DIY Your Own Ant Spray (Without Harming Your Plants)

Ants are a common nuisance for gardeners. While there are some ways in which ants can benefit gardens, such as aerating the soil, overall most people would prefer to not have them around. That is particularly true when it comes to dangerous types of ants, such as fire ants, or when the population gets so large as to be destructive. However, most gardeners would also prefer to prevent ant infestations in an eco-friendly way, without damaging the very plants they are trying to protect. While there are a number of commercially available products that claim to do just that, you can also easily DIY a plant-safe ant spray.

There are actually several ways to do this using ingredients found around the house. But keep in mind that some of these DIY concoctions work as a temporary deterrent, while others function as an insecticide. It is also worth noting that almost all of the natural ant spray formulas are potent short term, and must be reapplied often in order to maintain their effectiveness.

To create a simple DIY insecticide, you'll need boric acid or borax, honey, and water. Mix a teaspoon each of honey and boric acid in a cup of hot water. Stir the mixture well until everything is thoroughly dissolved. It works because boric acid can actually kill ants, and the honey attracts them like bait. Pour the mix into a spray bottle and spray directly onto visible ants and mounds. You can also put this mix, combined with a bit of bread or cracker, into low, flat bait containers — a clean plastic hummus container with a small hole in the side works well — placing them near plants that attract ants to provide continual protection. 

Most natural solutions function as a deterrent or repellent, rather than as an insecticide. They typically do so either by disrupting the ant's ability to follow established pheromone trails or simply because they don't like the scent. While a number of substances work as ant deterrents, some ingredients such as vinegar, can harm your plants. So, when it comes to creating a DIY ant repellent spray for your garden, you need an active ingredient that is plant safe. While there are many options, including lemon juice or diatomaceous earth, One of the best choices for this purpose is actually plant-based — cayenne pepper.

To create an ant repellent from cayenne pepper, all you need is water, dish soap, and ground cayenne pepper or pepper flakes. Mix a few drops of dish soap and a couple tablespoons of cayenne pepper with a gallon of water. If you are using pepper flakes, let them steep in the water for a few hours. Once the mixture is ready, spray it on ant trails and mounds, as well as around the perimeter of your garden. The capsaicin in the pepper prevents ants from finding and following their scent trails, meaning they're unable to find their way back to your garden. While this is an effective deterrent, it needs to be reapplied often, as well as after every rain shower.