- Crabgrass grows in bare areas of your lawn and is in constant competition with grass.
- Use a herbicide to remove crabgrass patches before they bloom or remove clumps by hand.
- To prevent further growth, sprinkle grass seed on treated areas immediately after weeding.
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If creeping patches of crabgrass on your otherwise lush lawn are making you cranky, there are a few simple steps you can take to remove common weeds.
You can remove small crabgrass spots with a herbicide or you can pull the weeds out by hand. However, there are times when you should take a whole different route, says Frank S. Rossi, Ph.D., a New York turf extension specialist and associate professor of horticulture at the School of Integrative Plant Science from Cornell University.
Read on to learn how to deal with crabgrass problems, how to recognize when crabgrass has taken over your lawn, and what steps you can take now to promote a beautiful weed-free lawn next spring.
What is crabgrass?
Crabgrass (Digitaria) is an annual weed that grows in low tufts on the ground in bare areas of your lawn. As crabgrass grows, its green, grass-like leaves extend from the center of the plant. The resulting pattern resembles a crustacean, which gives the weed its proper common name.
Crabgrass thrives in a few key seasonal conditions: heat and dry weather. These same two factors hinder the growth of the most desirable healthy lawn grasses that crabgrass often chokes and competes for space with.
The prevalence of heat and dry weather in summer, along with the hardy nature and life cycle of crabgrass compared to lawn grass, help explain why crabgrass is so ubiquitous in many parts of the United States. United in summer. By the time you notice the emergence of crabgrass, it may be too late to save your lawn, at least this year.
âIf your lawn is more than 50% crabgrass, it’s time to replant,â says Rossi. If so, you can help your grasses win the battle for âsurvival of the fittestâ next year by taking some simple preventative steps now.
If your goal is to eliminate a few emerging problem weeds, Rossi says spot treatment will work – as long as you time it correctly.
When to kill crabgrass
Before you learn how to kill crabgrass, you need to know when to kill crabgrass. It is important to do this at some point in the plant’s life cycle.
Crabgrass reproduces from seeds that germinate under specific conditions.
“In most climates of the continental United States, crabgrass is a summer annual, which means when the soil is 50 to 60 degrees Fahrenheit for five to seven days in a row, you’ll have the perfect time. so that it germinates into a seed, âexplains Rossi.
Once crabgrass germinates, it grows rapidly. It is in constant competition with lawn grasses, which typically experience their first significant growth of the season long after crabgrass weeds have started to develop. By the time a crabgrass weed dies in the fall, it will have produced up to 150,000 seeds, which are left in the soil to germinate the following spring.
It’s important to weed strategically in order to interrupt the plant’s life cycle, says Rossi. âIf you only have a few plants, pull them out before they flower. You don’t want to add it to the seed bank, âhe says. When crabgrass flowers you will see large, slender branches with purple tips.
How to prevent crabgrass from growing back
The key to preventing crabgrass after removing problematic spots is to maintain a dense, healthy lawn, explains Rossi. “If you have a lawn and you don’t plant seeds, you might get crabgrass,” Rossi warns. He says you can discourage the future growth of crabgrass by taking the following steps now
- Plant high quality grass seed between mid-August and mid-October to prevent weed growth in spring and summer.
- Apply a nitrogen fertilizer after you’ve planted your lawn to encourage dense, healthy grasses.
- Cover flower beds and vegetable gardens with black landscaping plastic and lay mulch in flower beds to prevent weed growth.
You can remove crabgrass patches by applying a selective crabgrass herbicide, or you can hand pick up weed spots.
In order to plan the most effective treatment, it is important to know where a crabgrass plant is in its annual life cycle. When treating weed spots, apply a herbicide or pull them out before the plant flowers.
A healthy, dense lawn is the key to effective prevention of crabgrass. Plant high quality grass seed from mid-August to mid-October for best results next spring.