It can be alarming to see your beautiful green lawn turning yellow. It may happen in patches, in large swaths, or all over your lawn. If you’ve looked out at your yard and asked yourself “Why is my grass turning yellow and dying?” you’re not alone. In today’s article I’ll discuss possible causes and how to fix each one.
The truth is that there are many possible causes behind this color change in your grass.
But don’t panic about it. This is a common occurrence and most of the solutions are quite simple to implement.
With a little care, your yellow, wilting lawn will only be a temporary problem.
Now let’s get your grass back to the deep green carpet you’re after!
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Why is My Grass Turning Yellow and Dying – Causes & Solutions
Here are some of the most common reasons grass turns yellow and starts to die in lawns.
I’ll also share the best way to address each issue.
Improper Fertilizer Applications
Improperly fertilizing your lawn can cause it to turn yellow.
Both over-fertilizing and under-fertilizing can be detrimental to lawns.
Over-fertilization causes chemical burns that lead to grass turning yellow or even dying. As with most plants (and even people!), grass has a preferred pH and any variations outside of that will create problems.
Under-fertilizing can also lead to yellowing grass because of nutrient deficiencies. The most common culprits are iron and nitrogen.
If you notice that your whole lawn is turning yellow, then you most likely have a nitrogen deficiency. By comparison, a lawn that has yellow only in patches is more likely to have an iron deficiency.
Be wary, though, as too much nitrogen is the main cause for chemical burns in the grass, so throwing down more fertilizer may just make the problem worse.
This can easily be avoided by properly using fertilizer. Follow the instructions on the label and use the appropriate fertilizer for the season.
I use and recommend Milorganite. It’s a slow-release, organic Nitrogen fertilizer which contains Iron. It won’t burn your grass, and will help it green up.
Grass has different needs in each season, so fertilizers will use different ratios of nitrogen, phosphorus, and potassium to accommodate. You can even get a soil test kit, which can tell you if there is a specific deficiency (I use this one from Amazon every spring).
It is also key to spread fertilizer evenly. This will help to prevent chemical burns from over-fertilization in spots that get overlapped. It will also help to prevent nutrient deficiencies in areas that are missed.
One way to do this is by systematically going over your lawn with a seed or fertilizer spreader, similar to the pattern that you would use to mow. Be careful at the end of each pass (where you turn). This is where most people drop extra fertilizer accidentally.
For the same reason that over-fertilizing can turn grass yellow, animal urine can also have the same effect.
Urine and even feces contain a lot of nitrogen that can cause chemical burns to your lawn. Urine can also mess with the pH of the soil that your grass is trying to grow in.
Dogs have a habit of doing their business in the same place every day, which can compound the problem.
Thankfully, this can be remedied by taking Fido elsewhere to do their business.
And there are dietary supplements for dogs which can help to make their urine grass-friendly (Amazon link).
Urine spots can be quickly turned green by using a patch and repair seed mixture. An even quicker solution is to replace the patch by installing sod.
Over-Watering Your Lawn
A lawn that gets too much water is not only prone to disease (more on that below), but it can impact root development.
Overwatered grass tends to turn yellow because the waterlogged soil doesn’t allow much oxygen or other nutrients to penetrate to the roots. As a result, roots will not grow deep into the soil, making your lawn vulnerable to damage.
You should only be watering when you notice the top layer of soil is dry.
Watering in the morning is the best time of day, and it is crucial to allow the water to absorb and the blades of grass to dry in the sunshine.
Ideally, most grass can manage with just one inch of water per week. It is better to water your lawn deeply and infrequently.
Some varieties of grass are more drought-resistant and can live on less water.
And remember to take note of the soil in your yard. Grass growing in heavy clay soil will need less water than grass growing in sandy soil.
A yellow lawn quite often indicates a disease.
Usually, lawn diseases are of the fungal variety. This can include fairy rings, dollar spot, snow mold, fusarium, or smut.
