Sustainable Management of Rose Growing in Greenhouse Heated by Geothermal Water at Kuju, Japan

Abstract

Hand Flower Producing Union has been growing roses for cut flowers in 20 green houses in Kuju, Oita, Japan, for more than 10 years since 1991. The union consists of 10 farmers and grows roses in the green houses that have been partly heated with geothermal water produced from a 550 m depth well. A submersible pump has been installed and produces 1.7 kg/s of geothermal water at 106 oC. The water is then mixed with the heat-depleted water flowing out of the houses to make 70 to 75 oC water. This water flows through finned tubes in the green houses for heating. The annual product of roses reaches 1.6 million stems and all the roses are shipped to Tokyo where good prices of flowers can be realized. The basic design of the heating system and of the growing system of roses is introduced as an example of sustainable management of green house farming.