Lawn Care

Why is My Grass Turning Yellow: 12 Most Common Reasons


You work hard to ensure that your grass is lush and green, something you and your family can enjoy all year round.

But other times, you may ask yourself, why is my grass turning yellow? Why does it look patchy? And how do I fix it?

We have put together the top reasons why your beautiful green lawn suddenly turns out to be yellow and not as inviting.

Before We Start: Location & What Type of Grass You Have

If you live in an area that gets a lot more sunlight than other parts, this could be one reason why your grass is turning yellow.

The same goes for soil and water availability. If the amount of sunlight or water available for growth isn’t enough for proper growth, your lawn will turn yellow.

This can happen if there’s too much traffic on the property (from people walking through it) or if there’s not enough fertilizer being applied throughout the season.

The type plays a significant role. Why is my St. Augustine grass turning yellow is because you live in a location with a lot of rain that overstresses the roots of this type, so it cannot absorb nitrogen.

Or, for why is my Bermuda grass turning yellow could be related to you living in a hot climate where fungus is common. It comes down to finding the right balance of location and the type you have seeded your lawn with, like new grass, centipede grass, buffalo grass, and fescue.

12 Most Common Reasons Why Your Grass is Turning Yellow

GrassThese are the most widely accepted reasons behind yellow patches in grass gathered together from industry experts and our experience.

Each one will help you prevent unwanted yellow from appearing on your lawn, so you have a lush and aesthetically pleasing place to run, picnic, and enjoy.

1 – Watering Too Much or Too Little

Watering is a delicate balance. You need to water enough to keep your grass healthy, but not so much that your grass is turning yellow.

Too much water will rob the soil of oxygen needed to produce the green you want.
The symptoms of under-watered grass are:

  • dry, brittle leaves with curly edges
  • brown patches in the middle of the lawn with dead patches appearing around their edges
  • and blades turning yellow at their tips as they die back from lack of moisture
2 – Problems with Insects

Insects are one of the most common reasons for yellow patches in grass.

This could be anything from small holes in your blades of grass, from caterpillars to beetle grubs or worms that feed on the roots and kill your grass from underneath the earth. One infestation is all it takes to turn your lawn yellow.

3 – Your Lawn Has a Disease

A lawn disease causes your grass to turn yellow and eventually die. A few different types of conditions can cause this problem, including fungus and mold.

If you see any signs of disease in your lawn, like yellow spots on lawn fungus, it is essential to address the issue as soon as possible to prevent further damage.

4 – Mowing Mistakes (Height & Oil)

grass mowerThere are a few mowing mistakes that answer why is my lawn turning yellow.

The first is mowing too high or low, which will cause your lawn to suffer from stress or a lack of nutrients from oxygen and sunlight.

The other is oil/petrol spills from your machine. When these substances get on your lawn, they drown the roots and kill off your grass.

5 – Fertilization (Too Much & Too Little)

One of the most common reasons for new grass turning yellow is over-fertilization.

If you’re unsure how much fertilizer to apply, it’s best to stick with the directions on the bag for your grass type.

The goal is to keep the nutrients in your soil as balanced as possible:

  • Too much, and the lawn becomes oversaturated with nutrients.
  • Too little, and there are no nutrients for the roots to send out solid blades for oxygen and sunlight.
6 – Lawn Nutrient Deficiency

Nutrient deficiencies occur when your soil lacks essential elements required by plants for proper growth and health.

These primarily include nitrogen, phosphorus, potassium, magnesium, iron, and oxygen. Nitrogen is the most important as this is what directly makes your lawn green, with iron as a close second. Just be sure to apply any nutritional fertilizer or supplements carefully and with balance.

7 – Soil is too Compacted

Soil compaction is a common reason for yellow spots in grass.

It occurs when the soil is repeatedly walked on or driven over by vehicles, especially when it is dry. This pressure destroys that necessary space between the soil for water, oxygen, and other nutrients.

As a result, your grass has essentially cut off its supply chain of ingredients required to grow strong and green.

That is why people say never to drive over the grass on a construction site because it will undoubtedly harm the lawn.

8 – Your Lawn is Dying or Dormant

Your lawn will become dormant during different seasons of the year, depending on your grass type.

This could mean the grass looks yellow and a bit dead, but it will come back once spring arrives. When the temperature rises in late winter or early spring, the grass will start reaping new growth.

