How to Get Rid of Crabgrass in Your Lawn
If you suffer from an aggressive infestation of crabgrass, the most effective means to rid yourself of this weed is to use herbicides. But not everyone wants to douse their lawn with herbicide. So we will also cover a few natural ways to combat a crabgrass infestation.
Why Crabgrass is Difficult to Kill
Crabgrass reproduces every year via seeds. Each plant is capable of producing between 100,000 and 150,000 seeds in its lifetime. Once the seeds shed, they will germinate in the soil and spread like wildfire if not controlled.
And unlike other broadleaf weeds, crabgrass maintains a low profile in the lawn. The lower height of the weed makes mowing impractical to cut the plant.
These factors make it a frustrating weed to battle. However, you can kill the invasive weed with a multistep process involving pre and post-emergent herbicides.
Step 1: Prevent Crabgrass With Pre-emergent Herbicide
The most effective way to get rid of crabgrass is to prevent it from becoming established in the first place! Pre-emergent herbicides do just that. They prevent weeds from germinating in your lawn. After application, pre-emergent products act almost like a “force field” against crabgrass seeds.
Its best to use pre-emergent herbicides before spotting crabgrass in your turf. Once crabgrass begins to grow, pre-emergent herbicides will not kill it.
Apply a pre-emergent herbicide or weed and feed in the early spring. A general rule of thumb is to apply a pre-emergent product no later than the third cut of the growing season. The earlier in the spring you use a herbicide, the more time the pre-emergent has to work.
Make two to three applications of herbicide to ensure an adequate protection against crabgrass. Remember to moisten the lawn before application of granular products.
Some products may need watering post-application to activate and spread the pre-emergent herbicide. If you are looking to overseed, wait at least 90 days to apply it after using a pre-emergent. Many pre-emergent products will keep grass seeds from germinating or sod from developing.
Choose The Right Pre-emergent Herbicide
Choose the right Crabgrass pre-emergent herbicide for your lawn. Pre-emergent herbicides prevent undesirable weeds from growing. They are a strong weapon in your war against crabgrass.
Also Use Healthy Lawn Practices
Don't only rely on herbicides to kill or prevent crabgrass. The best way to reduce the crabgrass in your lawn is to keep your ornamental grass as healthy as possible.
A healthy lawn will crowd out crabgrass and help prevent it from growing. Pre-emergent herbicides help kill and prevent crabgrass plants from growing that try to break through.
Aerate your Soil
Aeration reduces soil compaction. This allows the most water and nutrients to seep into the soil. More water and nutrients = a thicker, more healthy lawn.
Overseeding your lawn increases the thickness of your grass. This in turn reduces the opportunity for crabgrass to germinate and grow.
Water Longer, Fewer Times Per Week
To help prevent crabgrass, water longer but less often. Instead of watering your lawn 4 times/week for 15 minutes, consider watering twice per week for 30 minutes. Longer water times ensure water seeps deep into the soil.
Watering fewer times per week means the top layer of soil may dry out before you water again. This is detrimental to shallow-rooted plants like crabgrass.
A higher setting on your mower deck means your lawn will be thicker. A thicker lawn prevents sunlight and nutrients from reaching germinating crabgrass seed.
Remove Dead Crabgrass Plants
When you kill or pull crabgrass in your lawn, be sure to discard of the plant into your garbage can. If you don't, the seeds will fall off into your soil to attempt to germinate the following year.
A single crabgrass plant is capable of producing up to 150,000 seeds. This is the most important reason crabgrass is so difficult to control!
Step 2: Post-Emergent Herbicides
Post-Emergent herbicides kills crabgrass after the weed has already started to grow. After the effectiveness of pre-emergent products fades, post-emergent products should be used.
Apply a post-emergent product at the first signs of weed growth. Post-emergent weed killers interrupts the weed's metabolism processes, killing it to the root.
During the heavy growing season, you can apply multiple applications of post-emergent products. Use Post-emergent products on fresh sod at lower concentrations. Always follow the manufacturer's instructions and application rates when using herbicides.
Kill Crabgrass Without Killing Your Lawn
To protect your lawn, it's important to select the an herbicide that won't kill your grass. For example, if you have a St Augustine lawn, don't buy a crabgrass herbicide that also kills St Augustine.
Choose the Right Crabgrass Herbicide for Your Lawn
Use the table below to select the best post-emergent crabgrass killer that won't kill your grass. Post-emergent herbicides like the ones listed below kill crabgrass that is already growing.
|Grass||Post-emergent Herbicide for Crabgrass|
|Bermuda||Fertilome Weed – Out With Crabgrass Killer RTS|
|St Augustine||Southern Ag Atrazine Weed Killer for St Augustine Grass|
|Zoysia||Fertilome Weed – Out With Crabgrass Killer RTS|
|Fine Fescue||Fertilome Weed – Out With Crabgrass Killer RTS|
|Tall Fescue||Fertilome Weed – Out With Crabgrass Killer RTS|
|Kentucky Bluegrass||Q4 Plus Turf Herbicide|
How to Get Rid of Crabgrass In Summer
To kill crabgrass during the summer, use a two-pronged approach of herbicides and fertilizers. Fertilize your lawn to keep it thick and healthy throughout the summer. Use herbicides like those listed above to kill any crabgrass breakouts you encounter.
Consider watering fewer times per week but for longer periods of time. This keeps your lawn healthy but keeps the top-most layer of soil dry. Keeping the top layer of soil dry is detrimental to shallow-rooted plants like crabgrass.
How to Get Rid of Crabgrass Naturally
There are a couple of natural, herbicide-free ways to kill crabgrass.
1. Use Vinegar
Did you know that vinegar can be an effective weapon against crabgrass? Simply spray vinegar onto the weed until you drench it. Repeat every week until the plant dies.
Vinegar is not as effective as herbicides, which need only a single application. But vinegar can kill crabgrass with diligent application.
2. Use Scalding Hot Water
Heat a pot of water until it is scalding hot. Then, quickly but carefully pour the hot water over the crabgrass. The hot water will “cook” the crabgrass plant and kill it.
3. Pull the Crabgrass Plant By Hand
Use your hands and pull the entire plant up, including the root. Be sure to discard of the plant! This way no seeds will fall into your soil to perpetuate the plant the following year.
Bonus: Recommended Weed & Feed Crabgrass Killer
Scotts Turf Builder and Crabgrass Preventer kills crabgrass and fertilizes your lawns at the same time. It delivers the nitrogen your lawn needs to green up. Also, it contains a pre-emergent herbicide (Pendimethalin) to prevent crabgrass.
After applying, ensure that the lawn receives between .25 and .50 inches of water for best results. You can use Scotts Weed and Feed and Crabgrass Killer on almost all residential lawns. Do not use the product on established or recently seeded lawns.
Do not oversee until at least 60 days after applying Scotts Crabgrass Killer.