches, water the area heavily immediately after to dilute it. Prevention is easier than repair.
Common mistakes
- Sowing onto compacted, un-raked ground — Seed needs soil contact. Sown onto thatch or hard ground, most of it never germinates.
- Letting the patch dry out during germination — Germinating seed dies within a day without moisture, and the whole repair is wasted.
- Mowing too soon — New grass has shallow roots and a mower pulls it straight out. Wait until it is 5-6cm and cut high.
Questions people ask
When is the best time to sow grass seed?
Early autumn is ideal — warm soil, reliable moisture and less competition from weeds. Late spring is the second-best option. Midsummer is difficult because of watering demands.
How long does grass seed take to grow?
Usually seven to twenty-one days depending on temperature and species. It must stay consistently moist throughout, or it dies at germination.