Causes of Deformed Onions and How to Prevent and Treat Them

Onion, also known as scallion head and round onion, is a fairly common vegetable, and because of its relatively high economic returns, its planting area is growing ever wider. However, deformities can appear during the growing process, which seriously affects the onion's commercial value and brings economic losses to farmers. So what causes onion deformities? Read on with the editor below to learn the prevention and control methods, and keep losses to a minimum.

1. Seed causes

Onions have been cultivated for a long time and there are many varieties. In many regions, when introducing varieties, the local environment was not taken into account, causing the seeds to be unsuited to the local environment. For example, varieties with weak winter hardiness are more sensitive to low temperatures, and when introduced to areas with a lower average annual temperature, they bolt as soon as they encounter low temperatures; while varieties with strong winter hardiness must sense low temperatures before they bolt and flower.

Prevention and control methods: Choose excellent varieties suited to the local environment for cultivation, and select varieties suitable for local planting based on how the variety responds to temperature levels and day length.

2. Climate causes

Onion is a typical biennial plant of the seedling vernalization type. Only when the seedling grows to a certain extent does it respond to low temperatures. If cold air or relatively low temperatures occur during this stage, the seedling will shift from vegetative growth to reproductive growth. Over time, vernalization occurs and causes bolting and flowering. If the temperature is too low, the temperature cannot complete vernalization, causing abnormal differentiation of the bulb and resulting in deformed growth.

Prevention and control methods: Strengthen management. A greenhouse method can be used to control the temperature artificially so that vernalization is complete and bulb growth is promoted.

3. Nutrient imbalance

When fertilizer application favors nitrogen fertilizer and irrigation is excessive, the seedlings will grow excessively, inhibiting or delaying bulb formation, and during low-temperature periods they will also bolt and flower early. When nitrogen fertilizer is insufficient and the soil is dry, the seedlings grow thin and weak and enter reproductive growth early, showing bolting and flowering, which also leads to deformed bulbs.

Prevention and control methods: Fertilize rationally; in particular, the amount of nitrogen fertilizer applied must be controlled. Apply nitrogen fertilizer in the early stage to promote seedling growth, but not too much. In the middle and later stages, apply little or no nitrogen fertilizer, and increase the application of phosphorus and potassium fertilizers, which can increase yield.

4. Planting too deep

During the planting process, planting too deep or too shallow will both lead to abnormal bulb growth or poor development. If planted too deep, the leaves grow too vigorously, the base of the bulb thickens, and the bulb is too small and deformed; if planted too shallow, the plant easily lodges, and the bulb may even be exposed above the ground and turn green and crack over time.

Prevention and control methods: The planting depth must be appropriate, neither too deep nor too shallow. If the soil is loose, plant somewhat deeper; if the soil is heavy and sticky, plant appropriately shallow.

The above is an introduction to the causes of deformed onions and the prevention and control methods. We hope it can help you. To learn more related knowledge, please keep following us.