If your grass is growing unevenly, this could be caused by a mower that needs maintenance. It may also be caused by uneven ground, which can be made even worse if your lawn does not have adequate drainage. In many cases, your lawn may appear to grow unevenly because shade is stunting your grass growth in some areas, a new type of grass has invaded your lawn, or weeds are crowding out your grass. Alternatively, your lawn may need to be aerated, fertilized, or replenished with new grass seed so you can return your lawn to a uniform look.
12 Reasons Your Grass is Growing Unevenly
Uneven grass growth can cause your lawn to look messy and patchy. Even worse, it’s usually not clear right away what the problem is. Use the list below to find the source of uneven grass growth and improve it right away.
Your Mower Needs Repair
Uneven grass growth in a healthy lawn can be caused by the tools you’re using to cut the grass. A mower with a dull blade, misadjusted wheel, or a damaged crankshaft can cut grass unevenly. This results in irregular grass growth that gets worse over time.
- A damaged or improperly adjusted mower can result in uneven grass.
- Perform a full mower inspection to find out if it is the source of the problem.
- A fresh mower blade or repaired crankshaft may solve uneven grass overnight.
Before you start looking at your lawn as the reason for uneven grass, inspect your mower. A lawn mower cutting unevenly is often the issue. Whether it’s a broken wheel, a dull blade, or a bent crankshaft, repairing your mower can return your lawn to an even look.
The Ground is Not Level
Lumps, dips, and other uneven portions can make your grass growth look very uneven across your entire lawn. This is because your mower may cut the grass at an angle in these areas, resulting in extremely short grass in one region, while the grass remains taller in another. Over time, grass that is cut too short due to uneven ground can struggle, die, or allow weeds to invade. This makes the problem of uneven grass even worse.
- Low spots in your lawn can cause uneven grass growth or uneven mowing.
- Lay a long, straight board across patches of poor grass to check if they are level.
- If you find uneven soil, use topsoil and a properly filled lawn roller to build up low spots.
Begin by walking carefully across the portions of your lawn with uneven grass growth. If you suspect an area is not level, lay a straight board across it. Look under the board to see the ground dips and swells in areas. If you find uneven spots, our steps for adding topsoil before you lay sod can help.
Poor Drainage is Harming Your Grass
Water collecting in one area of your yard can drown out the grass in some areas, resulting in uneven growth. This is typically caused or worsened by uneven soil. So, leveling your lawn with topsoil can help to fix this problem.
- Areas of your yard that collect water have poor grass growth, which causes your lawn to look uneven.
- Low spots in your lawn can make poor drainage even worse.
- Digging a drainage trench—like a French drain—will help remove excess moisture and improve your grass.
If your lawn is relatively level but it still has soggy or muddy areas, it’s time to dig a drainage trench to correct the problem. Draining excess water away from moist portions of your lawn will improve grass growth and prevent your lawn from having an uneven look.
Your Lawn is Suffering from Disease
Fungal diseases that attack grass often cause poor growth in areas, which results in an uneven lawn. Look closely at the grass blades in uneven areas. Black spots, rust-colored growth, or a powdery residue on grass blades are all signs of fungal infection. Additionally, fungus often causes uneven growth in circular areas, although the circles may overlap to form more complex shapes.
- Grass with a fungal infection often experiences uneven growth.
- Look for spots, powdery residue, and rusty growth on grass blades—these are all symptoms of fungus.
- Spray infected grass with this antifungal lawn treatment.
Spray an antifungal lawn treatment to fight back against grass diseases and restore your lawn. Chemical sprays are highly effective. Additionally, neem oil is a natural plant oil with powerful antifungal properties. Both options can kill off fungus so your grass can grow more evenly.
- Kills insects like ants, fleas, sod webworms, and more on contact.
- Prevents and controls lawn diseases like black spot, brown patch, powdery mildew, rust, and more.
- Rainproof in a matter of hours.
Your Grass is Growing Poorly in Shade
Are the uneven portions of your lawn mostly in areas that get complete or partial shade during the day? Sunlight deficiency can often cause grass to become patchy and uneven. Trees are not the only culprits that shade your lawn. Your home, garage, or even your neighbor’s house may shade your grass and disrupt its growth.
- Shady areas of your lawn often have uneven growth patterns.
- Trees and buildings that cast shade during the afternoon are the biggest cause of uneven grass growth.
- Aerating and fertilizing your lawn can help promote even growth, even in shade.
Unfortunately, it can be hard to correct uneven grass growth caused by too much shade. Some grasses grow much more poorly in shade than in direct sunlight. However, improving the soil quality through aeration and fertilizer can boost grass growth. We’ll cover those processes later in this article.
You Have Different Grass Types in Your Yard
It is common for invasive grasses to take root in your yard. Growing up in Texas, our tall St. Augustine yard was invaded by low-growing Bermuda grass. This resulted in uneven portions of our lawn. Check the uneven areas to see if the grass coloration and blade thickness is different from the healthier parts of your lawn.
- If a new grass type has sprouted in your yard, it can cause an uneven look.
- Check different portions of the lawn to see if the grass has a different color and blade width in separate areas.
- It is best to attack and kill an invasive grass so it does not continue to make your grass look uneven.
If you do have more than one variety of grass growing in your yard, it’s time to pick one and kill the other. Most grass types don’t mix together well, since they may have different colors and mowing heights. If you identify the invasive grass, you can uproot it or attack it with a grass-killing herbicide.
