Abstract: A growing chamber adapted to grow at least a portion of a plurality of plants therein, an inlet duct leading into the growing chamber, an outlet duct leading out from the growing chamber, the growing chamber being sealed from its surroundings except for the inlet and the outlet. A method of growing at least a portion of the plants in the growing chamber, can include: raising the relative humidity level in the growing chamber to at least 45%, lowering the relative humidity level in the growing chamber to below 45%, and repeating the steps of raising and lowering at least five times during a single day.

Abstract: A method of growing plants in which the plants extend in a growing chamber can include emitting light from a light source onto a foliage of the plants, the light source being positioned within a light source conduit having an inlet and an outlet, and the emitted light being transmitted across a transparent wall of the light source conduit to the plants, circulating air in the light source conduit, the air circulating in the light source conduit absorbing heat from the light source, and transferring at least some of the heated air obtained from the outlet of the conduit to the growing chamber, thereby conditioning the temperature in the growing chamber. Other methods of handling the air medium are also presented.