Why Is My Lawn Turning Yellow? Causes and How to Fix It

A lush green lawn is something every homeowner wants, so it can be frustrating when patches of grass suddenly begin turning yellow. The good news is that yellow grass doesn't always mean your lawn is dying. In many cases, it's simply a sign that something isn't quite right.

We spoke to A View Turf and they say by identifying the cause early, you can often restore your lawn before permanent damage occurs.

Common Reasons Your Lawn Is Turning Yellow

Patchy yellow grass can be caused by a range of issues, from watering habits to pests and nutrient deficiencies.

Here are some of the most common causes.

1. Overwatering

Too much water can be just as harmful as too little.

When soil remains constantly wet, grass roots don't receive enough oxygen, making the lawn weak and prone to disease.

Signs of overwatering include:

• Soft or soggy ground
• Yellowing grass across large areas
• Mushrooms appearing in the lawn
• Slow growth
• Standing water after irrigation

Allow the lawn to dry slightly between watering sessions and water deeply rather than frequently.

2. Underwatering

Grass needs consistent moisture, especially during hot Australian summers.

A lawn that isn't receiving enough water may develop:

• Yellow or brown patches
• Dry, brittle blades
• Soil that feels hard
• Slow recovery after being walked on

Water deeply in the early morning to encourage deeper root growth.

3. Nutrient Deficiency

Lawns require nutrients to maintain healthy growth.

Nitrogen deficiency is one of the most common reasons grass loses its rich green colour.

Other signs include:

• Slow growth
• Thin grass
• Pale green or yellow leaves
• Reduced recovery after mowing

Applying a quality lawn fertiliser at the appropriate time of year can often restore colour and vigour.

4. Soil Compaction

Heavy foot traffic, children playing, pets, or frequent mowing can compact the soil.

Compacted soil restricts water, nutrients, and oxygen from reaching the roots.

Aerating the lawn can help relieve compaction and improve overall health.

5. Lawn Disease

Several fungal diseases can cause yellowing grass, particularly during warm, humid weather.

Common symptoms include:

• Circular yellow patches
• Brown rings
• Slimy or mouldy areas
• Rapid spreading after rain

If disease is suspected, early treatment is important to prevent further damage.

6. Pest Damage

Some lawn pests feed on grass roots or leaves, causing sections of lawn to turn yellow.

Common Australian lawn pests include:

• Lawn grubs
• Armyworms
• Beetle larvae
• African black beetles

If birds are frequently pecking at your lawn, they may be searching for grubs beneath the surface.

7. Dog Urine

Small yellow patches surrounded by dark green grass are often caused by dog urine.

The high nitrogen concentration burns the grass in the centre while fertilising the surrounding area.

Watering the area immediately after your dog urinates can help reduce damage.

8. Mowing Too Short

Scalping your lawn removes too much of the leaf blade and places stress on the grass.

This makes it harder for the lawn to photosynthesise and recover.

As a general rule:

• Never remove more than one-third of the grass height in a single mow.
• Keep mower blades sharp.
• Adjust the cutting height for your turf variety.

9. Poor Drainage

Waterlogged lawns often develop yellow grass because roots cannot access enough oxygen.

If water pools after rain, improving drainage or aerating the soil may help restore healthy growth.

10. Seasonal Changes

Some turf varieties naturally slow their growth or lose colour during cooler months.

Warm-season grasses such as Buffalo, Couch, and Kikuyu often become less vibrant during winter before greening up again in spring.

How to Restore a Yellow Lawn

The best treatment depends on the underlying cause.

General steps include:

• Adjust your watering schedule.
• Fertilise if nutrients are lacking.
• Aerate compacted soil.
• Improve drainage where necessary.
• Treat pests or lawn disease promptly.
• Raise your mowing height.
• Repair damaged areas with new seed or turf if required.

Addressing the root cause is far more effective than simply watering more or applying additional fertiliser.

Prevent Yellow Grass in the Future

Good lawn care goes a long way towards preventing problems.

Maintain a healthy lawn by:

• Watering deeply but not too often
• Fertilising seasonally
• Mowing at the correct height
• Aerating compacted areas
• Monitoring for pests and disease
• Keeping mower blades sharp
• Improving soil health with organic matter where needed

Regular maintenance helps your lawn stay greener and recover more quickly from stress.

When to Call a Lawn Professional

If your lawn continues turning yellow despite proper care, or large sections die unexpectedly, it may be time for a professional assessment.

A lawn care specialist can identify the underlying cause, recommend appropriate treatments, and help restore your lawn before the damage becomes permanent.

Final Thoughts

Yellow grass is usually your lawn's way of telling you that something needs attention. Whether it's watering, nutrition, pests, disease, or drainage, acting early gives your lawn the best chance of recovery.

With the right diagnosis and ongoing maintenance, most lawns can regain their healthy green appearance and continue thriving throughout the year.

Frequently Asked Questions

Can yellow grass turn green again?

Yes. If the roots are still healthy and the underlying issue is corrected, most lawns will recover and return to their normal green colour.

Does fertiliser fix yellow grass?

If the problem is caused by nutrient deficiency, fertiliser can help. However, if the cause is overwatering, pests, disease, or poor drainage, fertiliser alone won't solve the issue.

How often should I water my lawn?

Most established lawns benefit from deep watering one or two times per week, depending on rainfall, soil type, and the season.

Why is my lawn yellow after mowing?

This may be caused by mowing too short, using blunt mower blades, or exposing older stems that receive less sunlight. Raising the mowing height often improves the lawn's appearance.

Should I replace yellow patches with new turf?

Only after identifying the cause. Installing new turf without fixing the underlying problem may result in the new grass developing the same issues.