Detailed Explanation of Sprout Production Methods and Technical Points

Sprouts, also called sprouting vegetables, in addition to the several commonly eaten bean sprouts, have in recent years also been produced using crop seeds, roots, stems, branches, and other propagation materials under low-light and suitable-temperature conditions to grow sprouts, sprout bulbs, tender shoots, young stems, or young tips for consumption. They are fresh and tender in quality, rich in nutrients, pollution-free, and have health benefits, making them very popular with consumers. Moreover, sprouts have a short growth cycle and high biological efficiency, capable of producing 4 to 8 times the yield of the seeds, with very significant economic benefits. However, producing sprouts also requires certain techniques, mainly as follows:
1. Types of Sprouts
① Seed sprouts. The nutrients stored in seeds are used to directly cultivate tender sprouts or seedlings. In addition to the common soybean, mung bean, black bean, and broad bean sprouts, seeds of crops such as peas, radish, Chinese toon, and buckwheat can also be used as raw materials to cultivate dragon-beard pea sprouts, Chinese toon seedlings, buckwheat sprouts, and radish sprouts for the market, becoming a new type of vegetable favored by urban and rural residents.
② Body sprouts. The nutrients stored in biennial or perennial roots, fleshy taproots, rhizomes, or branches are used to cultivate edible sprout bulbs, tender shoots, young stems, or young tips. For example, bitter lettuce and dandelion (tender shoots or young tips) cultivated from perennial roots; chicory sprout bulbs cultivated from chicory and fleshy taproots under dark and suitable-temperature conditions; ginger sprouts, asparagus, and bamboo shoots (young stems) cultivated from rhizomes; and Chinese toon sprouts and goji tips (tender shoots) cultivated from planted stems and branches all belong to body sprouts.
2. Cultivation facilities. The suitable growth temperature for various sprouts is mostly 20 to 25°C (peas require 18 to 23°C). When the outside temperature is above 18 to 20°C, they can be cultivated in the open air, but appropriate shading is needed, along with increased water spraying to maintain moisture. In winter, early spring, and late autumn, energy-saving solar greenhouses, arched plastic tunnels, and buildings can be used for cultivation, with cultivation equipment prepared in advance.
① Cultivation racks. To utilize multi-layer three-dimensional cultivation, angle iron, steel bars, bamboo, and wood can be used to make 3 to 5 layer cultivation racks, with a spacing of 30 to 40 cm between layers, and the width determined by the length of the seedling bed. For ease of operation, the rack height generally does not exceed 1.5 m.
② Containers and substrate. Plastic seedling trays are generally chosen as cultivation containers, with specifications of about 60 cm long, 25 cm wide, and 5 cm high. Plastic baskets with small mesh holes, fruit trays, and the like can also be used. White paper (or old newspaper), white cotton cloth, river sand, perlite, and the like can be chosen as substrate.
③ Water spraying facilities. To ensure the water requirements during sprout growth, the substrate must be kept moist, so spraying must be strengthened. For large-area cultivation, micro-spray facilities should be installed; for smaller areas, sprayers and watering cans should be available.
3. Cultivation techniques.
At present, the most commonly produced is mainly pea sprouts, followed by radish, Chinese toon, buckwheat sprouts, and the like, and their cultivation points are roughly similar. The main cultivation techniques are:
① Strict seed selection. In sprout cultivation, new seeds with a germination rate above 95%, high purity and cleanliness, and plump grains should be selected. Especially for Chinese toon seeds, which easily lose germination ability under high-temperature conditions, even more attention should be paid to selecting new seeds that have not gone through summer (rub off the wings before use). Using such seeds to cultivate sprouts results in seedlings that grow quickly, are sturdy, have less fiber, good quality, and also high yield.
② Seed soaking and germination. Wash the seeds 2 to 3 times with clean water at 20 to 30°C, then soak the seeds in water 2 to 3 times the seed volume. The time is slightly longer in winter and slightly shorter in summer; generally, peas are soaked for 18 to 24 hours, Chinese toon for 12 to 20 hours, buckwheat for 24 to 36 hours, and radish for 6 to 8 hours. After soaking, rub off the mucilage from the seed coat, place the seeds in a flat-bottomed container, cover with a wet towel, and germinate peas at 18 to 23°C, radish and buckwheat at 23 to 26°C, and Chinese toon at 20 to 23°C. When the sprouts grow to 2 to 3 cm, they can be sown.
③ Sowing. Wash the sowing trays, spread 1 to 2 layers of white paper (or old newspaper) on the bottom of the trays, and let the paper absorb enough water. Evenly scatter the germinated seeds on the wet substrate. Generally, the sowing amount for a 60×25×5 cm tray is: peas 350 to 400 g, buckwheat 150 to 170 g, radish 80 to 100 g, Chinese toon 30 to 50 g. After sowing, neatly stack the seedling trays together and cover them with black plastic film; stack the trays for germination with peas at 18 to 23°C, buckwheat and radish at 30 to 25°C, and Chinese toon at 20 to 23°C. After 2 days, when the sprouts are 2 to 3 cm high, the trays can be placed on the racks and grown in light.
④ Sprout management. Light: buckwheat sprouts and radish sprouts require relatively strong light, Chinese toon seedlings require moderate light, and pea sprouts have broad adaptability. During the mid-growth period of sprouts, light should not be too strong, otherwise cellulose forms early and affects quality; if light is too weak, sprouts tend to become thin and weak, leading to lodging and rotting. Water: because sprouts themselves are fresh, tender, and juicy, water must be replenished frequently, spraying 2 to 3 times a day, to the extent that the substrate in the tray is moist without large amounts of dripping water. Spray more in hot, dry weather, and less on rainy days or when the temperature is low. Ventilation: appropriate ventilation must be carried out every day in conjunction with adjusting temperature and humidity.
4. Harvesting. Sprouts use tender stems and leaves as the product; the tissue is tender and has the highest water content, and they are mostly sold as whole live trays. The harvest standards are as follows: Pea sprouts: sprouts light yellow-green, 10 to 12 cm high, top cotyledons unfolded, tender without fiberization. Chinese toon seedlings: sprouts dark green, 8 to 12 cm high, cotyledons unfolded, heart leaves not yet emerged, rich fragrance. Buckwheat sprouts: sprout cotyledons green, hypocotyl red, 12 to 15 cm high, cotyledons flat and fully enlarged. Radish sprouts: sprouts emerald green, 8 to 10 cm high, cotyledons flat and enlarged.