If you have turfgrass anywhere around your home, you have probably struggled with this insidious weed. Crabgrass can disrupt the texture of your lawn, turning an otherwise finely manicured lawn into a mess. Crabgrass can make your lawn look like it is poorly-maintained, or even neglected. If you or your family love to run barefoot in your lawn, it can also disrupt the luxuriously soft carpet of turfgrass on your lawn. Besides looking ugly, crabgrass has rough, even sharp blades that are no fun on bare feet. The only way to beat crabgrass is to battle it head-on. You need to get out in front of it and stay on top of it. Otherwise, your lawn can descend into a messy patchwork of renegade weed grass.
What is Crabgrass
Crabgrass is actually a family of weed grasses. The botanical name is Digitaria. Two types of crabgrass are common in North America. Most crabgrass that homeowners encounter is either large crabgrass (Digitaria sanguinalis) or smooth crabgrass (Digitaria ischaemum). Both of these are virulent weeds that are hard to control once they have spread. They are especially common in unhealthy lawns that are underwatered, insufficiently fertilized, or drain poorly. That’s probably why so many homeowners associate crabgrass with poorly-maintained lawns. But even a well-maintained lawn can be plagued by crabgrass.
The best way to prevent a crabgrass infestation is to get out ahead of it. Crabgrass is a warm-weather weed that flourishes from late spring and through the warm summer months. It germinates, sprouts, and dies in a single season. At the end of the season, crabgrass dies with the first frost. But don’t let the lull you into a fall sense of security. Although the grass itself dies at the end of each season, its seeds do not. Over the summer, while it is flourishing, crabgrass releases thousands of tiny seeds that can blanket your lawn. The seeds remain through the winter. When spring comes, the seeds germinate, and your infestation begins.
Crabgrass will germinate as soon as the soil temperature at 2-3 inches depth reaches 55 to 60 degrees for four or five days in a row. You can purchase a soil thermometer at your local nursery or home-improvement store. However, you can also take a cue from the local plants. When bushes start to bloom and trees start to blossom, any crabgrass seeds on your lawn will also begin to germinate.
Using Pre-Emergent Herbicide
Once crabgrass takes hold in your lawn, your turf is under a full assault. The best way to keep your turfgrass crabgrass-free is to get out ahead of it and kill it before it sprouts. To do that, you will need to apply a pre-emergent herbicide. As its name suggests, pre-emergent herbicide needs to be applied before the target weed, in this case, crabgrass, emerges. That means that by the time you can see the crabgrass, it’s too late.
To time your pre-emergent herbicide treatment, watch the ground temperature. With a soil thermometer, you can monitor for a temperature of 55 degrees or higher. If you don’t have a thermometer, you can look out for blooming plants and blossoming trees. As soon as the first blossoms appear, get out in your lawn and lay down the pre-emergent herbicide.
It is important not to aerate immediately after applying your pre-emergent herbicide. Aerating will disrupt the herbicide barrier and reduce its effectiveness.
Other Ways to Prevent Crabgrass
In addition to treating your lawn with a pre-emergent herbicide, there are good maintenance practices that can keep your lawn crabgrass-free. In general, the healthier your lawn is, the less susceptible it is to crabgrass and other weeds. The goal of maintenance-based weed control is to keep your lawn so healthy and thriving that it outcompetes any weeds. While this is not a fail-proof solution, a thick, healthy lawn will reduce weed growth and make it easier to treat the weeds that do sprout.
One significant factor in weed prevention is the height at which you mow your lawn. In some specialized situations, such as sports venues and golf courses, the turf needs to be mowed short. However, in your residential lawn, you can keep the grass much longer. TifTuf Bermudagrass can be maintained as high as two inches. Keeping your turf higher will increase shade and make it harder for weeds to get the sunlight they need to grow.
Another factor in maintaining a healthy lawn and beating out weeds, including crabgrass, is to encourage deep, vigorous root growth. Root growth is affected by many different maintenance practices. Your root system is what keeps your turf healthy, so every aspect of lawn maintenance will have an impact.
To improve root growth, start by fertilizing your lawn as needed. For TifTuf Bermudagrass, apply 1-2 pounds of fertilizer per 1,000 square feet of turf annually. Split the fertilizer into two equal applications, once in the fall and once in the spring.
Aerating your lawn at least annually is another way to encourage root growth and keep a healthy lawn. The best time to aerate TifTuf Bermudagrass is in late spring when the grass is beginning to thrive. Aerating loosens compacted soil and exposes the roots to sun, water, and nutrients. After aeration is a great time to fertilize, too, since the fertilizer can go straight to the roots. Just make sure not to aerate immediately after applying a pre-emergent herbicide. The herbicide needs a chance to create a barrier that prevents weed growth. Aerating can disrupt the barrier and make it less effective.
Use the Right Turf to Beat Out Crabgrass
One way to help beat out crabgrass is to start with sod that is certified pure from the only best growers. The Turfgrass Group can help you find a turf grower in your area. Crabgrass is an opportunistic weed, and it will pop up in any bare or damaged patches in your turf. TifTuf Bermudagrass grows thick and healthy, even under drought conditions. It also has a higher spring greenup rating than other common bermudagrass cultivars. That means that your turf will be ready to fight off crabgrass and other weeds earlier in the season than other cultivars.
While no turf is a magic bullet against weeds, TifTuf Bermudagrass is the best way to grow a strong, healthy lawn that can withstand weeds. You can learn more about TifTuf Bermudagrass here. You can also take a look at the science behind TifTuf Bermudagrass here.