Generally, there are three types of water feeding in edible sprouts cultivation, namely, showering type, spraying type, and soaking type. In the case of mass production of edible sprouts in a natural culturing method, that is, to culture sprouts without using any chemical fertilizer and/or pesticide, artificial ethylene, nitrogen, or antibiotic, and provided that water feeding and draining is under good control, the soaking type water feeding is usually better than the showering and the spraying type to culture sprouts of stable and high quality. (However, currently, most edible sprouts culturers directly or indirectly use the above mentioned chemicals.) However, a disadvantage of the culturing units using the soaking type water feeding commonly adopted by the culturers is high consumption of water. Moreover, it is difficult to control the volume and timing of water supply to the multiple layers of culturing units with one single water feeding means. And, the water shall have a raised temperature when it flows from units at upper layers to that at lower layers, resulting in insufficient lowering of temperature in the units at lower layers and accordingly irregular and inferior quality of the edible sprouts.
Moreover, water amount and water feeding interval required during the whole culturing process vary with different beans and seeds (such as mung beans, soy beans, small red beans, peas, etc.), as well as stages of culturing, that is, the beans/seeds soaking, the acceleration of germination, and the sprouts culturing. To complete the above three different culturing stages all in the same culturing container without the need of changing the culturing environment, it necessitates completely new sprouts culturing method and automatic water feeding system which saves time, labors, and water required to culture sprouts and thereby effectively reduces the culturing cost and increases the producer's competition ability in the market. One good way to achieve the above purpose is to culture the edible sprouts in an upstanding type farm.
An earlier invention of the inventor titled "Hydroponic means for culturing edible sprouts" which has been granted a U.S. Pat. No. 5,636,474 on Jun. 10, 1997 forms a primary framework of the present invention.