Crabgrass is a common weed that can quickly take over lawns. Getting rid of crabgrass takes some work, but it can be done through various methods. With persistence and proper timing, you can kill crabgrass and restore your lawn.
Understanding Crabgrass Growth
Before taking steps to kill crabgrass, it’s helpful to understand why it grows so prolifically. Here are some key traits of crabgrass:
- Crabgrass is an annual weed, meaning it germinates from seeds every year. Each crabgrass plant can produce thousands of seeds that spread easily.
- It thrives in summer’s hot temperatures and takes advantage of soil nutrients. Crabgrass goes dormant when temperatures cool in fall.
- The weed grows low to the ground in wide, spreading clusters. It’s adaptable and can root down shallowly or deeply as needed.
- Crabgrass is opportunistic and good at crowding out surrounding grass. It propagates quickly through above-ground stolons and below-ground rhizomes.
Timing Treatments for Maximum Effectiveness
The key to killing crabgrass is timing. Focus efforts in spring as soil warms up to prevent crabgrass from sprouting. Treat again in fall to kill remaining plants that could produce more seeds:
Spring Precautions
- Apply pre-emergent herbicides: These prevent sprouting and work best when applied before crabgrass seeds germinate. Early to mid-spring is ideal timing.
- Aerate and overseed: Helps the lawn thicken up and out-compete crabgrass. Overseeding fills bare spots that crabgrass would otherwise fill.
- Mow high: Set the mower height to 3-4 inches and avoid scalping the lawn. Taller grass shades soil and inhibits crabgrass growth.
Summer Weed Control
- Spot treat with selective herbicides: Post-emergent herbicides formulated for lawns can kill crabgrass without harming the grass. Liquid, granular and gel options are available.
- Pull small patches by hand: This works best for light infestations. Use a sturdy tool to remove all roots and stems.
Fall Crabgrass Prevention
- Apply pre-emergent herbicides: This prevents growth next spring by stopping seeds from sprouting. Early fall application is optimal.
- Overseed: Thickening up the lawn before winter will make it harder for crabgrass to take hold next year.
- Clear debris: Remove all crabgrass clippings so they don’t sprout or replenish the seed base.
Using Herbicides Effectively
Herbicides can be very helpful for gaining control over heavy crabgrass infestations. There are important guidelines to follow:
- Select crabgrass-specific products: Choose selective post-emergent herbicides formulated to kill crabgrass but not the lawn.
- Read labels thoroughly: Not all herbicides are safe for all grass types. Follow specific label directions.
- Control wind drift: Spray on low-wind days to prevent chemicals from spreading onto desired plants.
- Water correctly after application: Watering too soon or too late influences herbicide activation and effectiveness.
- Wear protective equipment: Gloves, goggles, boots and pants reduce exposure when handling chemicals.
- Dispose of products properly: Never pour herbicides down drains or into roadways. Take to hazardous waste recycling.
Natural and Organic Crabgrass Control
For those wishing to avoid herbicides, there are some non-chemical treatment options:
Vinegar
- Spot spray undiluted white or horticultural vinegar: The high acetic acid content will kill crabgrass. Avoid harming wanted grass by isolating treatment areas. Reapply as needed.
- Mow first to avoid spraying desired plants: Vinegar can kill any plants, so only treat the crabgrass and avoid overspray.
Corn Gluten Meal
- Apply in spring before seeds sprout: Prevent emergence of new crabgrass by inhibiting root establishment of seedlings. Rake product into the soil.
- Accept limitations: Corn gluten meal only prevents emergence of new crabgrass. It does not kill existing plants.
Salt Water
- Spray a salt water solution: Use 1 cup salt per 5 gallons of water. Salt draws moisture out of plants. Reapply frequently for best effect.
- Isolate treatment area: Salt water will kill any plants it contacts, so use a spray shield or targeted sprayer.
- Apply on a dry day: The solution needs time to absorb into the plants before rain washes it away.
Physical Removal
- Pull plants by hand: Use a sturdy tool to dig down and remove all stems and roots of small infestations.
- Solarize the lawn: Cover areas with clear plastic for several hot weeks. The heat kills everything under the plastic. Reseed treated areas afterwards.
Best Practices for Long-Term Prevention
Ultimately, creating optimal conditions for the desired lawn grass will help push out crabgrass over time:
- Maintain a thick lawn: Overseed, aerate and fertilize appropriately to fill in thin or bare patches that crabgrass could otherwise take over.
- Mow high: Longer grass shades the ground, improving the lawn’s competitive edge. Remove no more than 1/3 of the blade height when mowing.
- Water thoroughly: Deep soakings encourage deeper grass roots. Avoid frequent, light watering which favors crabgrass.
- Live with some crabgrass: Trying to eliminate every last plant may weaken the lawn. Focus on prevention and accept a few plants.
- Reseed treated areas: Treated areas will be bare of desired grass. Prompt reseeding fills in spaces before crabgrass can return.
- Do routine fall overseeding: Thicken up the lawn before winter dormancy sets in. This prevents thin areas vulnerable to crabgrass next year.
Common Questions and Concerns
Many homeowners have additional questions when trying to control crabgrass. Here are some key points of interest:
Does vinegar permanently kill crabgrass?
Vinegar kills existing plants when sprayed but does not provide permanent control. New seeds can still sprout, and underground roots may resprout. Repeat applications are needed. For long-term control, a pre-emergent herbicide is more effective.
How long does crabgrass live?
Crabgrass is an annual plant. It germinates in spring, grows through summer, produces seeds in fall, then dies with winter frosts. New plants then sprout from seeds the following spring. Controlling crabgrass requires prevention in early spring and fall.
When should crabgrass preventer be applied?
Apply pre-emergent crabgrass preventer about 2-4 weeks before the average last spring frost date for your area. Another application in early fall can help control weeds the following year. Timing prevents seeds from sprouting.
How do I get rid of crabgrass naturally?
Natural options include hand pulling, salt water spraying, vinegar applications, or using corn gluten meal to prevent seed germination. They require repeated applications for best control. Maintaining optimal lawn conditions is also key to avoid bare spots.
Is crabgrass hard to get rid of?
Crabgrass can be stubborn to control because of its fast germination and growth. It takes over quickly, spreading by above ground stolons and underground rhizomes. Using selective herbicides combined with good lawn care provides the most effective control over time. Prevention is easiest in the long run.
Conclusion
Controlling crabgrass requires diligence and multiple control methods used together. Treatments timed in spring, summer and fall provide the best defense against this stubborn annual weed. Use selective herbicides as well as non-chemical options like hand pulling for best effect. Improve your lawn’s health with proper mowing, watering, aerating and fertilizing techniques. A lush, dense lawn is your best asset against weeds like crabgrass trying to invade. With persistence and the right combination of timed treatments, you can knock out crabgrass and enjoy a weed-free lawn once again.