How to Use Detergent on Lawns

Larry Parr

Detergent, such as laundry detergent or dish soap, is a surfactant, which means it breaks down barriers to water, allowing fertilizers, insecticides, herbicides and other things mixed with a small amount of detergent to cover plants and lawns more thoroughly and penetrate quickly and evenly.

A few drops of your favorite liquid detergent can help spread fertilizer, herbicide or insecticide on your garden or lawn.

Hard soil that is not accepting water can also be softened with a small amount of detergent, allowing water to penetrate more easily. Add a tiny amount of detergent to a sprayer filled with fertilizer, herbicide or insecticide.

  1. Mix the herbicide, insecticide or fertilizer you plan to use on your lawn or garden in a garden sprayer according to the manufacturer's instructions. Keep track of how many gallons of water you add to the sprayer to mix your chemicals.

  2. Add 1/2 tsp. of liquid dish soap or liquid laundry detergent to the sprayer, cap the sprayer and shake it gently to mix the detergent.

  3. Spray your lawn or garden plants (or weeds) as usual with the mix. Spraying is best done in early morning before the hottest part of the day and when there is little wind. Unless the manufacturer says otherwise, spraying should take place when rain is not expected for at least 24 hours.

  4. Wait 24 hours before watering if spraying an herbicide or insecticide. If spraying a fertilizer, water as per the manufacturer's directions.

  5. Tip

    Wear goggles and a breathing mask whenever spraying potentially toxic or dangerous chemicals. The phosphates in most detergents are good for your plants. Because the surfactants in the detergent allow products to penetrate soil and stick to plants more thoroughly, you may find you need less to get the job done.