If seeing a line of ants traipsing through your house makes your skin crawl, your first thought is probably about how to kill them. While you may be ready to run to the store and purchase the largest bottle of ant killer you can find, you don't need to bother. A number of ant-killing solutions can be made using products found around your home.
Borax is often found in the home as a laundry booster or multipurpose cleaner. It is also one of the most effective methods of killing ants and is the same chemical that is found in many commercial ant killers. It is also known as sodium tetraborate or boric acid. Since ants are not attracted to the borax itself, it must be mixed to create bait that will attract the ants. You don't want to make the solution too strong or you will kill the ants too quickly. You want the ants to take the food back to the nests so it will kill the entire colony. Mix approximately 1 part borax or boric acid powder with 50 parts food material. This means mixing about 1 tsp. borax with 1 cup food. Bait material can be honey, peanut butter, apple jelly, corn syrup or a similar substance. Place the bait onto bottle caps or pieces of foil around where you've seen the ants. Keep it out of reach of pets and children. If the first bait doesn't work, try again with a different food.
According to the University of California Integrated Pest Management Online, soap products such as window cleaners will kill ants. Many others also recommend mixing household soap with water and spraying it on ants. Two entomologists at Texas A&M University, Charles L. Barr and Bastiaan M. Drees, even did an experiment to test the effectiveness of Dove dishwashing liquid on red imported fire ants. They found that a mixture of 4 tbsp. soap to 1 gallon of water killed 90 percent of the fire ants within 20 minutes and 100 percent of the fire ants within two hours.
Pouring boiling water onto ant nests is a controversial method of killing ants. Some claim it is effective, others do not. According to entomologists Jeffrey Hahn and Phillip Pellitteri, using waters to flood the nests is rarely effective, but they make no mention of using boiling water. Colorado State University Extension entomologist W.S. Cranshaw does not recommend using boiling water because the hazards of handling boiling water are greater than that of handling insecticides, especially since even boiling water is only occasionally effective. It can kill small colonies of ants if their nests are not too deep, but it will not kill large colonies. Others say that adding clove oil, citrus oil or cayenne pepper to the boiling water will make it more effective, but there is no evidence that this works either.
Grits and Malt-o-Meal
Using instant grits or Malt-o-Meal to kill ants are two long-time folk remedies. It was believed that the material would absorb the moisture from the ants' bodies after it is eaten, which would then kill them. While numerous sources have claimed these are effective, especially for killing fire ants, scientific studies have shown otherwise. Texas A& M entomologist Bastiaan M. Drees tested both products and found they were not effective in killing fire ants. Drees also explains that fire ants do not consume solid foods, so it would not be possible for instant grits or Malt-o-Meal to work as believed. Instead, larval ants chew up the solid foods and make it into a liquid that the ants can digest.
Yeast is another folk remedy that people often use to kill ants. According to folk lore, the yeast produces a gas in the ants that they are unable to expel. Eventually, the gas builds up and the ant explodes. There is no evidence that the yeast works in this capacity, but it is recommended by Kingman Area Master Gardeners Victoria Metz and Marjorie Grimes. They recommend mixing 6 tbsp. sugar, 6 tsbp. active dry yeast and 1/2 cup honey or molasses until smooth. Then place the mixture into 10 small lids and place near ant trails. Another recipe suggests mixing 1/2 cup molasses, 1/2 cup peanut butter and 1 packet active dry yeast together.