When growing onions in open fields, soil preparation is critical, as the majority of the root mass is concentrated in the top 30 cm layer. Thorough soil pulverization is required for aeration, and perfect surface leveling is necessary for uniform seed placement. Crop rotation should exclude perennial grasses and a number of cereal crops due to the high risk of pest damage, particularly wireworms.
Onions are cold-resistant: seed germination begins at 5°C, and seedlings can withstand brief frosts down to -6°C. The water regime requires maintaining soil moisture of at least 70% during the first half of the growing season, with a gradual restriction of irrigation before maturation to improve bulb storability.
The crop is sensitive to soil reaction, requiring an optimal pH above 5.5. When grown in open fields, it is necessary to avoid the application of fresh manure and chlorine-containing fertilizers during the growing season, as they negatively affect the quality and shelf life of the harvest.
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Open field.