Plant Watering Spike Waterers Automatic Watering System for Potted Plants and Plant Watering Stakes. There are two sizes of connectors; The bigger one's diameter is about 1.57 inches and the smaller one's diameter is about 1.18 inches. The ceramic part will water the soil automatically; The water comes out slowly through the ceramic part, when the soil gets dry again, the water will be refilled. Ceramic watering stakes replenish plants so their roots grow deeper and absorb more water. If the soil is loose, the watering speed will be fast, and vice versa, so the watering time of a bottle of water is not fixed, it is affected by the actual conditions.