Find exactly how much grass seed you need to overseed thin, patchy, or worn UK lawns. Adjust by lawn condition — light green-up to full bare-patch repair.
Standard UK overseeding rates range from 15g to 50g per m² depending on how worn or patchy your lawn is. Select your lawn condition below for the correct rate.
For thin, patchy and worn UK lawns — all grass types
Step 1: Select your lawn condition
Step 2: Enter your lawn size
Bags Required (approximate)
The scarify-first method is the most effective approach for overseeding a worn or patchy lawn in the UK.
Rake out thatch and moss vigorously using a lawn scarifier or hand rake. This opens up the soil surface and allows seed-to-soil contact — the single most important factor for germination success.
Mow the existing lawn to around 25mm before overseeding. Remove all grass clippings so they don't smother the new seed. A clear, firm surface is your goal.
Divide your calculated seed weight in two equal halves. Sow one half walking up and down the lawn, then sow the second half walking left to right. This cross-hatching technique prevents strips and patchiness.
Optionally apply a light top dressing of sharp sand or sandy loam to press seed into the surface. Water with a fine mist immediately after sowing and keep soil consistently moist for 14–21 days until seedlings establish.
Soil temperature and moisture are the two critical factors. Grass seed requires soil temperatures of at least 7–8°C to germinate in the UK.
Not every lawn needs the same seed rate. Match your overseeding rate to your lawn's current condition for the most cost-effective result.
The lawn is mostly green but looking sparse. A light overseed improves density without disturbing existing grass.
Visible bare patches, worn traffic lines, or post-scarification. This is the most common UK overseeding scenario.
More than 50% bare soil. Post-heavy scarification or complete renovation. Near-equivalent to sowing a new lawn.
Why seed rates change depending on your lawn's condition and what to expect after overseeding.
When overseeding a thin lawn, existing grass roots and blades compete with new seedlings for light, water, and nutrients. A light overseeding rate of 20 g/m² is sufficient because the existing grass protects the new seedlings from drying out too fast. On a bare or scarified lawn, that protection is gone — so a higher rate of 35–50 g/m² compensates for greater seedling mortality.
Perennial ryegrass is the fastest UK grass to germinate, typically showing green growth within 7–14 days in ideal conditions. Fine fescue and bent grass blends take longer — usually 14–28 days. A fully established, thick sward from overseeding takes 6–10 weeks in autumn conditions.
| Lawn Condition | Rate (g/m²) | Scarify? |
|---|---|---|
| Annual maintenance top-up | 15 – 20 g/m² | Light rake |
| Thin, sparse but grassy | 20 – 25 g/m² | Recommended |
| Patchy / post-summer wear | 35 g/m² | Yes |
| Large bare patches | 50 g/m² | Yes — essential |
| Post-heavy scarification | 50 – 70 g/m² | Already done |
| New lawn from scratch | 50 – 70 g/m² | Full prep needed |
UK-specific expert answers on timing, rates, scarifying, and getting the best results from overseeding.
Now you know exactly how much seed you need — choose a high-purity, certified UK grass seed that matches your existing turf for the most seamless results.
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