A potplant water reservoir in the shape of a glass ball is not only beautiful, but fully functional. The water ball will keep your plant watered for days. Simply fill the glass ball up to two thirds full of water through the stem and push the stem into the soil. If the soil is dry, some water will be drawn out. If the soil is moist, no air can be drawn into the water ball and water will not escape. The need to remember when to water your plant has been taken care of.