Abstract: A closed enclosure used as greenhouse, cultivation frame or fish pond and improving exploitation conditions, in which a structure covers totally living organisms to be protected or breeded either directly in the ground or in a culture medium placed in a box. At least one removable cover has edges defining at least one central recessed portion through which extends a multitude of holes or slits having dimensions calculated so as to provide a convenient watering in quantity and quality of liquid contained in the recessed portion towards the culture medium.