Why is My Lawn Turning Yellow? 7 Reasons Plus Solutions

You’ve put in the time, effort, and care to grow a beautiful green lawn. So it’s frustrating to suddenly see your lawn turning yellow. I’ve been there, too, seeing a portion of my lawn turning yellow during the winter month in Coffs Harbour. The grass stops growing, starts wilting, drooping, or even burning at the tips… all while showing that dreaded patch of pale yellow. 

It's always tough figuring out what's causing the problem at first glance. There are several common reasons your grass might be losing its colour. I've gathered the best solutions to restore your lawn to its lush, green self.

7 Common Causes of Yellowing Lawn

Having been there, I’ve consulted the experts and done the research so you don’t have to, here is a list of the most common causes of a lawn turning yellow:

1. Improper Watering 

The amount of water you use to water your lawn plays a vital role in maintaining a beautiful green lawn. Common bad watering practices that can lead to adverse grass health, include underwatering, overwatering, and irregular watering during extreme temperatures. I'll explain the most common poor practices below:

Underwatering

If the lawn doesn't get enough water, it slowly dies, and this can start with yellow patches. Here's why…

Grass blades wilt and turn pale green or yellow due to drought stress. Some plants begin advanced yellowing and severe wilting within ten days of drought stress.   

When soil moisture depletes, there is reduced microbial activities, less soil mineralization and soil diffusion. Therefore, essential nutrients for the plants, which includes nitrogen, phosphorus and potassium, become scarce. This happens especially in grasses with poorly developed, shallow roots. 

Overwatering 

Overwatering your lawn grass also causes roots to rot. This encourages fungal growth, leading to yellowing grass and lawn patches. Its also worth noting that soil-borne fungi can directly cause roots to rot, and therefore grass blade discolouration.

An additional mechanism whereby overwatering cases yellowing is when excess water leaches nutrients from the soil. The soil becomes saturated and diluted when it drains off, valuable nutrients leach away with the water. This changes the soil structure and affects the plants rooted in it.

The end result is nutrient deficiencies that reflect in the colour of the grass blades.

Waterlogged soil from over-irrigation or excessive rain,  can also deprive grass of necessary air intake. 

Overwatering turfgrasses can cause oxygen starvation, root damage, decay and plant death – in fact, it kills plants faster than underwatering. If the water doesn't drain quickly enough, the lawn grass may start dying due to lack of aeration. A quick way to know if the soil is over-watered is to stick a screwdriver in it. If it is easy to push in to full depth you might have an overwatering problem.

Good soil drainage is necessary to limit the impact of overwatering. This can be achieved by topdressing with sand, installing subsoil drainage or grading a slight slope in your lawn.

 

2. Adverse Weather and Unsuitable Lawn Grasses

While some lawn grasses perform just as well in any region, some grasses droop and yellow up due to summer stress in semi-tropical or tropical climates. 

If you live in tropical places like northern Queensland or New South Wales, you want to steer clear of cool-season grasses like Kentucky bluegrass, Bentgrass, ryegrass and fescue. While I have seen a few cool season grasses in some lawns here in Coffs, they're high-maintenance grasses during autumn or other off-spring seasons. They'll also require more water and maintenance to keep alive in Summer. 

Bentgrass, for instance, have short stolons that can't reach out to nutrients during drought periods. By the autumn months of March to May, these grasses (Kentucky especially) break and change into yellow, red, and orange colours as they prepare for winter.

Winter frosts can also cause your grass to discolour. Research shows that some grasses tend to yellow, wilt, and curl when exposed to extreme cold and drought stress.   

Classic frost burn pattern:

Dormancy is another cause of yellowing which occurs mainly in warm season grasses during winter, when cloudy days cause limited photosynthesis in grass. This effect is exacerbated by falling soil temperatures. Photosynthesis drives nutrient production in plants. A higher temperature increases photosynthesis rate. Conversely, a decline in sunshine and temperature leads to nutrient deficiencies, which may reflect in the colour of the lawn.

Dormant lawn...

3. Nitrogen Deficiencies or Overdose 

Overwatering, too much rain, or over-irrigation can cause essential nutrients like nitrogen to leach out of the soil. 

When uncontrolled, nitrogen deficiency often results in chlorosis, a condition where plants don't produce enough chlorophyll. Chlorophyll is the green pigment found in the chloroplasts of plants. Without chlorophyll production, the grass cannot photosynthesise appropriately. Then the grass becomes yellow, has stunted growth and dies eventually. 

Nutrient deficient lawn, looks ok from a distance:

But yellow and strawy up close...

Excess nitrogen can result in "fertiliser burn.” This kind of nutrient toxicity causes the grass tips to turn yellow or brown due to scorching. Additionally, an overdose can lead to excessive growth that the roots cannot support, weakening the grass and making it more prone to yellowing.