Dying grass is different. If your grass is exposed to hot and dry periods for too long, the roots can lose all nutrients and not regrow.

Keep a close eye on outside temperatures and any signs of drought to avoid this from happening.

9 – Too Much Running and Playing on Your Lawn

Your lawn is more susceptible to damage if used too frequently.

Kids tend to spend a lot of time outside, so they mustn’t use the same area over and over again.

For example, if kids like jumping or playing tag on one particular spot in the yard, this could cause permanent damage or yellowing of the grass.

10 – Grassy Weeds or Unwanted Grass Species

Grass that is a variety different from the lawn you want is considered a weed.

If you are cultivating a yard full of Bermuda grass and get patches of dallisgrass or crabgrass, this would be “grassy weeds.”

You’ll have to eliminate these patches and replant the original variety you want to have on your lawn.

11 – Dog Urine is Not Helping

Dog urine can cause yellow spots on your lawn if it sits too long. This is because dogs produce ammonia and other chemicals when they urinate on the grass.

The ammonia may burn the roots of nearby plants, resulting in some yellowing and dead patches on your lawn. If this happens often enough, fungus growths can form around the area where your dog has been urinating—leading to further problems.

12 – Heatwaves

A heatwave can affect your grass by turning it brown during a prolonged high temperature with little relief from a natural rainstorm.

The grass is forced into survival mode until it can receive water and nitrogen-rich soil once again. If too much time passes in this state, the roots die off, and you lose your grass.

Bonus Point: Keep in Mind the Time of Year

Grass sprinklerDifferent times of year affect grass in various ways depending on the type of grass you have planted.

For example, the answer to why is my grass turning yellow in summer has to do with overexposure to sunlight that dries out the blades of the grass, adds stress to the roots, and creates patches of yellow until water, and cooler temps bring relief.

For why is my grass turning yellow in winter? It is the opposite. The temps are too cold, and your grass needs to enter dormancy to survive different layers of frost.

As long as you have a type of grass that welcomes this dormant period, you should be fine when spring rolls back around, and the yellow grass begins to turn green again.

How to Fix Yellow Grass & How to Make Grass Green Again

How to fix yellow spots in grass starts with watering. It may seem obvious, but if your grass is turning yellow and it’s not the summer (meaning it’s not hot), then chances are you’re over-watering.

To ensure that your soil is healthy and not low on nutrients, fertilize it. For example, the best fertilizer for yellow grass will have nitrogen and iron-infused ingredients.

The location of where you live can also affect whether or not your grass turns yellow. If there’s too much shade or pollution nearby, this could stunt growth. Avoid cutting your grass too short (below 3” in general), and be sure to accommodate the needs of your grass by type and season of the year.

Finally, don’t take your dog to the same areas of your lawn every day, so their urine kills off the grass, and make sure your kiddos are using the entire yard and not the same patch over and over again.

Why is My Grass Turning Yellow Over a Drain Field?

A drain field is used when a private septic tank is installed on your property. As long as the tank is buried more than 6 inches below the surface and has no leaks, you should be okay for growing grass.

If you start seeing patches of yellow around where the drain pipes or tank are located, you may have a leak or too shallow soil. The waste that leaks from a septic tank contains bacteria to clean what is inside.

Normally this will be okay for your soil, but like anything in life, too much will drown your grassroots. You need everything in moderation and balance to avoid unwanted yellow spots.

Can We Prevent Yellow Grass?

So back to the original question: can you prevent yellow grass?

The simple answer is yes.

Do these things and you should be growing a lush lawn in no time:

  • Don’t over/under fertilize.
  • Don’t over/underwater your lawn.
  • Avoid over-mowing it below 3”
  • Avoid using too many chemicals on your property – especially herbicides and pesticides
  • If possible, don’t let dog urine sit on top of your lawn
  • Make sure your kids are not sticking to one area
  • Consider seasonal applications of aerators, nutrients, and other benefits according to your location and type of grass

No one wants to deal with grass turning yellow on their beautiful front, side, or backyard lawns.

This is a lot of information, but it’s all important. Hopefully, by understanding some of the causes behind your yellow grass, you can take steps and prevent yellow grass from wreaking havoc on your beautiful lawn.

Keep in mind that not all the reasons are bad and may only be temporary. However, if you have recurring issues with yellow grass, then it is time to investigate what could be causing it to turn.

Take your time and follow this outline of reasons, and you should be back to enjoying your outdoor area sooner than later.

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