There are many reasons why your grass is growing in clumps: grass type, weeds, soil quality, and improper watering and mowing. Knowing why you have clumping, uneven grass is the first step toward fixing it.
What causes clumping grass?
Grass type
While many types of turfgrass have a spreading growth habit, some have a bunch-type (clumping) growth habit. Bunch-type turfgrasses grow in clumps, which stand out if your lawn is thinning.
The common lawn grasses that have a bunch-type growth habit are cool-season grasses, but some warm-season grasses also grow in bunches. These grasses are:
- Fine fescue (except for creeping red fescue)
- Perennial ryegrass
- Tall fescue
- Bentgrasses (can be considered weeds by some)
- Bermudagrass
- Zoysiagrass
If you mixed a bunch-type and a spreading grass on your lawn, you may see clumps of turf that can be a little distracting.
Weeds
If you see strange clumps of grass in your lawn, then you may actually be looking at grassy weeds rather than turfgrass. A common culprit – especially in hotter areas – is crabgrass, which grows in low clumps. In cooler climates, you will likely find bentgrass to be the cause instead.
Here are some weedy grasses that form clumps:
- Crabgrass
- Orchardgrass
- Yellow nutsedge (nutgrass)
- Onion grass (wild onion or wild garlic)
You’ll need to kill these weeds with post-emergent herbicides. Then, apply pre-emergent herbicides in spring and fall to prevent them from coming back.
Bad soil quality
Poor soil can lead to poor grass growth. Many things can go wrong with your soil: soil type, pH level, and compaction. You can check your soil’s quality by conducting a soil test. Let’s go over the conditions that can lead to grass clumps.
Soil type
If you have sandy soil, you’ll be more likely to get clumpy grass on your lawn.
You may also see your grass growing in clumps if you have clay soil. This type of soil has finer particles that can be difficult for water to penetrate, especially if the soil gets compacted. Uneven watering will result in grass clumps; we’ll discuss that below.
Improper pH level
Your soil can be overly acidic or too alkaline, neither of which is good for your grass as it can result in nutrient deficiencies. Grass grows best in soil with a pH level of 6.0 to 7.0.
You can solve the first two issues using soil amendments to improve soil texture and change soil pH. One soil amendment you might be familiar with is agricultural lime, which fixes acidic soil.
Soil compaction
Compacted soil makes it difficult for nutrients, air, and water to get into the soil to your turf’s root system. It can also cause water to pool on your lawn, which can cause grass to grow unevenly in clumps. In fact, pooling water is one of the signs of soil compaction.
To fix soil compaction, you’ll need to aerate your lawn. To learn more, here are some other lawn aeration articles you might find helpful:
- Benefits of Aerating Your Lawn
- Core Aeration vs. Spike Aeration
- How to Aerate a Lawn by Hand
- When to Aerate Your Lawn
Improper mowing
Mowing is a stressful procedure for grass and can be even more stressful when done improperly. Turf stress leads to poor growth, which can include clumping.
If you cut your grass too low or take off too much at a time (lawn scalping), your grass will get more stressed than usual. Grass that’s been scalped can grow in clumps. Always remember the one-third rule of mowing your lawn: Don’t mow off more than one-third of your turf’s height at a time.
Additionally, you should mow when your grass is dry. Mowing wet grass results in clumps of grass clippings, which can smother your grass and lead to a patchy lawn. Weeds can quickly take over these bare patches, which can make your grass look like it’s growing in clumps. Mowing wet grass doesn’t cause it to grow back in clumps.
If you’d like to learn more about how to mow your lawn, check out these articles:
- How to Mow a Lawn the Right Way
- Lawn Mowing Tips and Tricks
- When is the Best Time to Mow Your Lawn?
- When Not to Mow Your Lawn
Uneven watering
When some parts of your lawn get more water than others, those parts will end up growing faster which can lead to a clumpy look.
Overwatering can also cause your lawn to become weaker, making it more prone to diseases and weeds that can also lead to clumps of grass.
You’ll want to water deeply and infrequently to promote a strong root system and even growth. Here are some articles that can help you:
- How Often Should I Water My Lawn with a Sprinkler System
- How Long Should You Water Your Lawn?
- When and “How to Water Your Lawn”
FAQs about clumping grass
How do you fix grass growing in clumps?
To fix clumpy grass, first fix the underlying problem causing it to grow that way. Then, you can overseed your lawn or lay sod to fill in your patchy yard. After that, make sure to practice proper lawn care by mowing, watering, and fertilizing.
Why does my grass pull up in clumps?
If you can pull up your grass in clumps, something is seriously wrong with it – usually with its root system. Here are some reasons why your grass might be coming up in clumps:
- Lawn pests that eat grass roots, such as white grubs
- Fungal diseases, which can rot grass
- Poor lawn care practices
It’s important to address these issues before they get worse, or else you’ll end up with large patches of diseased or dead grass.
Why is my grass growing unevenly?
Improper fertilization and uneven watering are the two most common reasons why your grass is growing unevenly. Grass growing under shade will also grow slower than grass receiving full sun.
Let a pro do the lawn care for you
Preventing grass from growing in clumps typically means staying on top of lawn management. Even if the only thing wrong is the type of grass you’re growing, a lawn care professional can help – from simple mowing and weed control to overseeding and full lawn renovation.
Lawn Love can connect you with pros in your area who can do all that and more with just a few clicks. Hire a local lawn care professional through Lawn Love today.
Main Photo Credit: theilr | Flickr | CC BY-SA 2.0
