Removing food and water sources is an effective method of controlling gnat populations. Fungus gnats, the type most commonly found in homes, thrive in areas where potted plants, gardens and compost are found. A shovel, sand, a small lidded jar, vinegar and dish detergent are tools needed to eliminate gnats. The process of reducing gnat populations may take several weeks, and requires removing excess water from gardens and lawns, covering compost bins and placing traps for gnats inside the home.
Remove excess moisture from gardens
Turn mulch at least twice monthly to reduce trapped moisture. Remove any standing water, and clean features, such as fountains, weekly.
Pour sand over damp areas and houseplants
Pour 1/2 to 1 inch of sand over areas that collect moisture in the garden to eliminate breeding grounds for gnats. Treat houseplants by replacing the top 2 inches of potting soil with sand to eliminate any larvae that may have been deposited in the plants.
Make a trap for adult gnats
To make a trap for gnats, poke holes in the lid of a small jar, then add vinegar and 3 to 5 drops of liquid dish detergent. Place the traps in areas where adult gnats are most noticeable.