Fuente: Wipo "precision agriculture" An example apparatus includes a housing; an electrode array located in the housing, the electrode array comprising two or more electrodes, each comprising a pH-sensitive coating or encapsulation to measure a pH of a growing media; and a controller configured to: generate an electrical current between the two or more electrodes; measure, by a current sensor, the electrical current flow between the two or more electrodes; and output an estimate of pH based on the electrical current flow.