A tensiometer is a device used to measure the tension or moisture level in soil. It helps farmers and gardeners determine when to water their plants by providing accurate readings of soil moisture. This information is crucial for maintaining healthy crops and conserving water. Tensiometers typically consist of a sealed tube filled with water and a porous ceramic tip. As the soil dries, water is drawn out of the tube, creating a vacuum that can be measured. This measurement indicates the soil's moisture tension, guiding users on irrigation needs and improving overall plant health.