A natural peppermint-based routine in August can create an invisible scent barrier around doors and windows that spiders are reluctant to cross. Walking into your bedroom in August and spotting a spider on the wall is enough to make people freeze, but a simple weekly peppermint spray can greatly cut the number that ever cross your doorstep. August spider season and why peppermint oil helpsCommon house spiders look for warm, dry shelter and easy food once summer temperatures dip outside. The most well-studied natural spider repellent. Paired with a weekly peppermint or vinegar barrier through August, that should mean fewer spiders indoors as autumn arrives.