A method for installing a water potential detector in a plant stem comprising the steps of: a) providing a water potential detector comprising: - a compartment with an osmoticum therein; - at least one selective barrier for selective transfer of water between the plant tissue and the osmoticum, while blocking transfer of other ingredients within the plant fluid; - a pressure sensor configured for sensing changes in pressure of said osmoticum in said compartment, wherein said water potential detector being configured for measuring water potential through direct contact with plant tissue adjacent to the vascular conduit of said plant stem via said at least one selective barrier; and - optionally, a temperature sensor for measuring the temperature: inside the plant stem, of the sensor, or of the environment, or all; b) forming a bore through the plant stem by drilling therein; c) optionally, smoothening the inner walls of the bore; d) inserting said water potential detector into the optionally smoothened bore while placing a fluid conductive gel in between said at least one selective barrier and the stem tissue of the plant, such that there is no direct contact between said at least one selective barrier and the stem tissue of the plant; e) maintaining the stem tissue in the bore wet throughout the installation process; and f) filling any remaining gaps between said water potential detector and the stem tissue with a fluid conducting material. a) providing a water potential detector comprising: - a compartment with an osmoticum therein; - at least one selective barrier for selective transfer of water between the plant tissue and the osmoticum, while blocking transfer of other ingredients within the plant fluid; - a pressure sensor configured for sensing changes in pressure of said osmoticum in said compartment, wherein said water potential detector being configured for measuring water potential through direct contact with plant tissue adjacent to the vascular conduit of said plant stem via said at least one selective barrier; and - optionally, a temperature sensor for measuring the temperature: inside the plant stem, of the sensor, or of the environment, or all; - a compartment with an osmoticum therein; - at least one selective barrier for selective transfer of water between the plant tissue and the osmoticum, while blocking transfer of other ingredients within the plant fluid; - a pressure sensor configured for sensing changes in pressure of said osmoticum in said compartment, wherein said water potential detector being configured for measuring water potential through direct contact with plant tissue adjacent to the vascular conduit of said plant stem via said at least one selective barrier; and - optionally, a temperature sensor for measuring the temperature: inside the plant stem, of the sensor, or of the environment, or all; b) forming a bore through the plant stem by drilling therein; c) optionally, smoothening the inner walls of the bore; d) inserting said water potential detector into the optionally smoothened bore while placing a fluid conductive gel in between said at least one selective barrier and the stem tissue of the plant, such that there is no direct contact between said at least one selective barrier and the stem tissue of the plant; e) maintaining the stem tissue in the bore wet throughout the installation process; and f) filling any remaining gaps between said water potential detector and the stem tissue with a fluid conducting material. <EOS>