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,Characterized in that, 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.
