Sorry, but one of the only sure fire ways is to use a conventional product. My family owns a pest control company, and if there were any natural methoods that actually worked, we would sell those instead! I suggest if you don't want to use a pest professional (which costs a lot more than treating it yourself) get some Amdro (a granular bait you can purchase at Wal-mart, Home Depot, Lowes, etc). Ants gone - simple as that. You will not be putting poison in the ground. You are simply treating the mounds. If your concern is your little one eating hands full of product, the alternative is hand full of earth with ants in it! Always follow product labels and consult your pediatrician. Amdro is pet-safe also when used properly. Check with your vet if you have any questions.