The invention relates to a method for the cultivation of a number of plants (9), comprising providing a carrier with apertures for said plants (3, 13) and providing a water supply (8), wherein said carrier can be provided on said water supply in a floating manner and wherein a growth medium containing the roots of said plant or the precursor thereof are placed in an air-containing intermediate space (10) in the apertures in said carrier at such a distance from said water supply that said roots of said plant or the precursor thereof are situated at a vertical distance (a) from said water supply, wherein at least two horizontally opposing sides of an upper part of the growth medium are sideways supported along a height (h) by corresponding sides of a removable side support structure (18), removably arranged on top of the carrier.