It comprises a support means (1, 2, 3, 8) resting on the soil and on which are arranged several bundles (9, 9a, 9b) of tubes in which a heating fluid circulates, the said bundles (9, 9a, 9b) being fixed under a container (11) in which the plants (7) are arranged. The invention is used in greenhouses for the culture of plants. <IMAGE>