The present invention concerns a horticultural growing and support medium comprising a synthetic foam slab permeable to water, said foam slab comprising: (a) A first, growing surface (1), whence plants grow to ambient and (b) An opposite second, draining surface (2), separated from the growing surface by the thickness of the block, wherein, a limited portion only of the second, draining surface is coated with a coating (2B) having a permeability to water substantially lower than the slab material, preferably substantially impervious to water, for controlling the draining and storage of water contained in the slab and characterized in that, the porous slab is made of a synthetic foam having an open porosity.
