IDENTIFY THE ANTS.
Use this excellent ant identification key produced by the UC Davis IPM program to determine the type. Behavior and preferred foods vary, and you must know thy enemy.
CHANGE YOUR WAYS.
Whether sweets, fats or water, ants will find what you provide them. Leave no dishes in the sink. Wipe up food-prep surfaces diligently, and dry out sinks and showers after use. Especially in the summer, ants search for water. Look for leaky faucets or hoses that may be creating an ant-watering hole. Pantry items should be kept in impenetrable vessels like cans or jars. Beware the half-bag of Fritos.
CAULK IS CHEAP.
Exclude the invaders by blocking their entrances. Get to know the caulking aisle at your hardware store and keep a supply stocked at home. Latex caulking comes in several colors; it’s also paintable. Silicone caulking which is often clear or white is not paintable. While you’re there, get some door sweeps, door set or weather stripping to seal up cracks around doors and windows. Scrutinize door and window trim, baseboards, vents–think like an ant. Use a flashlight and be thorough. Let them show you the way: follow their trail to its entrance point and caulk it up.
As a last resort, you may need to poison their whole family. Borax is a naturally occurring chemical compound (aka boric acid, aka sodium tetraborate). It’s commonly sold as a laundry booster called 20 Mule Team. Borax is safe for pets and humans, but the micro-crystalline structure is a deadly abrasive in the body of an ant. In 1986, the EPA published this:
“EPA has determined that, because they are of low toxicity and occur naturally, boric acid and its sodium salts should be exempted from the requirement of a tolerance (maximum residue limit) for all raw agricultural commodities.”¹
It’s even used as a food additive in China to make noodles. (But that doesn’t mean you should eat it.) In fact, as with any chemical, long-term consequences may not be understood. DDT seemed like a pretty safe option once, too. If you decide to use borax as an ant poison, here’s a recipe:
Mix about a half-cup of borax with just enough water to make a paste. If your ants are after protein, mix three parts chicken broth to one part borax paste. If your ants are after sugar, swap a cheap fake maple syrup for the chicken broth. Put this bait in a low-sided container like an upturned lid and set it outside your cabin or home next to the ants’ entrances. Because ants lay down a chemical trail to lead them back to food, placing the bait inside will only strengthen the message that there’s food inside–and will encourage more ants to enter. The bait will be consumed by the workers and brought back to the colony.
Depending on the species, a queen can produce a colony of 10s to 100s of thousands of ants. The ants you see represent only a fraction of the foul, writhing nest that exists somewhere nearby. The borax bait as described above works slowly and can thus be clandestinely delivered to the queen.
Within a week, there should be a visible reduction in ant activity. If not, you may need to be more aggressive with your approach. Circle back to step one and redouble your efforts.