Weeds Have Invaded
Similar to invasive grass, weeds can choke out grass in large portions of your lawn. This results in bare or sparse areas that do not match their surroundings. Look closely for clover, dandelions, and other creeping weeds. They may be stealing water and nutrients from your grass.
- An overgrowth of weeds can cause grass to struggle in certain areas.
- Check areas of poor grass growth for signs of non-grassy weeds.
- Choose a herbicide that is designed to kill weeds but leave your species of grass unharmed.
- Hand-weeding can help reclaim uneven portions of your yard without the use of chemicals.
If you’ve got a weed invasion destroying some of your grass, it’s best to use a grass-safe herbicide to kill off the weeds. Just make sure to consult a lawn care expert at your home and garden store. Some herbicides are harmless to one type of turf grass but deadly to another. If you don’t want to spray any chemicals, you can uproot the weeds with a weeding tool. Then, your grass can recover.
The Soil is Compacted
Soil that is hardened due to time, heat, vehicle traffic, and regular use often forms uneven hard spots. As the soil hardens in these areas, the grass there struggles. This is one of the most common causes of grass that grows well in some areas but barely survives in others.
- Soil naturally becomes harder in some portions of your lawn over time.
- As soil hardens, it restricts grass growth in those areas.
- Use a core aerator to loosen the soil and promote even grass growth.
The best way to repair compacted soil is by renting a core aerator from your local hardware store. Then, crisscross your entire lawn with the aerator to loosen the soil throughout the yard. Your grass will experience a growth boom and even itself out.
Your Lawn Needs Fertilizer
Uneven lawns are frequently caused by soil that lacks essential fertilizer. As the vitamins and minerals leach out of the soil over time, a healthy lawn can become a patchy mess. If you haven’t fertilized your lawn in more than 6 months, this is likely to be a contributing factor to uneven grass growth.
- Lack of soil nutrients often causes patchy grass growth.
- A yard that hasn’t been fertilized in over 6 months is in desperate need of nutrients.
- Apply slow-release nitrogen fertilizer to feed your grass without the risk of lawn damage.
Applying fertilizer is an excellent way to correct poor soil quality. We created our hybrid fertilizer schedule to feed lawns precisely without risking fertilizer burn. So, if you’re new to lawn fertilizer, I recommend giving it a try.
It’s Time to Reseed
Grass plants, like all organisms, naturally die over time. As the grass in your lawn dies off, it can lead to uneven growth. So, if your grass is dying but it hasn’t been stricken by disease or drought, it could be time to replenish your lawn with new seed.
- As grass plants die off naturally, you will see uneven grass growth.
- Reseeding your lawn (or reseeding the uneven patches) can correct this problem.
- Some grasses—such as St. Augustine—cannot be grown from seed. Sod or grass plugs must be used instead.
Reseeding a lawn requires a little bit of technique to ensure your new grass seeds sprout and put down strong roots. Luckily, we created this guide to reseeding bare patches in your lawn. This can revitalize uneven grass in just a few months.
Pets Have Ruined Your Grass
If you have pets that regularly use your yard, it is very likely they are the cause of uneven grass growth. Animal foot traffic and urine quickly kill grass. Plus, the foot traffic from large dogs speeds up soil compaction in frequently used areas. These factors combine to create a patchy lawn.
- Pets ruin areas of grass where they play or relieve themselves.
- If your grass is uneven where your pets use it, this is probably the cause of uneven grass.
- Apply humic acid to areas where pets have urinated to help revive grass.
Restoring a pet-ravaged lawn can seem impossible at first glance. However, we have a guide to fixing a yard destroyed by dogs. Applying lawn treatments and restricting pet access for a brief period can repair uneven lawns.
There’s Something Underground
If uneven grass growth has appeared dramatically during a period of hot, dry weather it may be due to an underground structure. If you have a septic tank in your yard or an area where an old pathway has been overgrown, the soil will be much thinner there. This means it will dry out more quickly in high heat, which will kill off the grass growing above. When this happens, you’ll have a clearly marked area of uneven grass growth.
- A septic tank or layer of concrete under your grass can cause uneven growth.
- As temperatures rise, the thin soil over the underground structure will dry out.
- Thin, dry soil stunts or kills grass.
- Dig 4–6 inches (10–15 cm) into the soil to see if you hit a hard structure that is causing the uneven growth.
To test whether or not something below the soil surface is the problem, use a shovel to dig 6 inches (15 cm) into the uneven area. If you hit a hard surface, then you know that something belowground is causing the problem. Unfortunately, this can be a hard problem to fix, since the underground structure will have to be removed entirely to enable your grass to grow evenly.
Why is Your Grass Uneven?
The most common causes of uneven grass are:
- Your mower is cutting evenly.
- The ground is uneven.
- Excess water is collecting in certain areas.
- Fungus has begun attacking portions of your lawn.
- Shade is stunting some of your grass.
- A second grass type is invading your lawn.
- Weeds are choking out your grass in some areas.
- The soil has become extremely compact in problem areas.
- Your lawn lacks fertilizer.
- Your lawn needs to be refreshed with new grass seed.
- Pet traffic has killed off portions of grass.
- Underground septic tanks or buried concrete are stunting grass growth.
This list may seem daunting at first glance, but our checklist enables you to pinpoint which potential problem is to blame for uneven grass growth. Once you know what the problem is, it’s much easier to take steps to restore your grass.