Multistage plant culture method and multistage plant culture apparatus for use therein

A multistage plant culture method using a plant culture apparatus having a plurality of stages at different heights for supporting culture beds, each culture bed containing plants, comprising the steps of:

• arranging at least one of the culture beds on an uppermost one of the stages;
• determining a planned harvest period H during which fruit may be harvested from the plants and a planned whole culture period T1 which is the period from seeding, cutting and grafting of the plants to the end of the harvest of the fruit from the plants,
• maintaining the plants on each of the stages for a predetermined culture period equal to the planned harvest period,
• removing any of the culture beds on a lowermost one of the stages from the lowermost stage after the planned harvest period H, the plants in the culture bed(s) in the lowermost stage remaining in the lowermost stage during the planned harvest period and being harvestable while therein;
• moving down the culture beds in order from the uppermost stage to the lowermost stage after the plants have been maintained on each stage for the predetermined culture period such that the uppermost stage is vacated;
• placing a new one of the culture bed containing the plants grown for a seedling raising period P on the vacant uppermost stage;
• repeating said culture bed removing step, said culture bed moving down step and said new culture bed placing step,
• determining a number N (N=integer) of the stages of the plant culture apparatus so as to satisfy a formula H.times.N.ltoreq.T1, and
• determining the seedling raising period P for the plants from the time of the seeding, the cutting and the grafting of the plants until the moving of the new culture bed containing the seeded plants onto the uppermost stage so as to satisfy a formula P=T1-(H.times.N).