You may have heard about using Borax to control creeping charlie. You have to use Borax very carefully. Boron, the active ingredient in Borax, is an essential nutrient, needed in minute quantities for healthy plant growth. Amounts even slightly over what is needed are toxic to plants. Borax can be used against creeping charlie because the weed is more sensitive to boron than grass is. Small amounts can kill creeping charlie without permanently harming the lawn. (Grass may brown a bit, but it will grow out of it.)

The problem is, boron does not dissipate or break down like standard weed-killers. If it's applied repeatedly or at too strong a rate, you will end up with an area where you can't grow anything until the boron leaches out. That may take years.

The most you should treat your lawn with borax is once each spring for two years. Here's the formula:

• Dissolve ten ounces of Twenty Mule Team Borax into four ounces of warm water, then dilute it in 2 1/2 gallons of water. This should be sprayed evenly over 1,000 square feet of lawn, no more, no less.

University of Minnesota Extension Home Page

Copyright ©  1998  Regents of the University of Minnesota. All rights reserved.