Even experienced gardeners are challenged to accuratly estimate how much moisture their plants are getting without actually measuring. Between rain, sprinkler systems and manual applications it's difficult. Your plants could be parched or drowning. Just add one, or several, of these simple to install and easy to read gauges to solve the problem. Glass tube is 5.5" with big, black, clear markings. Just push the metal spike into the soil or attached to a fence post. This is one of those frill-free garden helpers you'll wonder how you ever managed without.