In the weed world, crabgrass is the dark overlord. It preys on weak lawns, spreads rapidly, and knits itself into your turf, making it difficult to remove by hand. Even the name – crabgrass – evokes images of ugly, creeping creatures.
But you don’t have to surrender your lawn to this menace. Ideally, you’ll spot it when it first emerges and is easier to kill. Even when it’s mature, however, it can be eradicated with herbicides and, sometimes, good old-fashioned brute force.
In this guide, I’ll show you six effective methods for removing crabgrass. And if you’d rather skip the hassle, LawnLove can connect you with a local weed control pro to handle the hard work for you.
What is crabgrass?
Crabgrass is a fast-growing summer weed that grows in hot, sunny weather. Its thick, rough stems spread low to the ground, rooting where they touch, resembling crab legs. Crabgrass sprouts in spring, grows through summer, and dies with the first frost. You’re most likely to see it in dry, compacted, or underwatered soil, especially if you scalp your lawn.
Method 1: Post-emergent herbicides
We list this first for a reason: Herbicides are the most effective method for getting rid of mature crabgrass.
Post-emergent herbicides kill crabgrass after it sprouts and are most effective in warm, sunny weather, when the weed is actively growing. Early summer is also good; just avoid applying during extreme heat.
There are two main types of post-emergent herbicides:
- Selective herbicides: These target crabgrass without harming your lawn.
- Non-selective herbicides: These kill any plant they touch, including your grass.
Herbicides come in liquid or granular forms. Liquid herbicides are mixed with water and applied to the crabgrass using a common lawn sprayer. Granular herbicides are applied with a spreader to damp grass so the pellets stick.
Erin Hill, weed science diagnostician at the Michigan State University Extension, notes that one active ingredient stands out: “For residential users, there is one main herbicide active ingredient that is effective at controlling crabgrass, quinclorac.” She adds that you’ll find it in brands such as Roundup for Lawns, Ortho Weed B Gon plus Crabgrass Control, and Trimec Crabgrass plus Lawn Weed Killer, among others.
Tips for applying:
- Don’t apply during extreme heat (above 85 degrees): Hot temperatures can stress your lawn and reduce how well the herbicide works.
- Keep your lawn dry after applying: Whether you’re using a liquid or granular herbicide, avoid watering or rain for at least 24 hours to give the product time to absorb fully.
- Hold off on mowing: Don’t mow the lawn 1 or 2 days before and after applying. This gives the herbicide more leaf surface to stick to and increases its effectiveness.
- Always read the label: Each product is different. Some are only safe for certain grass types, and others might need a second application.
- For liquid herbicides: Mix carefully and follow the manufacturer’s instructions.
- For granular herbicides: Apply to wet grass so the granules stick to the weeds.
For widespread crabgrass, use a broadcast treatment across the lawn. For smaller patches, spot treatment is best and minimizes chemical use.
Read more: How to Apply Post-Emergent Herbicides
Method 2: Manual removal
It’s certainly possible to remove crabgrass by hand, but it becomes increasingly difficult the longer you wait. As crabgrass matures, it develops multiple spreading stems that root at various points, creating a web-like network that’s nearly impossible to remove completely by hand. Missing even small root fragments often means the plant will regrow.
By mid to late summer, established crabgrass forms thick mats that can cover several square feet, making complete removal extremely labor-intensive.
So the key is to get it when it’s young. Early in the season when crabgrass plants are small, hand pulling can be somewhat effective, especially if the soil is moist from rain or irrigation. The shallow root system of young crabgrass makes it easier to extract completely compared to deep-rooted weeds like dandelions.
Best tools for manual removal:
| Tool | Characteristics | Cost |
| Hand weeder | Looks like a screwdriver with a notched or forked end. | $15 |
| Hori hori knife | A sharp garden knife with measurement marks on the blade. | $26 |
| Stand-up weed puller | Long-handled tool with claws or spikes at the base. | $30 |
| Garden trowel or hand shovel | Small hand shovel, great for digging around roots. | $10 |
To pull crabgrass by hand, start by watering the area or wait until after a rain. Damp soil makes it easier to remove the entire root. Grab the crabgrass near the base and pull. It usually comes out cleanly, but if the roots resist, use a tool to help loosen stubborn spots without snapping the roots.
Method 3: Natural and organic methods
If you object to using chemicals in your yard, there are a couple of natural ways to deal with crabgrass. These methods won’t get rid of large infestations, and they aren’t as effective as herbicides, but they can help control smaller patches without harming the environment.
Corn gluten meal: This byproduct of corn processing is a natural pre-emergent herbicide. It helps suppress crabgrass by inhibiting seed germination.
