The device comprises an annular body (1) which is completely or partially open towards the bottom and is provided with a hole for its connection to a water supply pipe. The body can be surmounted by a casing (1') which is open at the top, the edge of said opening being turned over (1'') towards the inside to collect the water which condenses on the internal walls of the casing (1') and make it drip on the seedling. The casing is shaped so as to converge towards the top while the opening is closed by a diaphragm (9') which is mounted there in a detachable or fixed manner. With this device, excessive evaporation is prevented, while at the same time the seedlings are kept moist with the minimum wastage of water. <IMAGE>
