Detailed Explanation of Key Points for Japanese Cold Onion Cultivation Techniques

Japanese cold onion is a highly cold-resistant superior onion variety successfully selected and bred from Japanese cold onion by the Special Excellent Melon and Vegetable Research Institute of Heze Prefecture, Shandong Province. This variety has characteristics such as short leaves, heavy wax bloom, long and firm white stalks, early maturity, high cold resistance, and fast growth speed. Generally, seedlings are raised within 10 days before and after the Beginning of Autumn, cultivated in October, marketed in spring, and do not need protection in winter.

Seedling raising: The suitable time for seedling raising is from July 20 to August 20. Select fertile sandy soil with high and dry terrain that is not prone to water accumulation for the seedbed, prepare the land and make beds, with a bed width of 1.5-2.0 m and unlimited length. Apply 50 kg of high-quality compound fertilizer per mu to the seedbed, rake and harrow finely, then water to create soil moisture. After the water seeps down, mix the seeds with soil and evenly scatter them on the bed, then use 5% phoxim granules mixed with fine soil and scatter evenly, then cover with fine soil 2 to 3 cm. If conditions permit, cover with straw mats to protect from sun and rain. For every 667 sq m of Japanese cold onion planted, 500 g of seeds are needed, and the seedbed should be 150 sq m.

Planting: From October 10 to November 10, after the previous crop is harvested, promptly prepare the land and apply fertilizer. Generally, for every 667 sq m, apply 3000 kg of high-quality organic fertilizer, 50 kg of ternary compound fertilizer, 25 to 30 kg of urea, and 25 to 30 kg of potassium fertilizer along the plow sole. After leveling, make beds with an east-west orientation, bed width of 30 cm, height of 25 cm, level and cover with plastic film. When planting, pull out the onion seedlings, let them dry slightly, use a bamboo stick to insert the seedlings under the film, with row spacing of 18 cm and plant spacing of 8-12 cm, planting about 15,000 plants per mu, then straighten them and water with seedling recovery water.

Winter and spring management: After winter begins, before the cold wave arrives, water the freezing water well. After Great Cold, with the Beginning of Spring approaching, temperatures in the north gradually rise, so water and fertilize in time. In the early stage when temperatures are low, water lightly according to soil moisture conditions to prevent flooding irrigation. After Awakening of Insects, when the ground is completely thawed, combined with watering, apply 30 kg of urea per mu as topdressing. In order to harvest earlier, farmers with conditions can add small arch sheds before the Beginning of Spring to keep the temperature at around 20°C. If it exceeds 30°C, ventilate and exchange air in the morning in time. After the weather warms up, the onion seedlings grow faster, and at this time they are prone to bolting and budding. After budding, promptly remove the flower buds to transform the onion from reproductive growth to vegetative growth, so as not to reduce the quality of the onion.

This variety can also be raised from September 20 to October 10, cultivated and managed the same as other onion varieties, and the yield per mu can reach more than 7000 kg.