According to Dr. Aaron Patton, professor of Horticulture at Purdue University, corn gluten meal has shown some effectiveness in reducing crabgrass in Northern states. But results have been inconsistent.
And Hill, at MSU Extension, explains that while early research with corn gluten meal in the 1990s suggested about a 60% reduction in crabgrass emergence, later studies haven’t consistently replicated those results. She also points out that “the rate of corn gluten meal needed to provide a preemergence benefit is often quite high and not realistic for most homeowners.”
Boiling water: Pouring boiling water straight onto crabgrass can kill off the top growth and weaken the roots. It works best on weeds growing in cracks or places where grass isn’t a concern. Hill cautions, however, that plants often resume growth because the growing points remain protected.
Vinegar: When sprayed directly on crabgrass, it can dry out leaves and slow the plant down. It usually takes a few applications to make a real impact, and you’ll need to be careful, as vinegar can damage your grass and garden plants too. Hill notes that while vinegar and similar botanical products may burn foliage, crabgrass typically grows back since the protected growing points are not sufficiently damaged.
Read more:
- Pros and Cons of Homemade Weed Killers
- Does Vinegar Kill Weeds?
- Does Corn Gluten Meal Work on Weeds?
Method 4: Smothering
Just like grass, weeds need sunlight, water, and air to thrive. Smother them, and you deprive them of those things. Simple, effective, but also time-consuming.
Start by mowing the area, then cover the spot using something thick and light-blocking like black plastic, a tarp, layers of cardboard, or even old newspaper. Be sure to weigh the material down or stake it to the ground so it doesn’t blow away. After a few weeks, the crabgrass underneath will start to die off.
Method 5: Solarization
Solarization uses sunlight to basically burn or superheat crabgrass into submission. Think of it like using a magnifying glass to burn a leaf.
Begin by mowing the crabgrass short and watering the area deeply. Moist soil helps trap heat. Then, cover the area tightly with a clear plastic sheet. Seal the edges with soil or rocks to trap heat inside. Over the course of hot weeks, the temperature under the plastic rises enough to kill crabgrass.
Hill cautions that “smothering and the use of solarization may help kill the crabgrass plants present at the time, but it will also kill any desired turfgrass species covered.”
In addition, these approaches do not reliably prevent new crabgrass from sprouting later, since seeds in the soil can germinate once the cover is removed. Hill notes these methods tend to be more effective against perennial weeds that don’t have large seed banks.
Method 6: Innovative removal methods
If you’re looking for something different from the usual weed killers, there are some innovative methods that may interest you. These methods are for those who want to avoid strong chemicals, and while they are not fast-acting herbicides, they can be effective when used correctly and consistently.
Chelated iron herbicides: This is a selective, iron-based herbicide that targets broadleaf weeds and some grasses like crabgrass. It works by delivering a high dose of iron that’s toxic to the weed but safe for most cool-season turf grasses like Kentucky bluegrass and fescue. The crabgrass absorbs the iron quickly, causing it to turn black and dry up.
Sodium Bicarbonate: Also called baking soda, it is used as a home remedy for crabgrass. When applied to the crabgrass leaves, baking soda can dehydrate the plant and damage its cellular structure. However, this method is non-selective; it can harm your grass, too.
If you want to try this method, moisten the area, sprinkle baking soda on the crabgrass, and let the sun do the rest. You may need to repeat after a few days. Just be careful, too much can alter your soil’s pH over time.
Botanical oils: Botanical or plant-based herbicides are made with natural ingredients like clove oil, cinnamon oil, citric acid, or vinegar. According to Dr. Patton, products containing clove oil (eugenol) and medium-length fatty acids may offer some control, but they should be used with care. They are non-selective and can damage your turf.
Keep your lawn weed-free
Crabgrass can be a persistent problem, but with the right methods, you can take control and restore your lawn’s health. However, if you’re feeling overwhelmed or just want quick results, LawnLove can connect you with the right professional in your area. From expert weed control to yard cleanup and even pest control, the pros can help you with your outdoor space season after season.
Sources:
- PhD. Erin Hill. Weed Science Diagnostician Department of Plant, Soil, and Microbial Sciences. Michigan State University Extension. Personal Interview.
- Aaron Patton. Professor of Horticulture at Purdue University Extension. Personal Interview.
- “Crabgrass.” University of California Integrated Pest Management program.
- “Pain in the grass: Crabgrass.” By Erin Hill and Kevin Frank. Michigan State University Extension.
Main Image: Remove crabgrass using a hand tool. Photo Credit: Dennis Oblander / Adobe Stock
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