Gardeners have used Borax to kill creeping charlie in lawns for decades. The secret to Borax's effectiveness is its active ingredient, boron. Boron is actually a plant micronutrient found in trace amounts in most soils. When it is present in large amounts, it kills plants. However, you can eradicate creeping charlie and keep your grass alive because it takes a slightly higher amount of boron to kill turf grass than it does to kill creeping Charlie. The solution used in these steps makes enough Borax weed killer to treat 1,000 square feet of your lawn.
Add 1/2 cup of warm water to 1-1/4 cups of Borax in a small plastic container. Stir until the Borax is completely dissolved.
Fill a bucket with 2-1/2 gallons of water. Add the Borax solution. Stir until the Borax is completely dissolved.
Pour the diluted Borax solution into your hose-end sprayer.
Spray the contents of the hose-end sprayer evenly over 1,000 square feet of lawn.
Refill the sprayer and reapply to your lawn. Repeat until all of the diluted Borax solution has been sprayed on the lawn.