Crushed decomposed granite is a natural material used for walks, patios and driveways. Water permeable, it is the surface of choice for both eco- and budget-conscious homeowners. Occasionally, however, grass and weeds sprout in even firmly compacted gravel. While annoying, the grass is easily dealt with if you take quick action using one of several methods.
Things You'll Need
Corn gluten meal product or other pre-emergent herbicide
1 gallon white vinegar
2 ounces orange oil
1 teaspoon dish-washing liquid soap
Lay weed cloth over the compacted soil surface before adding the decomposed granite. Weed cloth prevents grass and weeds from growing in the decomposed granite.
Apply corn gluten meal or a different pre-emergent herbicide. Corn gluten meal is a natural byproduct of milling corn for cornmeal and other products. Apply 20 pounds for every 1,000 square feet of decomposed granite, and sprinkle it with water according to its manufacturer's directions.
Spray the grass with a vinegar solution. Mix 1 gallon of white vinegar with 2 ounces of orange oil and 1 teaspoon of dish-washing liquid soap to make the solution. Thoroughly soak the grass with the mixture.
Spray actively growing grass with a glyphosate product according to its manufacturer's directions. Allow several days for the grass to absorb the glyphosate. The herbicide requires time to reach the roots and kill the entire plant.
Consult the master gardener at your local agricultural Cooperative Extension Service office for information on preventing and killing grasses in your area. Apply herbicides or pull up the grass as soon as you see it sprout. Cut the bottom out of a large coffee can. Place it over the grass, and then spray a glyphosate product into the can and onto the grass. Using that method prevents overspray when you work close to landscaping. Other pre-emergent and herbicide products are available at home improvement stores and gardening centers.
Wear gloves, safety glasses and a breathing mask when applying herbicides, including organic products such as corn meal gluten. Avoid spraying and spreading herbicides on windy days. You may accidentally kill desired plants on the perimeter of the decomposed granite.