In addition to yellow grass, you may see a coating of a white or black powdery substance. These diseases most commonly develop when there is too much moisture. Excess moisture can be due to things likes overwatering, watering too late in the evening, or a thick layer of thatch in your lawn (which prevents water from penetrating the soil and keeps your grass wet instead).
The best way to prevent disease in your lawn is by properly maintaining it.
Aeration may seem like an unnecessary step to most people, but it helps air circulate beneath the soil and prevents your turf from being waterlogged as well. I recommend aerating and/or using a lawn dethatcher once every 2-3 years for most lawns to maintain the health of your lawn. Overseed your lawn and top-dress with compost at the same time for best results.
If you have a recurring disease problem even after following these steps, then you can also choose to apply a fungicide in the spring.
This is a pretty easy and inexpensive process, and should resolve any disease problems in your lawn.
But remember – this treats the problem, not the underlying cause. You’ll want to take steps to make sure the disease doesn’t come back.
Pest Problems in Your Lawn
Sometimes you will need to take a closer look at your lawn to answer the question “Why is my lawn turning yellow and dying?”
Pests that cause yellow grass are more difficult to identify, but if this is the cause it’s important to diagnose the problem correctly.
If the above solutions don’t fix your problem, then you may need to get down and dirty on your lawn.
Look for any tiny bugs, egg sacs, fuzzy or powdery coatings on grass blades, or even holes in the ground that have been created by bugs.
Some insects can turn your grass yellow and cause it to die by feasting on the roots of your grass beneath the soil. They often go undetected since they are more difficult to see.
I recommend digging a 1 foot x 1 foot x 1 foot section of your yellow lawn up so you can look at the turf and soil. You can also check by cutting a “flap” into your lawn to look underneath the grass.
You can replace the turf when you’re finished your investigation, and this will do minimal damage if there aren’t any pests (you’ll be able to lay the grass back down).
Whether you have lawn grubs (this usually presents as brown spots, not yellow), or some other pest, there are ways to treat the underlying problem.
My advice for treating most pest problems is to purchase and apply beneficial nematodes to your lawn.
These small worms will actually seek out and destroy pests in your soil for you, and it’s a natural (and incredibly efficient) way to improve your soil health and fix lawn issues. You can order them online (Amazon link), or may be able to buy some locally.
Your Mower May Need Maintenance
If you notice that your grass tends to turn yellow after mowing your yard, then you might have dull mower blades.
Dull blades damage the blades of grass by not cutting the tips of your grass blades cleanly. This leaves grass more susceptible to disease.
It can also do damage to mow wet grass because your clippings will inevitably clump on the blade and create an uneven cut.
The best way to solve this is to, of course, sharpen or replace your mower blades. You can have your mower blades professionally sharpened, or try to do it yourself, but new blades are not very expensive, and most homeowners feel more comfortable just buying a new pair.
Sharp mower blades will ensure a good quality trim going forward.
To remove yellow grass caused by a previous mow, you can set your mower deck a little bit lower to trim the damaged blades a bit more.
Just be careful not to scalp your lawn by mowing too close to the soil. That can be just as harmful to your grass as a ragged cut. An ideal grass height is about two inches, or a little more.
And if you do change your mower’s blades be careful! These blades are sharper than they look. Use gloves, long sleeves, and wear safety glasses. Also remember to disconnect the spark plug cable before you begin work to avoid risk of shock.
Why is My Grass Turning Yellow and Dying? It Depends.
It’s difficult to say for certain why your grass is turning yellow and dying since I’m not in your yard with you.
But it’s likely that the cause is one of the reasons I’ve listed in this article:
- Improper Fertilization
- Animal Urine
- Lawn Diseases
- Lawn Pests
- Dull Mower Blades
Take your time to diagnose the problem, and then take steps to remedy it based on my recommendations in this article.
Your grass will be back to that healthy green color in no time.
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