Keep your plants from getting too thirsty and - at the same time - recycle your old plastic bottles. An inexpensive and easy way to keep your plants happy. Just fit these adapters into plastic bottles and give a slow, steady flow of water to your favorite plants. A great way to keep your plants watered when you're on vacation and a much easier to take care of them when you're home. Except for cactus and some succulents, most plants prefer a slow, regular watering instead of the extremes of too much and then long dry spells.