A system monitors growth characteristics of a plant having a root buried in a prescribed volume of ground using a plurality of electrodes inserted into the ground at a known spacing relative to one another in proximity to the root or root-like structure. When electrical current is applied to some of the electrodes, electrical potential is measured at other ones of the electrodes to construct a representation of electrical impedance across the prescribed volume locating the root or root-like structure. Growth characteristics of the soil and the plant, for example root size, root shape, soil moisture content, and the like, can be identified by locating variations of the electrical impedance.