Method of enhancing plant growth using light levels lower than photo saturation intensity

• US 5,174,793 A
• Filed: 12/23/1988
• Issued: 12/29/1992
• Est. Priority Date: 10/28/1983
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakayama, Shigeki, Ishii, Toshitsugu, Ikeda, Akira, Ezaki, Kenji
• Primary Examiner(s): DeMille, Danton D.
• Application Number:
  US07/266,610
• Time in Patent Office: 1,467 Days
• Field of Search: 47/17, 47/DIG. 6, 47/58, 47/82, 47/39, 47/60
• US Class Current: 47/58.10R
• CPC Class Codes: A01G 7/02 Treatment of plants with carbon dioxide
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses
• CPC Class Codes: Y10S 47/06 Plant growth regulation by control of light thereon

Abstract

A method of plant cultivaton and growth acceleration includes enclosing the plants within a reflective chamber, controlling the CO₂ concentration within said chamber so as to be at least 200 ppm, and irradiating the plants substantially omnidirectionally with a light intensity of approximately 3000 lux, while stably regulating the ambient temperature, relative humidity and nutrient supply.

Claims

1. A method of enhancing the growing speed of a plant by controlling at least the light intensity and CO₂ concentration comprising the steps of:

determining the photo saturation intensity of said plant, comprising a light intensity limit for such plant above which photosynthesis velocity is not increased,

maintaining the CO₂ concentration at 200-4,000 ppm, and

illuminating the plant by directing light to the plant from substantially upper and lower sides of said plant and from all circumferential directions inwardly towards said plant simultaneously and uniformly and controlling said light intensity so as to be lower than said photo saturation intensity with respect to said plant being grown.

2. A method of enhancing the growth speed of a plant having a known photo saturation intensity, comprising a light intensity limit for such plant above which photosynthesis velocity is not increased, by controlling at least the light intensity and CO₂ concentration, comprising the steps of maintaining the CO₂ concentration at 200-4,000 ppm and illuminating the plant by directing light to the plant from substantially upper and lower sides of said plant and from all circumferential directions inwardly toward said plant simultaneously and uniformly and controlling said light intensity so as to be lower than a photo-saturation intensity with respect to said plant being grown.

3. The method as claimed in claim 2, wherein said illumination of said plant is carried out continuously, 24 hours per day.

4. The method as claimed in claim 2, wherein said light intensity is at least approximately 15K lux.

5. The method as claimed in claim 2, wherein said light intensity is from one-seventh to one-half of said photo-saturation intensity.

6. The method as claimed in claim 5, wherein said CO₂ concentration is higher than the CO₂ concentration of atmospheric air.

7. The method as claimed in claim 2, wherein a period of said illumination step is longer than 12 hours per day.