Common Lawn Problems Explained

How it looks

Lawn turns dull green then straw-coloured. Footprints remain visible in the grass for longer than usual. The grass feels crispy underfoot.

Cause

Insufficient water, typically during summer. Most common in lawns on shallow or sandy soils.

Treatment

Do not panic — most cool-season grasses go dormant rather than die. They recover once rain returns. If you want to water, soak deeply once or twice a week rather than frequent light watering. Do not fertilise a drought-stressed lawn.

How it looks

Hard surface that feels solid underfoot. Water pools on the surface or runs off rather than soaking in. Grass grows slowly, moss appears.

Cause

Heavy foot traffic, vehicles, or clay-heavy soil. Compaction reduces the air spaces roots need, impairs drainage, and favours moss over grass.

Treatment

Hollow-tine aerate across the affected area. Brush sharp sand or top dressing into the holes. Repeat annually in autumn. Avoid mowing or walking on the lawn when waterlogged.

How it looks

Lawn feels spongy when you walk on it. Water beads on the surface. Growth is slow. You can see a brownish fibrous layer at the base of the grass.

Cause

Thatch is a layer of dead and living organic matter (stems, roots, debris) that accumulates between the grass and soil. A thin layer (under 1 cm) is fine; more than this blocks water and nutrients.

Treatment

Scarify to remove thatch — use a powered scarifier for anything beyond a light build-up. See How to Get Rid of Moss for the scarification process (same procedure applies to thatch alone).

How it looks

Pink or red thread-like strands on the grass blades, sometimes a pinkish-red fluffy growth. Irregular patches of affected grass, often tan or straw-coloured at the centre.

Cause

Fungal disease (Laetisaria fuciformis). Most common in late summer and autumn. Almost always linked to nitrogen deficiency — the fungus attacks weak, poorly-fed grass.

Treatment

Feed the lawn with a nitrogen-containing fertiliser. This is usually sufficient — red thread rarely kills grass permanently, and healthy well-fed turf resists it. Fungicide is rarely necessary. Improve drainage and air circulation if it recurs every year.

How it looks

Small orange-brown circular patches in autumn or winter, sometimes enlarging. A white-grey fluffy growth at the patch edges in wet conditions. Often appears after the first frost or after snow melts.

Cause

Fungal disease (Microdochium nivale). Favoured by mild, damp autumn conditions, overuse of nitrogen late in the season, and poor drainage.

Treatment

Improve drainage and air circulation. Avoid high-nitrogen fertilisers after August. Fungicide for severe outbreaks. Remove infected debris. Overseed patches in spring.

How it looks

Small (golf-ball to saucer-sized) bleached or tan patches. Sometimes a web of white threads (mycelium) visible in early morning dew. Worse in warm, humid weather.

Cause

Fungal disease (Clarireedia spp.). Usually indicates low nitrogen and drought stress on fine-leaf grasses.

Treatment

Apply a nitrogen fertiliser. Ensure the lawn is not under drought stress. Improve drainage. Fungicide for severe or persistent outbreaks.

How it looks

Yellow-brown patches appearing in autumn. Turf feels spongy or lifts easily — sometimes pulls up like a carpet revealing grey-brown grubs underneath. Birds (starlings, rooks) or foxes pecking intensively at the lawn.

Cause

Leatherjackets are the larvae of crane flies (daddy long legs). They feed on grass roots from late summer through spring.

Treatment

Apply nematodes (Steinernema feltiae) in late summer to early autumn when soil temperature is above 10 °C and moist. Water them in well. Reseed damaged patches after treatment. Nematodes are the only practical control for most gardens.

How it looks

Brown patches that lift easily, with white C-shaped grubs visible in the soil. Birds and foxes digging up turf, often in May–June or September.

Cause

Larvae of chafer beetles (garden chafer, welsh chafer). Damage is often more visible in spring as larvae feed heavily before pupating.

Treatment

Apply nematodes (Heterorhabditis bacteriophora) in June–July when soil temperature is 12–20 °C and conditions are moist. Reseed damaged areas in autumn.

How it looks

Circular or arc-shaped rings of darker green grass, sometimes with mushrooms at the ring edge. The grass inside the ring may be dead or, in some types, intensely green.

Cause

Underground fungal mycelium breaks down organic matter in the soil. Three types: Type 1 kills the grass, Type 2 stimulates growth, Type 3 is mainly cosmetic with mushrooms at the surface.

Treatment

Aerate intensively inside and beyond the ring to improve drainage and disrupt the mycelium. Apply a wetting agent to help water penetrate the dry, hydrophobic soil often found inside rings. Complete eradication is difficult — excavation and soil replacement is needed for Type 1 (killing) rings.

How it looks

Pale green or yellow lawn, slow growth, older leaves yellowing first. Uniform paleness across the whole lawn rather than patches.

Cause

Insufficient nitrogen, usually from lack of feeding or from nitrogen being leached by heavy rain.

Treatment

Apply a spring or summer feed (high-nitrogen). Results should be visible within 7–14 days.

How it looks

Dandelions, clover, plantain, speedwell, or other broad-leaved plants growing in the lawn. They compete with grass for space and nutrients.

Cause

Weeds establish in thin, weak grass — often after drought, wear, or poor nutrition. They spread from seeds carried by wind or birds.

Treatment

Apply a selective lawn herbicide (or weed & feed product) when weeds are actively growing and grass is not drought-stressed. Spot-treat individual weeds rather than blanket-treating the whole lawn. A well-fed, thick lawn is the best long-term weed defence.