Our part of San Diego is one giant anthill, it seems. It doesn’t matter how clean we keep the house: once, a whole army-column of ants marched up to our kitchen-sink to suck the moisture from the drain. We have tried hot pepper flakes, oil, vinegar, pepper-oil, orange-peel, chalk, boiling water, and a whole array of poisons to try to keep them out. It was ineffective. Not even the commercial ant poisons worked very well, and anyway I don’t like to have poisons around the baby. The only long-term effective ant solution were the fires last October, which seem to have decimated the ant population, at least temporarily.
But the ants are back now, and we have finally found two safe ways to keep ants out. So here it is, my one housekeeping tip ever (I’m generally a pretty bad housekeeper): Coffee grounds work. So does turmeric. They don’t harm us, they don’t smell bad to us, but to ants, coffee or turmeric is a line they won’t cross. Even if they do cross it (our ants aren’t daunted by poison, so you wouldn’t think that simple turmeric would stop all thousand-and-one of them), then the coffee or turmeric seems to keep the ants from leaving their scent-trails for other ants to follow, so we are faced with only one ant a day, not a six-inch-wide black column of ant-army. Coffee and turmeric work.
Now every door has a yellow or black line in front of it, and I keep extending our defensive perimeter to every other hole the ants discover. Just today, there was another ant assault on the catfood dish, originating from under the bookcase. The war goes on, but I am armed with turmeric.