Measuring Growing Media pH with Metal-probe and Glass Electrode pH Meters

Abstract

Abstract Probe pH meters are marketed by many horticultural suppliers and cost from $5 to $21. A probe pH meter consists of an analog meter attached to one or two metal probes. To measure pH a probe is pushed into moist growing medium, and the indicator needle points to the pH. Despite low cost and seemingly simple operation, probe pH meters have been criticized as being unsuitable for horticultural use (1, 3). I, therefore, evaluated the accuracy of a probe pH meter for measuring growing media pH.