Intensive cultivation

Intensive cultivation apparatus comprising a chamber having an air vent and a water drainage outlet, a plurality of spray means in the roof of the chamber, a reservoir for supplying water to the spray means, a thermostatically controlled heater arranged to heat the water supplied to the spray means, a plurality of valves regulating the supply of water from the reservoir to the respective spray means, a plurality of valve actuating mechanisms operatively associated with the respective valves, a timing device operatively connected to the actuating mechanisms to open the valves sequentially for a predetermined length of time at predetermined intervals, and a plurality of open-topped removable boxes in the chamber below the respective spray means, each of said valves comprising a tubular valve-seat, a guide rod extending longitudinally through the tubular valve-seat, a valve closure member mounted on the rod and cooperating with the upper end of the valve-seat in order to open and close the valve, a spring connecting the rod to the respective said actuating mechanism, a collar rigid with the valve-seat and guiding the rod, and a stop mounted on the rod below the collar to limit the upward travel of the rod when the valve is opened by the respective actuating mechanism.