Take the guesswork out of watering. The moisture meter measures moisture at the root level. Simply insert the probe to root level and read the meter. The meter will tell you if plants are getting too much or too little water, eliminating two major reasons for plant failure. Great for use with vegetables, annuals/biennials, perennials, shrubs (flowering), and shrubs (foliage).No batteries required! The moisture meter measures 10.75 in overall with a 7.5 in probe.