First, Work Out What You're Dealing With

Before you reach for the rake, take a moment to look closely at the damage. A lawn that has gone straw-coloured and crispy after a dry summer is often simply dormant, not dead. Grasses respond to drought by shutting down top growth and letting the leaves brown off, while the crowns and roots below the surface stay alive, waiting for rain.

There's a simple test. Grab a tuft of brown grass and give it a gentle tug. If it holds firm and resists, the plant is still rooted and dormant, and it should green up within a fortnight of steady rain. If it lifts away easily with no resistance, that patch has died and will need reseeding. You'll usually find a mix of both across a UK lawn, with the shallow, compacted areas suffering worst.

Once you know which is which, you can plan your repairs properly rather than wasting seed and effort on ground that only needed water and time.

Pick the Right Moment to Start

Timing matters more than anything else with lawn repair. The ideal window in most of the UK runs from late August through to mid-October, when the soil is still warm from summer but regular rain has returned and the fierce heat has passed. Soil temperatures above about 8–10°C mean grass seed germinates quickly and young plants establish before winter.

If you're in a dry spell, wait. Working brittle, bone-dry turf tears the crowns and does more harm than good. Give the lawn a good soak the day before you start, or wait for a decent bout of rain. Spring is a workable second choice, but autumn gives you warmer soil, fewer weeds germinating and less pressure from drought.

Scarify Lightly, Then Aerate

Start with a mow, setting the blades to around 25–30mm and collecting the clippings. Then scarify, but gently. The aim is to lift dead thatch, moss and matted stubble, not to strip the lawn back to soil.

• Work in one direction with a spring-tine rake or scarifier, then decide whether a second pass at right angles is needed.
• Go over thin or newly recovered areas only once — these have the least to spare.
• Collect everything you rake out. Leaving it in place smothers the grass you're trying to save.

Next, deal with compaction, which is the hidden culprit on many allotments and family lawns where foot traffic concentrates. Push a garden fork into the turf to a depth of 8–10cm, spacing the holes roughly 10–15cm apart, and wiggle it to open the soil. For heavier clay, hire a hollow-tine aerator for a morning and remove the plugs. Brush a sandy top dressing into the holes afterwards — around 1–2kg per square metre is plenty — which improves drainage and gives seed something to root into.

Overseed the Bare Patches

Now for the bare spots. Choose a seed mix suited to how you use the lawn: a hard-wearing blend with perennial ryegrass for family gardens and allotment paths, or a finer fescue and bent mix for a smarter, lower-traffic lawn.

• For overseeding a thin lawn, sow at roughly 15–20g per square metre.
• For genuinely bare patches, increase to 25–35g per square metre.
• Mix the seed with drysand or fine compost to spread it evenly and see where you've been.
• Rake it in lightly so the seed sits 5–10mm deep — any deeper and it won't make it to the surface.
• Firm the area with the back of a rake or by shuffling across it in flat shoes, so the seed makes good contact with the soil.

A little protection helps enormously. Netting or a few criss-crossed bamboo canes will keep blackbirds and cats off while the seed is vulnerable.

Water Consistently While It Establishes

Newly sown grass is far less forgiving than an established lawn, and inconsistent watering is the single most common reason patch repairs fail. For the first fortnight, keep the surface moist at all times. That means a light sprinkle of around 5mm once or twice a day, depending on the weather, using a can with a fine rose so you don't wash the seed away.

Germination usually takes 7–14 days. After that, ease off to a deeper soak of 10–15mm twice a week, which encourages roots to travel downwards rather than sitting near the surface. Early morning is the best time — evening watering leaves the grass damp overnight and invites disease. Once the new grass has been cut three or four times, you can treat it like the rest of the lawn.

Feeding and Mowing From Here On

Don't reach for a high-nitrogen feed on a drought-stressed lawn; it pushes soft growth the roots can't support. Instead, use an autumn lawn feed with lower nitrogen and more phosphorus and potassium to build root strength and hardiness. Apply it after the new seed has established, not before.

Mowing needs patience too. Leave new grass until it's around 6–8cm tall, then cut no more than a third of the leaf at a time with sharp blades. Over the following seasons, raising your summer cutting height to 40–50mm will shade the soil, reduce moisture loss and leave the lawn far better equipped to shrug off the next dry spell.