Patent ID: 7249440

Claim:
A plant-growing device comprising a container at least partly filled with a particulate substrate and a plant substrate aerator at least partly buried in said particulate substrate the plant substrate aerator comprising a body having a peripheral wall with an inner surface and an outer surface, the body having an upper cylindrical portion and a lower conical portion flaring downwardly from said upper cylindrical portion, the inner surface of the peripheral wall defining an inner cavity of the body, the inner cavity being in gas-exchange relationship with the surroundings of said body through a permeable portion of said peripheral wall, said permeable portion having an increasing permeability towards a lower end of the lower conical portion, the body having an inlet defined in said lower conical portion and adapted to allow a gas to fill the inner cavity, said inlet being connected in fluid communication with at least one fluid passage defined in a bottom portion of the container, the permeable portion of the body being at least partly located below a top surface of the particulate substrate such that at least part of the gas flows from the inner cavity through said permeable portion of the peripheral wall directly into the particulate substrate, wherein said lower conical portion of the body of the plant substrate aerator extends into the particulate substrate, such that amounts of gas supplied to the particulate substrate along the body increases with a depth of the plant substrate aerator in the particulate substrate, and gas convection means for creating a pressure differential between the inner cavity and the particulate substrate to create a convective flux therebetween, and wherein said inner cavity has an outlet at said upper cylindrical portion, said outlet being provided with a flow control device for controlling the exit of gas from the inner cavity through the outlet.