 

4. Soil Hardness

Soil hardness, or soil compaction, occurs in dry seasons and on lawns with heavy traffic. Compact soil can lead to a chain of issues: increased soil hardness → nutrient deficiencies → yellowing and dry lawn grasses → bald patches → lawn death. 

Grass roots find it hard to take nutrients up in compact soil. Also, hard lawn soil means water is not able to penetrate. When you water or when it rains, the lawn experiences a runoff of surface water rather than water penetration.  

And what causes soil hardness? Well, you may experience soil hardness on lawns where there is high foot traffic or if you pass heavy machinery – lawnmowers, tractors, or construction vehicles – on them. Lawn soil with high clay content also tends to compact easily. All it needs is a mix of rain and sun. Then, the ground firms up and it becomes almost impossible for plants to get nutrients from. 

5. Mowing Practices 

If your grass turns yellow or brown within a few days of mowing, it's usually due to common bad mowing practices. Some mowing practices can spread diseases, injure the grasses, stress your grass out and lead to a yellowing “protest.” 

Practice number one… 

You are not following the one-third mowing rule. That is, you're cutting more than a third of the grass height. Cutting a low lawn is always a stress to avoid. Furthermore, a negative shock is guaranteed if you trim more than 30% of the grass height. Grass mowing removes moisture from the plants. Overdoing it is an absolute overkill for them. 

And secondly, mowing grass plants too early after winter can cause yellow patches or even generalised discolouration. Of course, you're already in the starting blocks in spring and can hardly wait to get your yard back in shape after the long winter months. 

However, you should take your time with the first lawn mowing. After the winter dormancy, your lawn needs some time to return to its former strength. If you mow it before the growth returns, it will take longer to bounce back and may turn yellow due to the strain.

And finally…

If you notice that only the upper part of the leaves is yellowish-brownish, the cause is most likely the lawnmower blades. Mowing the lawn with rusty or blunt blades never does good on the grass. The cuts aren't done cleanly, and you'll have a lot of bad jagged cuts on the grass, which will reflect in bad patches of yellow or brown colour. This will take time to “heal” or grow out of. 

Let the grass be, and go take care of your blades.  As a rule, you have to sharpen the blades once after every 20-25 hours of use. 

6. Pest and Disease Issues

If your lawn is turning yellow, pests and diseases could also be the culprits. 

Insects like African black beetles, army worms, bill bugs, and chafer grubs are common pests in Australian lawns and turfs. They have nothing much to feed on but munch on the grass blades and roots. They disrupt their ability to soak up nutrients and water. Army worms can leave you with unsightly yellow patches, dead spots, hollowed out stems, and other discolourations. 

A soapy water test is an easy way to test for army worms feasting on your lawn. Simply pour some soapy water in patches with discoloured grasses or anywhere you suspect there's an infestation. After a few minutes, worms in the grass will start to surface. 

Even microscopic nematodes can cause similar damage. On the disease front, fungal infections like dollar spot or rust thrive in wet, humid conditions, leading to yellow or brown patches on your lawn. Mould and mildew, like powdery mildew or snow mould, can also cause yellowing by blocking sunlight or attacking the grass after a heavy frost.

Classic case of rust, which usually resolves itself:

It’s not just bugs and fungi; even bacterial infections can leave your grass looking worse for wear, with wilting and yellowing as tell-tale signs. When grass is weakened by pests or disease, it becomes more vulnerable to other stressors like drought or poor soil conditions, making the yellowing even worse.

 

7. Pet Urine and Chemical Burns

Your four-legged friend probably enjoys playing on the lawn. But it's true that pets can also damage the lawn by causing it to turn yellow. It's the result of high traffic and over-fertilisation of playing spots. 

Urine from pets with high protein diet can contain quite high nitrogen levels, which can cause yellow patches in the lawn. Don't panic, though. The grass often repairs itself. If you see where your pet has urinated, it helps to water that spot well and thus dilute the nitrogen.

 

How to Fix a Yellowing Lawn 

Yellow spots in some cases, like the winter, after mowing, or during drought periods, are completely usual and not a problem. You can prevent or fix these unsightly spots with a few simple steps. 

1. Adjust Watering and Irrigation

Proper watering is critical to a healthy, greener and fast-growing lawn. It's key to ensure your lawn is getting the right amount of water, especially during dry periods. But don't overdo it. 

