PURPOSE:To protect a plant from the cold of winter night simply by leaving a culture vessel in a warm room during day time, by using a plant culture vessel having double-wall structure and placing plural latent-heat accumulation materials sealed in plastic bags in the hollow part of the double-wall. CONSTITUTION:A plant culture vessel 3 has a double-wall structure. A latent- heat accumulation material 5 is sealed in a plastic bag 4 and a plurality of the materials 5 are placed in the hollow part of the double wall. The latent-heat accumulation material 5 has a phase-transition temperature of preferably 5-20 deg.C. Preferable examples of the material are Thermotop 15 (commercial name, product of Asahi Denka Co.) and 1-17C paraffins. The plastic bag 4 is preferably a bag made of vinylidene chloride resin, polycarbonate, polyester, etc. Since the latent-heat accumulation material 5 is sealed in the bag 4, the leak of the accumulation material 5 can be prevented even if cracking or crazing takes place in the culture vessel 3.
