Key Technical Points for Standardized Production of Bean Sprouts in Greenhouses

Bean sprouts, also known as sprouting vegetables, are edible "sprouts" cultivated from the seeds of various grains, legumes and trees, and are also called "living vegetables." Common sprouting vegetables include: Chinese toon sprouts, buckwheat sprouts, alfalfa sprouts, Sichuan pepper sprouts, green black bean sprouts, jequirity bean sprouts, sunflower seed sprouts, radish sprouts, dragon whisker bean sprouts, peanut sprouts, broad bean sprouts and more than 30 other varieties. They are rich in variety and comprehensive in nutrition, and are a common vegetable. The main part eaten is the hypocotyl.

Traditional bean sprouts refer to soybean sprouts, and later new varieties such as mung bean sprouts, black bean sprouts, pea sprouts and broad bean sprouts were gradually developed on the market. Although bean sprouts are all cold in nature and sweet in taste, their effects differ. Mung bean sprouts are easy to digest and have the effects of clearing heat and detoxifying, and promoting urination and removing dampness, making them suitable for people with damp-heat stagnation, dry mouth and thirst, hot and reddish urine, constipation, and red swollen painful eyes. Soybean sprouts strengthen the spleen and nourish the liver, and have a relatively high vitamin B2 content; eating an appropriate amount of soybean sprouts in spring helps prevent angular cheilitis. Black bean sprouts nourish the kidneys and are rich in calcium, phosphorus, iron, potassium and other minerals as well as various vitamins, at higher levels than mung bean sprouts. Pea sprouts protect the liver, and are rich in vitamin A, calcium, phosphorus and other nutrients; broad bean sprouts strengthen the spleen, and have the effects of supplementing iron, calcium, zinc and others.

Standardized Production Technology for Bean Sprouts in Greenhouses

Seed selection

Greenhouse bean sprouts are mainly soybean sprouts, followed by mung bean sprouts. When selecting seeds, broken grains and impurities should be removed, and the seeds should be soaked in warm water at 40°C for 5 hours, then removed, drained and pre-germinated, with the pre-germination temperature kept at about 18°C. The cultivation beds are 1.3 m wide and 7 m long. The soil dug out from the beds is sieved and stored on the bed ridges for later use, and the bed surface is leveled ready for sowing.

Bed preparation

In a 20 m long greenhouse, 18 beds are built, each bed surface 1.3 m wide and 7 m long, with bed ridges 63 cm high and 63 cm wide, and trampled firm. The soil dug out from the beds is sieved and stored on the bed ridges for later use, and the bed surface is leveled ready for sowing.

Sowing

Spray water at a rate of 5 kg of water per square meter of bed surface, evenly scatter the soaked seeds on the bed surface, then cover with 5 cm of sieved fine soil, then level the bed surface and cover with plastic film.

Management

The bed soil moisture is kept at about 60%, and not more than 70%. On the 1st day, the bed soil temperature is 18°C or normal temperature; on the 2nd and 3rd days, 24°C; on the 4th day, 22°C; on the 5th day, when the bean sprouts break through the soil and emerge, not more than 20°C.

Harvesting

Bean sprouts need only 6 days to grow; at this time the bean sprouts are 10 to 12 cm long and the cotyledons appear neither fully open nor closed, which is the suitable harvest period. They can be pulled with one hand while held with the other, and washed clean of mud and sand with clear water, then tied in bundles of 0.5 kg for sale on the market.

Precautions

Replace the covering soil once a month, disinfect with 2% lime water, and air the beds for one day in each cultivation cycle. During the growth period, pay attention to shading to prevent the bean sprouts from turning green and affecting quality.