Bare Patches on Your Lawn? Here's What Causes Them – and How to Fix Them

Bare patches in your lawn can be a real eyesore, especially when you’re dreaming of a lush, green garden to enjoy all year round. Whether you’re spotting bald patches after mowing, noticing dry soil in summer, asking yourself why does my lawn look patchy, or simply wondering when to put grass seed down in the UK, you’re in the right place.

Let’s break down what causes bare patches on your lawn, how to treat them, and the best time to sow grass seed in the UK to bring your lawn back to life.

What causes patchy or thin grass, and how can I fix it

1. Dry weather
One of the biggest culprits. Lawns need consistent moisture to stay green and healthy. When the soil dries out, especially during summer, grass struggles to grow — leading to patchy areas.

2. Mowing too short (scalping)
If you notice bald spots appearing after mowing, your mower might be set too low. Cutting your grass too short can damage the plant and expose the soil, making it vulnerable to weeds and wear. Try keeping your grass between 25mm and 50mm (1–2 inches), and raise the cut during dry spells.

3. Wear and tear
Frequent foot traffic, furniture left in place, and general garden use can all stress grass, especially in high-use areas. If furniture is regularly kept on the same patch of grass, try moving it around to avoid killing off the turf underneath.

4. Dog urine
Circular patches with bright green edges and a dead centre? Likely your furry friend. While training them to go elsewhere is ideal, diluting the area with water immediately after can reduce damage. (For more information: Pets on your lawn – GreenThumb)

5. Lack of sunlight
Grass needs light to grow. If you’ve got bare patches in shaded areas, try pruning back overhanging trees or shrubs, and regularly removing items like trampolines and plant pots to let in more light.

6. Lawn disease or pests
Sometimes the problem runs deeper. If you're noticing odd patterns, discoloured patches, or rapid deterioration, it could be a lawn disease or insect infestation. Your local GreenThumb Lawn Operative can help diagnose and treat the issue.

7. Petrol or oil leaks from mowers
Check your mower for leaks. Even a small fuel spill can burn the grass, leaving unsightly bald patches. Always refuel your mower off the lawn and keep an eye out for damaged pipes or seals.

When to Reseed Lawn in the UK

When is the best time to overseed my lawn? The ideal times are spring (March–May) and early autumn (late August–October) when the ground is warm and moist. These conditions give seeds the best chance to germinate and establish strong roots.

Whether you're reseeding a lawn, overseeding grass, or just adding a bit of coverage after scarifying, getting the timing right is key. In Scotland, this window may shift slightly depending on temperatures—watch for consistent ground temps above 8°C.

Can I Just Throw Grass Seed Down on an Existing Lawn?

It’s a common question: Can I overseed an existing lawn without digging it up? Yes! But for best results, follow these simple steps:

How to Repair Bare Patches in the Lawn (UK Guide)

Choosing the Right Seed

If a bare patch is already present, effective lawn patch repair starts with choosing a lawn seed that closely matches your existing grass to ensure the most seamless and natural-looking blend.

• For fine-bladed lawns (like fescues), choose a fine lawn seed mix.

• For hard-wearing, family lawns (often ryegrass-based), a general-purpose lawn seed will do the job.

Remember — quality matters. Investing in a high-quality seed will usually give better long-term results, which is why we recommend our Overseeding service.

How to Overseed Your Lawn (Step-by-Step)

1. Prepare the Area
   Rake away any dead grass, moss, or debris to expose bare soil and ensure good seed-to-soil contact. Scarify if necessary.

2. Choose the Right Time
   Sow seed when the ground temperature is above 8°C – typically spring or early autumn – and when there’s adequate warmth and moisture.

3. Spread the Seed Evenly
   Follow the seed packet’s instructions for sowing rates. You can use a spreader for large areas or sow by hand for patch repairs.

4. Ensure Seed-to-Soil Contact
   Lightly rake the seed into the surface and gently firm it down with your feet or a roller to press it into the soil.

5. Water Regularly
   Keep the soil moist (not soaked) to encourage germination. If it hasn’t rained, water daily until the seedlings are established.

6. Protect the Seedlings
   Avoid heavy foot traffic while the new grass establishes. Continue mowing your lawn as needed, but raise the mower height to protect young shoots.

7. Aftercare
   Once the new grass reaches the two-leaf stage, you can gradually return to your normal mowing height. Avoid cutting too short too soon.

Best Time to Overseed Lawn UK – Quick Guide

Too Much Lawn Seed?

A quick note: More isn't always better. Using too much lawn seed can lead to overcrowded, weak grass plants. Stick to the recommended seeding rate on your seed packet or ask your local GreenThumb expert.

How GreenThumb can help?

We have an excellent Top Dressing and Overseeding Service

Our Top Dressing is a bespoke, 100% organic product, made up of green waste. It's used for overseeding to nourish and protect developing grass plants and to also enrich sandy soil or improve clay soil.

• Our Diamond Green seed is a blend of Fescue and Perennial Rye grasses which adapt specifically to any environment. It has fast establishment, improves colour and a greater tolerance to drought, shade, disease and close mowing.

It’s also important to consider that bare patches can be caused by lawn disease. Your GreenThumb Lawn Operative will be able to identify any common lawn disease . If you have any concerns, please make your branch or lawn operative aware.

Our treatments will do wonders for your lawn, but we require a little effort from you to make your lawn shine.

Get in touch today: Find your local GreenThumb branch