What causes abnormal cauliflower curds? Here comes the cause analysis

Recently, several vegetable growers reported that in cauliflower cultivation, abnormal curds often appear, and asked what this is about and how to prevent it. On this issue, based on years of cultivation experience, the author now introduces the common abnormal manifestations and their causes as follows:

1. Premature curd formation

At the seedling stage, the curd appears before vegetative growth has fully developed. Causes: passing through the vernalization stage too early, generally when autumn-sown varieties are used in spring, or when spring sowing is too early and low temperatures cause early vernalization; seedling-stage temperatures are too low, or autumn sowing is too late. The solution is to sow at the right time and strictly control the seedling-stage temperature.

2. No curd formation

Only stems and leaves grow, with no curd formed. The cause is that autumn-sown varieties are sown too early, when temperatures are relatively high, so the seedlings do not undergo low-temperature treatment and do not pass through the vernalization stage, and only grow stems and leaves without forming a curd; too much nitrogen fertilizer is applied during the vegetative growth period, and there is no seedling root-restricting to control vigorous growth, resulting in excessive vegetative growth. The solution is to sow at the appropriate time, create the conditions for cauliflower to pass smoothly through the vernalization stage, and properly restrict growth during the rosette-leaf stage so that vegetative growth shifts to reproductive growth.

3. Small curd

At harvest, the curd is too small and does not meet market requirements. The main causes are impure seed, with spring-sown varieties mixed with autumn-sown varieties, or autumn-sown mid-to-late-maturing varieties mixed with a small number of early-maturing varieties; old, weak, or diseased seeds have weak growth vigor, with poor stems and leaves, pass through the vernalization stage earlier, suffer from poor nutrition, and form small curds; insufficient fertilizer and water, saline-alkali soil, and damage from pests and diseases; improper sowing time, with autumn sowing too late and lower temperatures, causing the variety to pass through the vernalization stage at the seedling stage and form a small curd. Solutions: select pure seed, match varieties with the proper sowing time, provide proper water and fertilizer, and choose fertile plots.

4. Green curd

Green bracts or sepals grow prominently on the surface of the curd, making the curd appear green. The cause is that during the curd enlargement period, direct sunlight strikes the surface of the curd, and the curd first turns from white to yellow, then to green. To prevent green curds, tie the leaves in time during the heading stage, or bend some old leaves to cover the curd and prevent direct sunlight.

5. Hairy curd

Hairy curd is the non-sequential elongation of the flower columns or filaments of the floral organs at the top of the curd's flower branches. It is caused by sudden temperature drops, temperature rises, or heavy foggy days when the curd is nearing maturity. Preventive measures are to sow at the right time; when transplanting, the seedling age should not be too old, generally 5-6 true leaves and about 25 days is suitable, and weak seedlings and "small old seedlings" should be avoided. Cultivate and loosen the soil frequently to promote recovery after transplanting. Apply topdressing early, focusing on promoting growth, and apply a compound fertilizer once each at the bud stage and the curd enlargement stage, avoiding excessive nitrogen fertilizer. When drought and water shortage occur, water in time to keep the soil moist. During long periods of high temperature and strong light or when low-temperature weather occurs, remove leaves in time to cover the curd.

6. Purple curd

Purple curd is caused when the curd is nearing maturity and suddenly encounters low temperatures, converting glycosides into anthocyanins, with uneven red and purple appearing on the surface. The main causes are strong sunlight on the curd, or a sudden low temperature after the curd has formed, which causes components in the curd tissue to convert into anthocyanins; early-maturing varieties cultivated in autumn are especially affected. To prevent purple curds, choose suitable excellent varieties and sow at the right time so that temperatures are appropriate at each growth stage. When the curd grows to 3 cm in diameter, gently bend 1-2 outer leaves near the curd so that they cover the curd. If low temperatures occur during the curd growth period, cover the curd to prevent freezing, and old leaves at the base can be picked to cover the curd.

Wang Guiren, Yaozhai Yanmen Agricultural Association, Handan County