What is diatomaceous earth?
Diatomaceous earth is a powder derived from fossilized algae (or diatoms). Many people refer to it as Diatomite or D.E. for abbreviation. It is basically pulverized microscopic calcium based particles like shells that dehydrate anything with an exoskeleton. The particles are very sharp on a microscopic level (think glass shards), and work their way into an insect’s hard outer exoskeleton. They pierce it, and cause the fluids to wick out of the insect. So not only is it effective against ants, but in theory works against fleas, dust mites and cockroaches.
Are there safety concerns?
Although this stuff is all natural, it can be harmful if inhaled. The fine powder can be taken into the lungs where they cause the most damage. It isn’t good to get into your eyes or other mucous membranes either. An important disambiguation must be made as well. There are several kinds of D.E., and not all of them are safe. There is a pool grade diatomite used for filtration that is toxic. You will want the food-grade diatomaceous earth because it is a finer powder, which makes it more effective at killing insects, and because your pets can eat it.
How do I use it?
Diatomaceous earth is easy to use. Simply place it across the points where ants are entering, and you will create a barrier. I have dog food the ants go crazy for, so I put a ring of D.E. on a plate, and put the bowl on top of the plate within the ring. This is more effective than using a water moat to keep ants out of food because the food can fall into the water and attract more ants. This usually makes a big mess too. With a dry powder, food may fall into it, but then it’s surrounded by the diatomite so ants can’t eat it anyway. We put it across the doorways once every other week and it does a good job at repelling ants right away. This keeps them out of our kitchen as well. Depending on your situation, you may have to fill some holes with caulking to keep them from coming in through the walls or other places where you can’t apply the powder. Keep in mind that the diatomaceous earth must stay dry or else it won’t work as well.
I hope you can find a way to use diatomaceous earth that works for you. It has many other uses besides pest control, like body health, ringing ears, and water filters. If you want to see a cool time lapse video of diatomaceous earth's effect on insects see the video below.