Get smart with watering and add Self Watering Flowerpot Inserts to outdoor planters. This product is made from high-grade plastic and includes a reservoir and fill tube fitted with aeration and drainage holes. It can hold up to 132 oz. of liquid and, depending on climate and plant types, keep roots watered anywhere from 3 days to 2 weeks at a time. Simply bury the 16"D x 14 1/2"H self-watering insert under potting soil and plants, making sure the fill tube is exposed above the soil line. Your plants know what to do from there - drink and flourish!