Causes of and Prevention Measures for Premature Bolting in Radish

The phenomenon in which radish only bolts and flowers without forming a root underground, or without growing a large root, is called premature bolting, also known as immature bolting. Most radish varieties can pass through vernalization after 10-20 days of low temperature and bolt early, but different varieties respond to low temperature to different degrees. So why does radish bolt prematurely? Let's find out together.

I. Causes

1. Temperature

Radish is a biennial crop. In the first year it undergoes vegetative growth, and after low-temperature storage through winter, it bolts and flowers in the second spring. At this time, the flower bud differentiation of radish requires low-temperature conditions. This requirement of low temperature for flower bud differentiation and subsequent flowering is called vernalization. Different varieties require different temperatures and durations. Generally, northern varieties require lower temperatures and longer durations, while southern varieties require higher temperatures and shorter durations. In the same region and the same season, different varieties have different low-temperature requirements. Generally, winter-spring type varieties require lower temperatures and longer durations, while summer-autumn type varieties can also pass through the vernalization stage at higher temperatures. Small varieties have stricter vernalization requirements and are less prone to bolting, while large varieties are more prone to bolting than small ones. When sown in spring, later sowing can also cause some plants to bolt and flower.

2. Light

Radish is a long-day plant. Under long-day conditions, flower bud development and bolting are promoted, so long-day conditions are a necessary condition for radish flowering and bolting. Therefore, spring cultivation is more prone to bolting than winter cultivation. This is because although winter temperatures are low, the growing point has already undergone flower bud differentiation, and the short daylight hours in winter do not satisfy the conditions for flower bud differentiation. So if you want radish not to bolt, it is best to keep the seedling stage above 11°C, and maintain cool weather as much as possible during the growing period.

II. Prevention Measures

1. Select excellent varieties

It is necessary to understand the low-temperature vernalization requirements of different varieties, especially spring cultivation varieties. If a southern variety is planted in the north and sown in early spring, bolting will occur. If introduced and planted from a locally cooler low-temperature area, premature bolting is less likely to occur.

2. Ensure proper timing

Once you understand the temperature conditions required for flower bud differentiation of the planted variety, the sowing time and temperature should be higher than its vernalization temperature, so that it will not bolt or will bolt less.

3. Temperature regulation

In terms of overall temperature regulation, the early stage is a high-temperature maintenance period, and the later stage is a low-temperature control period. That is, keep high temperatures at the seedling stage to promote seed germination and seedling growth and avoid low-temperature vernalization. Therefore, the sowing time, early or late, must be based on the effect that heat preservation can achieve. If heat preservation is difficult, the sowing date must be delayed.

4. Strengthen management

Before sowing, the soil must be plowed. Use decomposed organic fertilizer as base fertilizer, cover the prepared land with plastic film, and build arched sheds. Sow when the shed temperature is stable above 11°C. After sowing, keep the shed closed to prevent low temperatures. When the temperature is above 25°C, ventilate appropriately to cool down. After the temperature rises, increase ventilation at noon. When the fleshy root expands, it is advisable to maintain a temperature of 18-20°C to prevent high temperatures from inhibiting growth.

The above is an introduction to the causes of and prevention measures for premature bolting in radish. We hope it helps you. For more related knowledge, please stay tuned to us.