Abstract: The invention provides a method of growing plants (2) in a growth substrate comprising supplying water to the growth substrate into a first conduit (4) directly connected at one end (3) to the growth substrate and through the first conduit into a second conduit (5) connected to the other end of the first conduit characterised in that the second conduit is at least partially filled with air and the water is released from the first conduit into air space in the second conduit and in that the growth substrate is formed of organic polymeric foam. The invention also provides an apparatus for carrying out the method.