How To Kill Crabgrass Naturally

July 16, 2021

Regardless of whether you’re new to gardening or you’ve been doing it for years, you know the enemy of a good garden is weeds. Crabgrass is an annual weed that tends to pop up more frequently in the hotter months as they thrive in temperatures above 80 degrees Fahrenheit.

In this article, we’ll be going over a few tips on how to kill crabgrass naturally using organic products and get back the garden you’ve worked so hard to maintain.

How To Kill Crabgrass Naturally
crabgrass overgrown weed

How can you prevent crabgrass from multiplying?

Prevention is better than cure.

These tricks can help you stop crabgrass dead in its tracks. Use a pre-emergent before things get out of hand.

This might seem obvious, but one of the easiest ways to prevent crabgrass from taking over your garden is to use a preventor or a pre-emergent during the second mowing of the season.

Overseed your lawn early.

Overseeding is as simple as it sounds: Just plant grass seed onto existing turf. The best time to do this is in fall or early spring, so your grass has enough time to grow before crabgrass can pop up in summer.

How does overseeding help control crabgrass?

Thick lawn grass will choke any existing crabgrass without any intervention on your part. It’ll also prevent germination, stopping crabgrass from maturing and wrecking your lawn.

Grow a thick mean lawn to starve crabgrass.

Weeds can’t grow in a lawn that’s thick and dense. Here’s how you can increase the volume of your lawn:

  • Water it once a week. This will send a signal to your plants to grow deeper, stronger root systems. Watering any more than this will weaken your lawn’s roots.
  • Mow your lawn higher than you usually do. 2-3 inches higher will crowd out crabgrass and stunt its growth.
  • Aerate and detach your lawn. You should do this at least once a year, especially if your turf has clay soil in it. This will improve oxygen circulation and promote a healthier, thicker lawn.

If your lawn already has crabgrass all over it…

These are your next line of defense to naturally get rid of crabgrass:

Reduce seed production of crabgrass.

Pull out as much crabgrass seed on bare patches as soon as you see them. You’ll still have to do this even if you used a herbicide as a crabgrass killer to eliminate it completely.

You'll find that this is much harder to do in summer, as the weeds have grown extensively, with their crab-like root system already established, unlike in early spring, where their shoots are still short.

If you’re struggling to pull out the crabgrass, try the following steps:

  • Water the spots with crabgrass for 30 minutes to soften the soil.
  • Use a weeder or a pitchfork to uproot the crabgrass
  • Add organic manure or rooting fertilizer to the area and reseed with good grass seed to regrow the grass.

Once spring hits, mow no higher than three inches. The rationale behind the height limit is crabgrass needs light to germinate. Since taller grass shades the soil, you'll encounter less crabgrass overall.

Bag crabgrass to prevent seed distribution.

Bag up any plants or clippings and discard them immediately. Ensure that they’re not composted or used as mulch as this stage. Alternatively, you can tie them up and leave them in a sunny area for several weeks where the heat will kill the seeds.

Fertilise your garden as first line of attack against crabgrass germination.

Use corn gluten meal in the spring to fertilize your garden. This will prevent the seeds of crabgrass from germinating in the first place.

Solarise your soil to kill crabgrass.

  • Try this on the hottest day possible: Mow your plants as short as possible and water them generously. Proceed to cover the area with a sheet of clear plastic.
  • Seal the edges around it by digging a shallow trench around the plants and covering the plastic's edges with soil.
  • Leave this in place for four to six weeks and watch the plastic heat up the ground, killing the seeds in the process. Once the seeds are dead, you can proceed to reseed the ground with the grass.

Use boiling water as a cheap natural crabgrass killer.

When all else fails, boil it. Pour it over the crabgrass and its roots. If the roots aren’t saturated with boiling water, you might find the crabgrass popping up again.

Chemical Techniques to kill crabgrass naturally

If the techniques mentioned above haven't worked for you, it might be time to use harsher organic substances to kill crabgrass.

Use salt and sugar combo ammo to kill crabgrass.

Salt should only be used in areas where you want nothing else to grow. Apply it liberally to any visible weeds and water it down. If you want to make it more potent, you can always mix it with vinegar.

While sugar can make the soil harmful for plants, making it a good weed-killer, bear in mind that it can attract pests. To avoid this, mix it with equal amounts of spicy cayenne pepper or chili powder. For obvious reasons, don't let it come into contact with any plants you don’t want to kill.

Use baking soda to naturally kill crabgrass

Baking soda is a phytotoxin, so it naturally damages plants even at a low concentration. To prevent it from affecting surrounding healthy plants, we advise you to use it in powder form instead of a solution.

The following steps should serve you well:
• Spray water on the crabgrass and sprinkle baking powder
• Allow it to destroy the weeds over the course of a few days
• Uproot weeds and replant grass to fill in the roots

Use vinegar as an organic crabgrass killer

A general rule of thumb is to use at least 20% vinegar on weed and 30% on tougher weeds (not the standard stuff you’d buy for cooking, opt for the organic version). Instead of applying it directly to your weeds, add it to salt and dish soap in a mixing cup. Mix well and pour on the crabgrass.

Sponging and spot treating crabgrass areas.

This is a chemical technique for killing crabgrass and other perennial grasses in your lawn. Also known as spot treatment, it's more precise than spraying, and it allows you to avoid the good grasses in your lawn.

  • Mow crabgrass for around two weeks to allow weed to grow higher than your lawn.
  • Determine what grass you have and choose a product accordingly. We recommend you use a product with Quinlorac for Bermuda, Tall Fescue, Ryegrass, and Kentucky Bluegrass.
  • Mix a surfactant with roundup herbicide in a bucket
  • Dip a sponge in the Roundup and lace the first 2-3 inches of the crabgrass blades in it
  • Repeat this process two to three times over the next two weeks and allow it to kill the whole weed.
    We hope you’ve enjoyed reading this article!

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