How to Repair a Lawn After Chafer Grub or Leatherjacket Damage (UK Step-by-Step Guide)

If your lawn is lifting like carpet, feels spongy underfoot, or birds are tearing chunks out of it, you’re likely dealing with chafer grubs or leatherjackets.

Once the pests are under control, the next question is always the same:

How do I repair the damage properly?

This guide walks you through the exact recovery process I use on UK lawns following grub infestations, including timing, tools, seed selection and how to prevent the problem returning.

Step 1: Confirm the Pests Are No Longer Active

Before you spend money on seed or topdressing, make sure the infestation has been addressed.

If you haven’t already identified the issue, read:
What’s Killing My Lawn? UK Guide to Chafer Grubs & Leatherjackets

Repairs are pointless if larvae are still feeding.

In the UK, treatment timing is critical:

  • Nematodes: late summer to early autumn

  • Severe infestations: may require professional intervention

Once activity has reduced and bird damage has stopped, you can begin recovery.

Step 2: Remove Dead Turf and Debris

Grub damage destroys the root system. The grass may still look green but will peel away easily.

You must remove all loose, dead material.

For small lawns:

For larger lawns:

For professionals:

These machines:

  • Remove dead thatch

  • Pull up loose turf

  • Create soil contact for new seed

This is the most important stage of the repair.

Step 3: Lightly Aerate the Surface

Grub-damaged lawns are often compacted underneath.

Light aeration helps:

  • Improve drainage

  • Encourage new root development

  • Increase seed success

For small areas:

For larger areas:

For professionals:
  • I use the Camon LA25. I’d recommend visiting your local garden machinery dealer if you’re interested in purchasing one.

If you’re considering powered options, SGS Engineering stock petrol aerators suitable for larger domestic lawns.

Step 4: Apply Topdressing

After scarifying and aerating, apply a light topdressing.

This:

  • Levels uneven areas

  • Improves seed-to-soil contact

  • Adds organic matter

Use a sandy loam lawn dressing rather than heavy compost. Apply at 3–5mm depth and brush into the surface.

Step 5: Overseed With a Suitable UK Lawn Seed

Choose a hard-wearing seed mix suited to UK conditions.

For general domestic lawns:

For shaded lawns:

For clay soils, wet lying areas/submersion tolerance, drought and free draining areas:

Apply at overseeding rate (typically 15–25g per m²).

Use a hand spreader or wheeled spreader for even coverage.

Step 6: Apply a Pre-Seeding Fertiliser

After grub damage, root systems are weak.

A pre-seeding fertiliser high in phosphorus supports root development.

Look for:

  • Higher middle number (e.g. 6-9-6 type ratios)

  • “Pre-seed” labelled products

Avoid strong high-nitrogen feeds at this stage.

Pre-seeders I’ve used include Nutrigrow Pre-Seeder and Pro-Kleen Pre Lawn & Seed Starter Fertiliser

Step 7: Water Correctly

Keep the seedbed:

  • Moist, not saturated

  • Lightly watered daily in dry weather

  • Protected from heavy foot traffic

Germination typically takes:

  • 7–14 days in spring

  • Slightly longer in cooler autumn conditions

When Is the Best Time to Repair Grub Damage in the UK?

Best windows:

  • April–May (after frost risk)

  • September (ideal)

Avoid:

  • Mid-winter

  • Peak summer drought

Autumn repairs generally establish better due to warmer soil and reduced stress.

Should You Just Re-Turf Instead?

In severe cases where:

  • 50%+ of lawn has failed

  • Soil level has dropped

  • Ground is heavily disturbed

Full renovation or re-turfing may be more cost-effective long term.

However, most grub-damaged lawns recover well with scarification and overseeding.

How to Prevent the Problem Returning

Repairing the lawn does not eliminate future infestations.

Long-term prevention plan:

  • Monitor adult chafer beetle activity in late spring

  • Apply nematodes in late summer

  • Improve drainage

  • Maintain healthy, dense turf

Healthy lawns are less attractive to egg-laying beetles.

Frequently Asked Questions

Will my lawn grow back after chafer grub damage?

If less than half the root system is destroyed, overseeding and feeding will usually restore it within one growing season.

Can I scarify straight after grub damage?

Yes — once larvae activity has reduced. Scarifying removes dead turf and prepares the surface for seed.

Is spring or autumn better for repair?

Autumn is generally better in the UK due to warmer soil and fewer weeds.

How long does it take for a lawn to recover?

Visible improvement appears within 3–4 weeks, but full thickening can take 8–12 weeks depending on conditions.

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