The table below provides a recommended watering frequency and duration for different types of grasses, from cool season to tough tropical grasses:

Grass Type	Watering Frequency	Watering Duration	Notes
Cool Season Grasses (e.g., Kentucky Bluegrass, Fescue)	2 to 3 times per week	20 to 30 minutes per session	Water early in the morning; adjust based on weather conditions.
Warm Season Grasses (e.g. Couch, Buffalo, Zoysia)	1 to 2 times per week	30 to 45 minutes per session	Water early in the morning; adjust based on weather conditions.
Tropical Grasses (e.g., Kikuyu)	1 to 2 times per week	30 to 45 minutes per session	More drought-tolerant; water less frequently but ensure deep watering.

Tips: 

• Too much or too little water can lead to yellowing. Consider using an irrigation system to maintain consistent moisture levels. Pop up sprinklers, soaker hoses, or crawling sprinklers can maintain consistent moisture levels. 
• You could also use tap timers—whether analogue or smart Bluetooth-controlled—for better water management. 

2. Mowing Practice 

If the lawn turns yellow shortly after mowing, this usually indicates blunt mower blades. Dull blades tear the grass instead of cutting it cleanly, causing stress and yellowing or browning from the cut injuries. 

Mow with sharp blades. 

It is best to grind the blades with a whetstone before each mowing and sharpen them yearly in a specialist workshop.

Make sure the mower blades are sharp and free of burrs and edges to avoid fraying the grass tips. To get an even cleaner cut, consider upgrading your rotary mower to a cylinder or reel mower. Their sharp blades make clean cuts and can reduce the likelihood of spreading lawn disease, which can occur when dull or dirty rotary mowing blades tear the grass, leaving jagged edges that are more susceptible to infection.

Mow Less by Using PGRs

Frequent mowing, especially too short, can lead to scalping and yellowing. If higher, more regular mowing isn’t an option for you, consider using plant growth regulators (PGRs). PGRs slow the growth of the grass, allowing you to mow less frequently while still maintaining a healthy lawn. 

 

3. Aeration and Soil Care

If your lawn soil is hard and compact, highly trafficked or contains clay soil, you have a physical job to do. But using the right equipment can make your job so much easier. 

Aerating your lawn can improve root health and free the grasses from nutrient suffocation. We recommend using the Draper Tools Manual Core Lawn Aerator for isolated sections or if you have a very small lawn. However, the tow-behind aerator works better if you have a large lawn.

 

4. Fertilisation, Iron Supplementation and Soil Treatment

As I mentioned, lawn yellowing is often a sign of nutrient deficiencies, particularly nitrogen or iron. Regular and proper fertilisation and iron supplementation ensure the soil has the right pH and nutrient balance and can keep your lawn healthy and green.

This lawn is growing in pH 8.5 soil:

While there’s not much you can do to increase photosynthesis in cooler, cloudy conditions, spray-on turf pigments offer a practical solution to maintain the appearance of warm-season grasses during winter dormancy. Applying these pigments in autumn, before plant growth stops, can keep your lawn looking good even when growth slows down.

Below is a fertilisation guide for lawns suffering from nutrient deficiencies from conditions such as soil leaching:

Fertiliser Type	Application Frequency	Nutrient Ratio	Best Time of Year to Apply	Usage Tips
Slow-Release fertiliser	Every 6 to 8 weeks	Balanced (e.g., 10-10-10)	Early Spring, Late Autumn	Provides nutrients gradually, reducing leaching risk.
Granular fertiliser	Every 4 to 6 weeks	High Nitrogen (e.g., 20-5-10)	Spring, Early Summer	Use in moderate amounts to avoid excessive runoff.
Liquid fertiliser	Every 2 to 4 weeks	Balanced or High Nitrogen (e.g., 15-15-15 or 30-0-0)	Throughout Growing Season (Spring to Autumn)	Provides quick nutrient uptake; avoid overuse
Organic fertiliser	Every 6 to 8 weeks	Varied (e.g., compost or manure)	Spring, Autumn	Improves soil structure and reduces leaching.
Water-Soluble fertiliser	Every 2 to 4 weeks	High Phosphorus (e.g., 10-20-10)	Early Spring, Early Autumn	Enhances root development; use with caution to prevent runoff.

Tips on Choosing the Right fertiliser

• Choose a fertiliser based on your lawn's condition. High nitrogen options are great for nutrient-deficient lawns.
• Slow-release fertilisers offer long-lasting results, reducing the need for frequent applications and saving money.
• If you want to avoid chemical fertilisers you can opt for organic fertilisers to improve soil health and without chemical use.
• For a quick fix, use liquid fertilisers for fast nutrient uptake but be cautious of overuse.

Warning and Recommendations 

• Remember, over-fertilisation can lead to burns, taking you back to the same issue you're treating. 
• Use a slow-release or organic fertiliser. I recommend using a lawn fertiliser like the PlantCraft Broadcast Spreader. It has an adjustable flow rate that ensures an even spread. 

