Why is my lawn full of holes and dead patches?

Lawn damage looks similar from a distance and has quite different causes. Lifting the turf at the edge of a damaged patch usually answers the question in ten seconds.

What you'll need

• Spade or trowel
• Grass seed (optional)
• Water (optional)

Step by step

1. Lift a patch of turf at the edge of the damage.If it peels back like a carpet with no roots and there are white C-shaped grubs beneath, you have chafer grubs or leatherjackets.
2. Look at what is doing the digging.Birds, badgers and foxes tear up turf to get at grubs. The animals are a symptom; the grubs are the cause.
3. Identify ant activity by the fine soil mounds.Small heaps of very fine soil, usually in dry weather. Ants rarely damage the grass itself — brush the heaps out when dry.
4. Identify dog urine patches by their shape.Round yellow or brown patches, often with a ring of lusher green around the edge. Water the spot heavily immediately after to dilute it.
5. Consider drought and compaction before pests.Patches in high-traffic areas or over buried rubble are far more common than pests, and they recur in the same places every summer.
6. Treat grubs biologically if the infestation is significant.Nematodes applied to moist soil at the right time of year are the main option. Timing matters and is specific to the pest.
7. Repair the damage by reseeding.Rake out the dead material, loosen the soil, add topsoil, sow seed and keep it consistently damp for three weeks.
8. Improve the lawn's general health.A vigorous well-fed lawn with good drainage recovers from pest damage far better than a stressed one, and is less attractive to grubs.

Tips

• A lawn that recovers each year is not necessarily a problem. Some grub activity is normal and only becomes serious at high densities.
• Nematode treatments must be applied when the target pest is at the right life stage and the soil is warm and moist. Applying at the wrong time achieves nothing.
• Dog urine damage is prevented far more easily than repaired — watering the spot immediately dilutes it before it burns.

Common mistakes

• Treating the birds rather than the grubs — The birds are there because of the grubs. Deterring them does nothing about the cause of the damage.
• Assuming every dead patch is a pest — Drought, compaction, dog urine and buried rubble are far more common causes and recur in the same spots each year.
• Applying nematodes at the wrong time — They only work against a specific life stage in warm moist soil. Applied outside that window they achieve nothing.

Questions people ask