How to Get Rid of Crabgrass

 

Crabgrass is a grassy weed that thrives in high temperatures and areas with full or partial sunlight. Crabgrass is a summer annual which means it only lives for one year and dies. However, crabgrass will grow back the following year because it produces a large amount of seeds. These seeds can remain dormant in the soil for years before germinating, so you will want to use both preventative and post-emergence tactics to keep crabgrass out of your lawn.

Crabgrass Identification

Here at Perfection Lawn Care, we receive many calls from potential customers about crabgrass in their lawn. Before we tell you how to prevent and kill crabgrass, it is important to verify that the weed is crabgrass. There are two types of crabgrass; Smooth and Large. Here are a few characteristics of crabgrass:

  • Young crabgrass is light green and will look lighter than your grass. This is the easiest time to identify it.
  • Leaves of crabgrass are “broader” than the turfgrass surrounding it. Some people confuse crabgrass as a broadleaf weed for this reason.
  • The stems of crabgrass grow out instead of up (like a crab).
  • Each blade of crabgrass has a fold line in the middle.
  • Crabgrass tends to grow faster than your lawn especially during hot and dry conditions.

 If you still are wondering what crabgrass looks like, take a look at the crabgrass images to the left of the text.

Crabgrass Life Cycle

Crabgrass is a summer annual and will re-establish every year until you prevent it or kill it. Different locations throughout the United States will see crabgrass germinate at different times. In the Northern half of the United States, crabgrass typically germinate around early-mid May. Crabgrass will not be seen in lawns until late June or July. Crabgrass will then die off with the first frost. However, in southern parts of the country, Crabgrass will germinate between January and April. If the weather stays warm enough, Crabgrass can overwinter in warmer climates and produce new growth on a second seeding. Many areas in the Southern United States do get cold enough for frost, which will kill crabgrass.

 

How to Prevent Crabgrass

It is easier and cheaper to prevent crabgrass than to kill it after it germinates. However, you only have a small window of time to prevent crabgrass. The timing of when crabgrass preventer should be put down varies on where you live.

What it comes down to, is Growing Degree Days (GDD). Growing Degree days occur when the high of the day is over 32 degrees. Without getting into the scientific reasoning behind growing degree days basically the optimal time to put down crabgrass preventer is when the soil temperature reaches 50-55 degrees. When the crabgrass preventer is applied when the soil temperature is around this temperature, it allows adequate time for the application to be watered in before germination of the crabgrass begins. Below there is a graph provided by Michigan State University that tracked the growing degrees last year.

 

Crabgrass Preventer Options

There are two options for Crabgrass preventer. First, you can apply a granule fertilizer that contains Pendimethalin or Dimension. Applying a fertilizer that contains crabgrass preventative allows you to kill two birds with one stone. You give your lawn nutrients by applying fertilizer and also stop crabgrass from germinating. The product we recommend is Scotts Turf Builder Halts Crabgrass Preventer with Lawn Food. This product contains Nitrogen, Potash, and Sulfur to give nutrients to your lawn. It also contains Pendimethalin which will prevent crabgrass and other annual weeds from germinating.

To apply a granule crabgrass preventative, you will need a spreader. We recommend using the Scotts Turf Builder EdgeGuard Mini Broadcast Spreader. On the bag of the Scotts Turf Builder we recommended above, there are calibration settings telling you what to setting to set this spreader at. This means you will not have to waste any time guessing if on how much product to apply on your lawn! Many people have asked me, “Should I apply crabgrass preventer before or after rain?” When you use granules, the crabgrass preventer should be watered into the soil. Crabgrass preventer typically should be applied before the rain, but you can always water your lawn after the application as well.

Again, you will need the following products to apply a granule crabgrass preventer:

The second crabgrass preventer option is using a liquid crabgrass pre-emergent. We use Dimension 2EW Herbicide. The rate that Dimension 2EW Herbicide is applied at depends on the type of turf you have and how quickly you apply it. We recommend applying Dimension with a Chapin Pro Series 4 Gallon Backpack Sprayer and wearing Nitrile Chemical Resistant Gloves while doing so.

