There are a lot of potentially toxic herbicides that can kill crabgrass, to the point of leaving an ugly bald spot on your lawn. On the other end of the spectrum, there are also a lot of non-chemical methods and folk remedies that provide questionable results. A few do nothing more than make your lawn smell strange, while the crabgrass sits there mocking you.
The truth is that there is a little bit of art in the science of finding the most effective method for killing crabgrass in your lawn. This includes the often backbreaking labor of hand-pulling stubborn patches of crabgrass to burn up your Saturday afternoon.
If you’ve been struggling to kill the crabgrass on your lawn and keep it from coming back, you might want to try one or more of the following things
Non-Chemical Methods For Killing Crabgrass
There are a few homespun remedies and simple non-chemical options for killing a stubborn patch of crabgrass. Some take time and might require you to replant grass seed or sod afterward.
As a plant, crabgrass needs sunlight for photosynthesis. Covering it or smothering it with a solid object for two to four weeks is usually enough to kill a small patch of established crabgrass.
Ideally, you want to stay away from things like loose mulch. Crabgrass can be tenacious enough to push through loose materials before it succumbs to sunlight deprivation.
instead, try to cover the crabgrass with something solid and heavy. This might be a landscaping brick, cinderblock, an old floor tile, plate, or any object to block the weed from getting sunlight.
Then wait patiently for 4 to 6 weeks for the crabgrass to be smothered to death. When the weed is dead, carefully remove it. Make sure to get all of it.
Then rake the ground’s surface where the crabgrass was and reseed with quality turf seed. Laying down a custom cut patch of sod might be even easier than grass seed, and will ensure any lurking vestiges of crabgrass are unable to soak up any sunlight.
Kill Crabgrass with Boiling Water
while it might sound overly simple, pouring boiling water on crabgrass can kill, or at least weaken it. Though the largest area this seems to work for is limited to a 3-foot radius in order to address the root system. You should also note, that boiling water will harm and kill healthy grass and other plants around the crabgrass.
Spray Crabgrass with Vinegar
Vinegar is an all-natural method for killing crabgrass. It can be a great option that won’t cause lasting soil damage. You just need vinegar that has 5% acidity or higher. Then spray it on the crabgrass until it’s drenched.
You will likely need to repeat this process several times over the course of several days to a couple of weeks, or until the crabgrass fully dies back.
Use Organic Herbicidal Soap
There are several types of organic herbicidal soap that have proven effective for killing crabgrass. Most directions call for spraying the patch of crabgrass until it’s thoroughly drenched.
Just be careful as it will harm any grass or other plants it comes into contact with. Once it dies back, you will need to remove the dead crabgrass and reseed it as needed.
Weed Killers That Target Crabgrass
There are some chemical weed killers that are specially formulated to kill crabgrass. This includes Scotts® Spot Weed Control – For Lawns, Syngenta Tenacity Turf Herbicide, and Ortho Weed B Gon Weed Killer.
These chemical herbicides kill crabgrass and a lot of other weeds down to the root. However, this can leave a short-term bald spot on your lawn. Most of them recommend that you don’t plant new grass or lay sod in the treated area for up to a month after application.
So, they are definitely intended for spot applications, and not for treating a lawn with a major crabgrass problem.
Call in a Professional Lawn Care Company
If you have a severe crabgrass or other lawn weed problem, you might need to call in the professionals to assess and treat your lawn. They can let you know what your options are, and how to restore the appearance of your lawn as fast as possible for the given season.
They might also recommend applying a crabgrass preventer to keep invasive crabgrass from coming back. Though most professional lawn care companies will also try to upsell you into contracting their services in the long-term, which may or may not be ideal for your budget and the state of your lawn.
Easy Tips for Preventing Crabgrass
Crabgrass in your lawn is definitely one of those things where an ounce of prevention is worth a pound of cure. This requires a thoughtful and diligent approach that essentially boils down to following lawn care basics to create a healthier, stronger lawn that is more resistant to weeds, as well as other lawn care problems. This includes things like:
Mowing Higher Than Normal
Mowing your lawn a little higher than normal will reduce the available space for weed growth. It also helps your grass to essentially “Out Compete” any weeds that might try to infiltrate your turn on wind-blown seeds.
Pull Weeds Proactively
A casual walk around your lawn with a weed puller in your hands can help you spot weeds before they can establish a strong presence. This is handy in summer, but it is essential in the spring for preventing crabgrass from establishing itself.
So be sure to pull or treat weeds in the spring before any lingering crabgrass from the year before gets a chance to spread. A weeding tool is best, though even a flathead screwdriver will work in a pinch. The goal is to pull the crabgrass out with its root. Any traces of root left in the soil can sprout a new patch of crabgrass from days to weeks in the right conditions.
Overseed Your Lawn
Overseeding your lawn is an important landscaping technique. Here again, increasing the density of growing, healthy grass in your turn helps outcompete crabgrass and other unwanted weeds. It is especially helpful in cool-season lawns.
Aerate Your Lawn Seasonally
Aerating helps to reduce soil compaction. Loose soil helps healthy grass grow vigorously to outcompete weeds. It’s especially helpful when you consider that a lot of weeds like crabgrass can still thrive in compact soil while grass cannot.