AHAhahaha, kill them? No just kidding, seriously this WILL work, plant a row of nettles about a foot or 2 away from your garden, trust me, the first time the nettles get the kids...they wont be going back for more. The best part is dont tell the kids that the nettles are there or what they are and do. Wait until the nettles sting them all over their ankles. The pain goes away after about a half hour so you dont need to feel bad hahahahha, and its safe and legal. =) good luck, nettles keep my kids out of stuff.