Since it's sometimes impossible to tell which issue is to blame, many well-meaning plant parents have accidentally turned into serial plant killers. Fortunately, there's a tool that prevents both root rot and dehydration—and you likely already have it at home. According to Apartment Therapy, paper coffee filters are a houseplant owner's secret weapon. Regular flower pots have holes in the bottom that allow excess water to drain out, but they aren't always effective. Coffee filters can be useful in under-watering situations as well.