B SEPOR Ceramic Plant Waterer Set of 6 Pack Terracotta Self Watering Spikes - NEW Improved new material different from normal terracotta, strong but still release water enough for soil. Place this device into soil then stick with bottle full of water, that's all With these watering spikes, water slowly sipped to make plants grow greener, healthier, especially for areas there's air almost no humidity. OUTDOOR & INDOOR: Applicable to both outdoor and indoor plants, if only your planter can hold it and will not lean down after placing a bottle full of water.