If you dislike the appearance of crabgrass in your garden or lawn, consider using a horticultural vinegar product to combat the invasion. "Crabgrass (Digitaria spp.)" can be any of about 27 species of tenacious weedy grass found in the continental United States. Crabgrass can be either an annual or a perennial that grows primarily in warmer climate zones.

Certain chemical herbicides, such as glyphosate, can kill crabgrass, but if you are concerned about using chemical products, a more natural alternative exists. Your crabgrass problem might be solved by using vinegar as an herbicide.

The higher the acetic acid concentration, the more effective the vinegar is in killing crabgrass and other weeds. Culinary vinegar has only five percent acidity, which might be strong enough for some weed-killing purposes, but for crabgrass you should use a stronger horticultural vinegar. Look for a horticultural vinegar with an acidity of 10 to 20 percent.

Mixing a Horticultural Vinegar Spray

Use typical mixing ratios as used with other liquid herbicides in lawns:

  • If you have a small number of crabgrass plants, mix one quart of horticultural vinegar with three quarts of water in order to treat 250 square feet of lawn.
  • For a large number of plants, mix one quart of horticultural vinegar with one quart of water in order to treat 100 square feet of lawn.

Applying Horticultural Vinegar

  1. Spray horticultural vinegar on a warm, sunny, windless day to maximize the vinegar's effectiveness. Keep an eye on the weather forecast and avoid spraying when rain or wind is predicted within 24 hours after you spray. Wait at least 24 hours after rain before you spray.
  2. Pour the appropriate amounts of vinegar and water into a spray bottle or hand sprayer.
  3. Spray all visible crabgrass, soaking it thoroughly, but being careful to keep the spray from other plants.
  4. Pull crabgrass plants from their roots after they

    wilt and die. Leaving the plants in place can result in them re-rooting and continuing to grow. Dispose of dead plants in your community's green waste recycling center; do not add to your compost.