Even though Dimension 2EW Herbicide is a liquid, it will still need to be watered into the lawn. Water your grass right after you apply Dimension 2EW. We recommend ½ inch of watering for the best results.

Again, the following products are needed to apply liquid crabgrass preventer:

 

Post Emergence Crabgrass control

One of the most common questions I am asked is “How do I get rid of crabgrass in the summer?” If you were not able to get pre-emergent products down in time to prevent crabgrass, do not worry.

The only post-emergent herbicide that will kill crabgrass effectively is call Drive XLR8 Crabgrass Killer. Drive XLR8 Crabgrass Killer has the active ingredient of Quinclorac in it. Many of the crabgrass killers you will find in stores like Home Depot have a small amount of Quinclorac. Drive XLR8 Crabgrass Killer has 18.92% of Quinclorac.

If you just spray Drive XLR8 Crabgrass Killer on crabgrass, there is the possibility that it will slide off the plant. A surfactant is needed to help the herbicide stick to the crabgrass. Not all surfactants will work with Drive XLR8 Crabgrass Killer. The surfactant must contain Methylated Seed Oil. Here at Perfection Lawn Care, we use Prime Source Duo Stick. Only a few tablespoons are needed to be mixed with Drive XLR8, but it makes a huge difference!

You will need a sprayer to spray the crabgrass with. If crabgrass has only invaded a very small area, the Chapin 1 Gallon Pump Sprayer will do the job. If you there are large areas and you do not want to be continually filling your tank up, the Chapin Pro Series 4 Gallon Backpack Sprayer is what many professionals use. For very large properties we use the Master MFG Master Gardener Cart Sprayer 9 Gal.

Safety should always be on your mind when you are applying any type of herbicide. Nitrile Chemical Resistant Gloves, a long sleeve shirt, and pants should always be worn when killing crabgrass.

To reiterate, the following things are needed to get rid of crabgrass:

Now you are ready to get rid of Crabgrass the right way! Note: Do not water for at least 24 hours after applying Drive XLR8 for the best results. If the Drive XLR8 does not have time to dry on the crabgrass, it will not be effective.

How To Get Rid of Crabgrass Without Chemicals

Getting rid of crabgrass without chemicals is tough. However, there are a few options you can consider. First, you could use Avenger Weed Killer Concentrate. This is a non-selective post emergence herbicide that is made from oranges and lemons, so it is 100% organic. Visible results have been seen within two hours of spraying weeds. However, this is a non-selective herbicide which means it will kill your grass as well. It is important to remember to only spray the crabgrass and not the grass surrounding it. I recommend buying a separate backpack sprayer to spray this product. If Avenger Weed Killer Concentrate mixes with other herbicides that you have used, there may be problems.

 Secondly, you could remove the crabgrass by hand. This is the quick, but hard way to remove crabgrass. First, identify that what you are pulling is actually crabgrass. Sometimes certain grasses can look like crabgrass when they are fully mature. Secondly, water the lawn for approximataly and hour. Thirdly, get your weed pulling gloves. Pull slowly and firmly and try and pull out the whole root. You will have to be consistent with this process each year because crabgrass will continue to come back each year due to seeds in the soil.

Killing Crabgrass with Baking Soda

Yes, what you heard is true; Baking soda does kill crabgrass. However, chemicals work much better. If you want to try and kill your crabgrass with baking soda, follow the following steps. First, water the area surrounding the crabgrass you want to kill. Secondly, use soap to lightly coat the crabgrass plant. This will help the baking soda stick to the plant. Thirdly, lightly sprinkle baking soda over the crabgrass. Baking soda will kill the desirable grass you want to keep, so make sure you are only sprinkling it on the crabgrass. Finally, wait for it to die and fill in the bare spot with grass seed.