Defending Against Common Lawn Pests

• When fighting pests like Lawn Grub, Fall Army worm, and Cutworm, an ounce of prevention is worth a pound of cure. Apply a granular acelepryn based product in early spring and early Autumn for year round protection.   

Back yard before army worms:

And after...

5. Replant the Right Grass. 

Choosing the right grass type for your climate is essential. Cool-season grasses like bentgrass are fantastic if you live in temperate or arid regions like the Blue Mountains, Tasmania, Perth or even Alice Springs. 

But, maintenance can be challenging due to their shallow roots and sensitivity to heat, leading to yellowing in the summer. Cool-season grasses grow very slowly in the spring and require more fertiliser and water than other grass varieties.

If you live in a hotter or semi-tropical climate, consider replanting with warm-season grasses that have drought and heat tolerance. 

If your lawn grass tends to yellow during the hottest time of the year, then what works for you might be grasses known for their hardiness and drought tolerance. Tough, warm-season grasses like Kikuyu are more drought-resistant and suitable for regions with hot and humid climates. This is thanks to its large stolons, which give it an intense base. 

Buffalo grass is also a great choice for warm and humid climates. It uses rhizomes (underground stems) rather than stolons to spread. These rhizomes help it access deeper soil moisture, making it heat and drought-tolerant while maintaining a dense lawn. Kikuyu appreciates heat and can tolerate drought of 4 to 5 months maximum without browning or yellowing. It also tends to exceed its tolerance limit and brown off at the peak of the summer but it's one of the best for tropical climates. 

Can you overseed without starting over?

If you don't want to rip up your lawn and start again, you can overseed or plant runners of a more suitable grass type. To help the new variety take over, mow at a height that favors the new grass, water and fertilize according to its needs. Then use specific sprays to suppress the existing grass while encouraging the new one to establish itself.

For instance, if transitioning from cool-season to warm-season grass, use a herbicide like Celsius WG or Fusilade II, which targets cool-season grasses without harming Kikuyu or Couch grass. You can also use a pre-emergent herbicide like Pendulum 2G to prevent weeds from establishing while the new grass is taking over.

Proactive Lawn Care Tips and Checklists

Spring

Prepare for Growth

✔ Rake to remove debris and thatch

✔ Aerate compacted soil

✔ Apply pre-emergent weed control

✔ Fertilize with a balanced fertiliser

✔ Reseed bare spots

✔ Check and repair the irrigation system

Summer

Maintain Health

✔ Water deeply and less frequently (early morning)

✔ Mow regularly, keeping grass at the recommended height

✔ Apply pest control if necessary

✔ Avoid heavy fertilisation to prevent burning

✔ Monitor for signs of drought stress

Autumn

Prepare for Dormancy

✔ Aerate the lawn if not done in spring

✔ Apply fertiliser high in potassium

✔ Overseed to repair any damage

✔ Keep mowing until the grass stops growing

✔ Rake leaves regularly to prevent suffocating the grass

Winter

Protect and Plan

✔ Avoid heavy traffic on dormant grass

✔ Clear any debris that could damage the lawn

✔ Maintain equipment (sharpen mower blades, service equipment)

✔ Plan and schedule lawn care services or purchases for spring

FAQs 

1. Will my lawn come back after turning yellow?

How soon your lawn recovers its natural colour depends on the cause of yellowing. But yellow lawn grasses will green up again as soon as the heatwave is over or they've recovered from nutrient overdoses, the mowing shock or start getting required water. 

2. Why does my grass turn yellow so fast?

Nutrient deficiencies or harmful herbicides are the quickest agents for lawn grass yellowing. Lack of nutrients like nitrogen can rapidly lead to noticeable yellowing because it directly impacts the grass's ability to produce chlorophyll.

3. What season does grass turn yellow?

Cool-season grasses like fescue and Kentucky bluegrass tend to go dormant or yellow during the hot, dry summers with a lot of sun. Meanwhile, warm-season grasses (like Couch and Kikuyu) go dormant in the winter, as they are more suited to warmer temperatures and struggle in cooler conditions.   

 

Conclusion

Yellow turfgrass or lawns usually indicate incorrect care, stressful climatic conditions or disease. Nutrient deficiencies, particularly nitrogen, usually cause yellowing the fastest. Regular care, including proper watering, fertilisation, and mowing, helps maintain a healthy lawn. You need a comprehensive approach with a combination of solutions for effective management. These include aeration, fertilisation, ensuring proper and cleaner mowing, and property watering. 

If you are following good lawn care practices and your cool season grass goes a bit yellow in summer or your warm season grass loses its vibrancy in winter, don't stress! It'll be back when the season changes. Kick your feet up, enjoy a break from the frequent mowing and trust the process.