The root system of onion is very shallow and is considered as linear fibrous root. Weak energy absorption and water resistance. When humidity is high, it will affect tuber expansion. It is better to plant onions in sandy loam with rich organic matter and strong water retention. Considering plant spacing during planting is beneficial to field management and economic yield increase in the later stage. Onions grow well in loose and fertile soil, yielding thousands of kilograms per mu. Sow base fertilizer when the soil is wet and dig deep into the soil. It is generally recommended to apply high-quality farmyard manure, phosphorus and potassium fertilizer per mu, and the later ditching distance is 10- 12 cm. Water and fertilizer are indispensable factors for the growth rate of crops. It is best to keep the soil moist when watering onions. After squatting, water every five days to promote the rapid expansion of bulbs. After the spring flag turns green, the watering time should be controlled to avoid affecting the growth and development of plants too early or too late.

Onion is a fertilizer-loving crop. Enter the vegetative growth and tuber expansion period, and absorb fertilizer quickly. Potassium fertilizer, nitrogen fertilizer, calcium fertilizer and phosphate fertilizer are the most needed fertilizers. Therefore, phosphate fertilizer, potassium fertilizer and calcium fertilizer should be the main fertilizers in the late stage of topdressing, while maintaining the continuous supply of nutrients, and adding topdressing such as calcium, magnesium and boron to promote the stable yield increase of onion oil. Onions are wet to avoid stains. Early seedlings are small, the temperature is low, the water demand is small, and they can keep moist. After the warm spring, the temperature is getting higher and higher, and onions grow faster and faster, forming a large number of bulbs. When it enters the expansion period, it needs more water and enough water. But when it rains a lot in spring. In order to prevent water accumulation in the field, it is necessary to drain water in time.

When the leaves of plants gradually turn yellow and the basal leaves begin to dry up, onions have stopped growing and expanding, so they should be harvested in time. When harvesting, cut off the onion seedlings, try not to damage the onions, which is convenient for storage and transportation. The bulb grows very fast during the expansion period, mainly because his condition has been growing. It is prone to lodging and its leaves turn yellow. If there is ultra-low temperature during this period, or more nitrogen fertilizer is applied, basically no fruit will be harvested, and it is easy to be greedy or lodging. For onion bolting early, before the flower bulb is formed, it should be cut from the lower part of the flower bud or separated from the top of the flower stem and torn from top to bottom to prevent flowering from consuming nutrients, promote the growth of lateral buds and form fuller bulbs.