How do I overseed a patchy lawn?

Overseeding fails almost entirely for two reasons: the seed never reached soil, or it dried out during germination.

What you'll need

• Grass seed matched to the lawn's use
• A rake or scarifier
• Topdressing and a watering can or sprinkler

Step by step

1. Choose the right time.Early autumn is ideal — warm soil, reliable moisture and less competition from weeds. Mid-spring is the second choice. Summer sowing rarely succeeds.
2. Mow short first.Cut lower than usual so the new seedlings get light and are not shaded out by existing grass.
3. Scarify or rake hard.Remove thatch and moss and expose soil. Seed sitting on thatch cannot root and will not germinate — this is the step that decides success.
4. Match the seed to the situation.Hardwearing ryegrass mixes for family lawns, fine fescue mixes for ornamental lawns, and shade-tolerant mixtures under trees. Using an ornamental mix on a football lawn wastes money.
5. Sow at the recommended rate.Usually around 25 to 35g per square metre for overseeding. Too thick and the seedlings compete with each other and damp off.
6. Sow half in each direction.As with feeding, it evens out the coverage and avoids visibly thin lines.
7. Cover with a light topdressing.A thin layer of sieved topsoil or lawn dressing, brushed in. It holds moisture around the seed and protects it from birds.
8. Firm it gently.Light rolling or walking over it evenly. Seed needs contact with soil to germinate.
9. Keep it consistently moist.The single biggest factor. Light watering daily for two to three weeks — seed that dries out once during germination is dead, not dormant.
10. Keep off it.No traffic for several weeks, and mow only when the new grass reaches about 6cm, with a sharp high cut.
11. Do not feed immediately.Wait until the new grass is established. Fertiliser on germinating seed scorches it.

Tips

• Seed must touch soil. Scattering onto thatch or uncut grass achieves nothing.
• Early autumn is the best window — warm soil and reliable rain.
• Seed that dries out once during germination is dead. Consistency matters more than volume.

Common mistakes

• Sowing onto an unprepared lawn — Seed sitting on thatch and existing grass never reaches soil, so it does not root. Scarifying to expose soil is what makes overseeding work.
• Letting the seedbed dry out during germination — Germinating seed has no root reserve. A single dry day at the wrong point kills it, and it will not recover when watering resumes.

If it doesn't work

Questions people ask