How to Fix a Patchy Lawn: The Pro’s Guide

Recommended watching — Backyard Bushveld, via YouTube.

A thick, even lawn is built from the soil up — not sprayed on.

A patchy lawn isn’t a lost cause. Bare spots, thin growth and worn tracks almost always come down to one of a handful of causes — and every one of them is fixable. Sort out the cause, give the grass what it needs to knit back together, and you’ll have a lawn that’s thicker, greener and far tougher than before. Here’s how the pros do it.

Why lawns go patchy

Before you reach for a bag of seed, work out why the lawn failed in that spot. Fix the cause or the patch will simply return. The usual suspects are compacted soil that roots can’t push through, deep shade, poor drainage, heavy foot traffic, or pests and disease feeding below the surface.

Diagnose firstDig a small plug from a bare patch and look. Dry, rock-hard soil means compaction. Grey, sour-smelling soil means it stays too wet. Chewed roots or fat white grubs mean a pest problem you’ll need to treat before reseeding.

What you’ll need

Good preparation does most of the work. Get these together before you start and the job goes quickly.

Lawn dressing for levelling and topdressing

Close-up of quality lawn seed in the hand

A spring-tine or scarifying rake — to tear out dead thatch and open the surface.
Quality lawn seed or plugs — matched to your existing grass and your sun/shade conditions.
Lawn dressing or sifted topsoil — to level low spots and cover new seed.
A starter fertiliser — higher in phosphorus, to drive strong early root growth.

How to repair a patchy lawn, step by step

Scarifying: raking dead thatch out of a lawn

Work in order — each step sets up the next.

Rake out the dead growth. Scarify the patch hard to remove thatch and loosen the top layer of soil, so seed makes contact with bare earth.

Relieve compaction. Fork the area over or push a garden fork in deep and wiggle it, every 10–15cm, to open the soil and let roots and water down.

Level the low spots. Fill dips with lawn dressing and rake it smooth, so water doesn’t pool and the mower runs even.

Sow at the right rate. Spread seed evenly at the rate on the bag — too thin leaves gaps, too thick and seedlings choke each other. For plugs, space them a hand-width apart.

Topdress lightly. Cover the seed with a thin scatter of dressing — just enough to hide most of it. Seed buried too deep won’t come up.

Water little and often. Keep the surface constantly moist with short, frequent waterings until the seed is up and established. Letting it dry out once can kill the lot.

After it’s established

Wait until the new grass is rooted before the first mow.

Keep off the repaired patch until the grass is a few centimetres tall and rooted in — a gentle tug should meet resistance. Take the first cut on a high mower setting, removing no more than a third of the leaf. Once it’s growing away strongly, fold it into your normal feeding programme and it will thicken up over the season.

Common mistakes to avoid

Sowing at the wrong time. Warm-season lawns knit back fastest in spring and early summer when the soil is warm. Seed sown into cold soil just sits and rots.

Letting new seed dry out. New seed has no roots to fall back on. Miss a watering in the heat and you’ll be starting over.

Mowing too soon or too short. Cutting young grass hard rips out shallow-rooted seedlings and undoes the repair.

Everything you need to fix your lawn

Quality seed, lawn dressing, feed and the right tools — the same kit the pros rely on.

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