Detailed Explanation of the Key Cultivation Techniques for Japanese Mitsuba

I. Sowing and Seedling Raising 1. Sowing Period Mitsuba (Japanese mitsuba) sown in the open field in spring should be sown when the soil temperature is stable above 5°C; sowing in a solar greenhouse is not limited by season, and is generally done in mid-to-late October when the film is put in place and sowing is carried out. 2. Site Selection and Soil Preparation Mitsuba prefers fertile, loose loam or sandy loam soil with a pH of 5-7. Before sowing, deep-plow the soil about 30 cm, apply about 3,000 kg of thoroughly decomposed high-quality farmyard manure per mu, mix well, and then make low beds about 1.2 m wide, about 15 cm deep, and 10-20 m long, with bed ridges 30 cm wide. 3. Sowing Method and Seed Rate Rake the bed surface level, then water thoroughly to saturate the soil. At a seed rate of 10 g per sq m, mix the seeds evenly with fine sand or fine soil and broadcast them, then cover with 0.3-0.5 cm of soil. 4. Seedling Stage Management About 10 days after sowing mitsuba, the cotyledons emerge. At this time, for open-field sowing, choose a cloudy day or the evening to remove the plastic film, and afterward water appropriately according to weather conditions; for solar greenhouse sowing, manage the greenhouse temperature well, keeping the daytime temperature at about 20-25°C and the nighttime temperature no lower than 5°C. When the first true leaf unfolds, thin the seedlings to a spacing of 2 cm, water after thinning, and afterward control water appropriately to harden the seedlings. After the 3rd true leaf unfolds, transplant and set out the seedlings.

II. Year-Round Cultivation Techniques in a Solar Greenhouse 1. Soil Preparation and Bed Making Deep-plow the soil about 30 cm, apply 3,000 kg of farmyard manure per mu, and make four long beds along the east-west lengthwise direction. Leave 50 cm wide at the front foot of the greenhouse for a bed ridge, leave 30-40 cm wide at the base of the back wall for a bed ridge, and make the middle 3 bed ridges each 30-40 cm wide, with a bed width of 1.5 m. Inside the greenhouse, install two micro-sprinkler water supply pipe lines along the east-west direction at a height of 35-40 cm above the ground. 2. Transplanting, Setting Out, and Management Rake the bed surface level, and transplant and set out the seedlings at a hole spacing of 10 cm x 10 cm, with 3 plants per hole. After planting is completed, start the water pump to spray water. At this time, raise the greenhouse temperature appropriately, with the daytime temperature at about 25-28°C and the nighttime temperature at about 20°C. After 2 days, the seedlings recover; at this point lower the temperature, controlling it at 20-25°C during the day and about 10°C at night. Mitsuba likes a moist environment, so spray a thorough watering about every 5 days and apply fertilizer water once every 15 days. To improve the quality of the greens, appropriately control light to achieve the purpose of blanching cultivation. In winter and spring, use internally hung shade nets (50%-60% shading) for shading; in summer and autumn, use Liso spray coating for shading and cooling. After each harvest, broadcast 1-2 kg of organic fertilizer per sq m, and the interval for topdressing is the same as before. 3. Harvesting When the seedlings are about 30 cm tall, use a knife to cut flat at 2-3 cm from the base of the plant. Be careful not to cut off the growing point, and the stubble left should not be too high either, otherwise it will affect the yield and the growth of the next crop.