If you have your own lawn, there is a strong chance that you occasionally need to deal with crabgrass. After all, you want to keep your property looking pristine. Crabgrass is an annual weed that can quickly smother your turfgrass, so there are steps you need to take every year to block and remove crabgrass. In this article I’ll explain how to kill crabgrass naturally without killing your lawn or laying down harmful chemicals.
Why is Crabgrass a Problem in Lawns?
Crabgrass is an annual lawn weed that appears each year. Its seeds germinate in the spring and summer, and even if you successfully blocked and removed crabgrass last year, you could be fighting it again this year.
Crabgrass seeds are incredibly persistent.
In fact, un-germinated crabgrass seeds are able to stay in the soil for as many as 3 years before they sprout!
Germination of crabgrass takes place when the temperature of the soil three inches down gets to between 55°-65°F for five days in a row.
During the growing season, one crabgrass plant is capable of producing as many as 150,000 seeds. This is one reason why crabgrass is one of the most challenging weeds to get under control for many homeowners.
Once you have crabgrass growing on your lawn, you’re sure to see more later on.
Before you know it, you’ll end up with a significant problem, which is why so many people want to know how to kill crabgrass naturally or otherwise.
Why Does My Crabgrass Keep Returning?
Crabgrass is a persistent problem for a number of reasons.
One of them is the fact that its many seeds can stay active in the soil for as many as three years, germinating whenever conditions are right.
Sunshine permeating the soil is essential for this weed to grow.
That’s important to know, because the best defense against Crabgrass is a thick lawn. This creates a canopy of turfgrass which prevents sunlight from reaching the soil, blocking crabgrass from growing.
Crabgrass is infamous for being unsightly. It’s light-colored, grows horizontally, and it will quickly take over your lawn if you allow it to do so.
In winter, when crabgrass dies, it turns an unappealing shade of brown and is even more unattractive.
Steps: How to Kill Crabgrass Naturally
Luckily, there are natural methods for killing crabgrass that won’t destroy your lawn.
Let’s go over some of them below:
The best way to kill crabgrass naturally is to prevent it from growing altogether.
I like to take a two-pronged approach to this.
Step 1: Organic Pre-Emergent
The first is to spread an organic pre-emergent early in the spring which blocks crabgrass from germinating for the first 6 weeks (I use this one from Jonathan Green).
This will give your lawn a head start and allow it to thicken up and prevent sunlight getting to the Crabgrass seeds and seedlings later in the spring.
And Corn Gluten is organic, so it’s safe to put down and then let your kids and pets loose on the lawn right afterward. But remember – pre-emergents only work by blocking germination, so if you apply it after crabgrass has started to grow it won’t do anything.
If you were too late and crabgrass has already started growing in your lawn, try this product instead – it isn’t a natural product, but it works really well as a pre- and post-emergent crabgrass herbicide. The natural option is to put down the corn-gluten and hand-pull the crabgrass that has already started to grow.
Step 2: Create & Support a Thick, Healthy Lawn
If you use a good pre-emergent and maintain a healthy, thick lawn, you won’t have many crabgrass problems at all.
This is because the lawn helps to stop sunlight from permeating the soil, stopping germination of the crabgrass seeds.
In order to boost the health of your lawn:
- Water your lawn deeply but do it less frequently. This will let the soil surface dry out, and this will help to kill crabgrass that is only shallowly rooted.
- Keep your grass tall. Change the settings of your lawnmower to the highest setting of the recommended height range for your specific kind of lawn.
- Think about overseeding and planting new grass seed in the autumn. This will help because the cold of the winter will kill crabgrass seedlings and your grass seedlings won’t have to compete with crabgrass and weed pressure.
- If you have a thin or patchy lawn you plan to repair, each spring you can spread some corn gluten (20 pounds for every area of 1,000 square feet) on the lawn. This will help to stop the crabgrass germination process. It will also break down and create nitrogen that will provide nutrition to established grass.
Pull Crabgrass Early
Try to pull out crabgrass plants as early as you can in the season.
It’s important that you do this before they have the chance to set seed. Make sure to mow your lawn regularly as well. If you have any significant patches of weeds, you can naturally eliminate them by applying a mixture of clove oil and citric acid.
Be careful with this, though, as it will destroy any plant that it comes in contact with, so if you want to kill crabgrass without damaging your lawn, this isn’t the best option.
Prevent Crabgrass Seed Distribution
When you pull or cut crabgrass, put those clippings and plants in a bag and throw them away.
If you want to use them as compost, it’s crucial to remember to first tie up the bag and place it in direct sunlight for between a month and six weeks.
The heat will solarize the crabgrass and kill the seeds within.
Once this period is over, you can use the material as compost.
Solarize Large Patches of Crabgrass
Something else you can do to help kill crabgrass seed is to wait until the sunniest and warmest period of the year, use your lawnmower to cut the plants as short as you can, apply a generous amount of water, and use a sheet of clear plastic to cover the ground.
This process is called solarization, and it’s a good way to kill a large section of grass or weeds.
You must ensure that the plastic isn’t punctured in any way. Leave it on the ground for between a month and six weeks. During this time you’ll answer the same question repeatedly when all your neighbors ask what the heck you’re doing, and the sheet and the ground beneath will heat the ground sufficiently to destroy all the seeds below it.
After this, you can reseed the area with grass seed, or lay sod.
Kick That Crabgrass in the … You Know.
You now have the information you need to prevent crabgrass germination and know how to kill crabgrass naturally.
Once you get ahead of Crabgrass simply maintain a nice thick green lawn, and apply an organic pre-emergent each spring and you’ll be in great shape.
Final Note: If your crabgrass problem is getting out of hand and you aren’t opposed to using chemicals, check out the video at the bottom of this post. It’s a can’t-miss approach.