Thirsty Light $14.95 The Thirsty Light Digital™ featuring Drypoint Technology is a convenient moisture sensor that continuously monitors the moisture level of a potted plant. Thirsty Light™ features a blinking LED which alerts the user when the soil is dry and the plant is thirsty. The speed of the blink intuitively increases as the soil gets dryer, with 5 levels of sensitivity. With the Thirsty Light Digital™, you’ll never have to guess when your plants need watering.