Preventing Crabgrass 101
The first step to preventing and controlling crabgrass is to understand how crabgrass works and when crabgrass grows. Between late summer and early fall, each crabgrass plant produces thousands of seeds. The first frost of the year quickly kills the plants; however the seeds remain dormant through the winter. When the ground warms in the spring, the seeds begin to grow into the unruly plants—and the cycle begins again. The key to controlling crabgrass is ensuring the seeds can’t germinate and produce more plants. There are many ways that you can do this, but the main things to remember when it comes to crabgrass are:
- Kill the plant before it comes up with a pre-emergent herbicide
- Kill the plant after it comes up with a post-emergent herbicide
- Keep it from returning by growing a healthy lawn.
Preventing Crabgrass Before It Grows
If your lawn has a history of crabgrass presence, regular lawn maintenance alone is probably not enough. Pure Green uses the first two rounds of a lawn care package to focus on crabgrass prevention through pre-emergent herbicides. This treatment kills the crabgrass seedlings as they germinate.
Timing is everything when it comes to herbicides. Generally, application takes place when the ground temperature rises above 60 degrees. If you have a newly seeded lawn, you’ll need to wait until you’ve mowed the lawn about 3 times before applying the herbicide to avoid killing your new grass. Further, once herbicide is applied, it is important to wait two to four months to re-seed the lawn.
Fortunately, when Pure Green is handling your lawn care, we have your lawn on the best cycle for its success, so you won’t have to worry about timing things just right.
Killing Crabgrass After It Grows
Once crabgrass seeds have sprouted, a pre-emergent won’t work. You’ll need to resort to post-emergent herbicide control. Because these herbicides aren’t 100% selective, the amount of post-emergent you can safely apply to your lawn depends on the type of grass you have.
Again, timing is crucial for post-emergent herbicides as well. Some things you’ll want to monitor:
- Weather – Apply the herbicide on a sunny, calm day; immediate rainfall will wash away your hard work.
- Time of day – The best time of day to apply herbicide is after the morning dew has dried. However, if you wait until too late in the afternoon, the night dew may prevent maximum absorption.
- Temperature – It is best to apply post-emergent herbicide when you’ll have a few days of guaranteed temperatures in the 60-90-degree range. The warm weather conditions allow the plants to absorb the herbicide quickly.
- Ground moisture – While you don’t want the lawn wet with dew, it is important to make sure that the soil is moist before application. If not, watering the area extensively the day before treatment will help. If it’s extremely dry, water again 2 days after the treatment, once it has had time to absorb.
- Pop-up crabgrass – If any crabgrass plants germinate after the initial application, they’ll need to be treated with a spot treatment.
Maintenance to Prevent Future Crabgrass Problems
Once your lawn is clear of crabgrass, the best defense against the weed in the future is a healthy lawn. Basic lawn care maintenance can keep crabgrass from becoming a problem in your yard.
Things such as:
- Mowing at frequent intervals to keep grass at a consistent length. Keeping your lawn as thick and long as possible creates shade near the soil, making it impossible for crabgrass to germinate.
- Watering in long, heavy intervals rather than shallow, frequent ones. An irregular watering schedule (only when needed) promotes deeper root growth, resulting in healthier grass.
- Fertilizing on a consistent schedule, yearly.
Crabgrass is a nuisance, but preventable in your lawn with a little TLC. Timing and other variables are important to note, so if you don’t see yourself having the time or patience to keep up with it, then it’s time to give Pure Green a call. We maintain your lawn so the only thing you have to think about is how you’re going to enjoy the fruits of our labor.