Introduction to the Latest Planting Times for Broccoli

Broccoli originated in the coastal areas of the eastern Mediterranean. At present, it is cultivated in both northern and southern China and has become one of the main everyday vegetables. It is rich in nutrients, containing protein, sugar, fat, vitamins and carotene. Its nutritional content ranks first among vegetables of the same kind and it is known as the “crown of vegetables”. It has very high planting prospects. Now let us take a look at the planting times for broccoli!

Planting Times for Broccoli

Broccoli is usually sown in autumn, grows through winter, and comes to market normally after Spring Festival to appear on the table. In spring it begins to flower, and the seeds mature in April to May. For summer and autumn seedling raising, seedlings are raised during the high-temperature season from August to October. At this time the temperature is generally above 25℃, sometimes with high temperatures of 30-35℃, and there are also hazards from heavy rain and hail, so shade nets are used for open-field seedling raising. The seedling age is generally 35-40 days. Sowing or direct hole sowing can be used. The seedling stage averages about 30 days, and from transplanting to harvest takes 80-90 days. It is somewhat strongly winter-type; when the seedling stem is 10 mm thick it can be affected by low temperature and complete the vernalization process.

Growing Environment for Broccoli

1. Light: Broccoli is not very strict about light requirements, but during growth it likes sufficient light. When light is adequate, the plant grows robustly and can form a strong vegetative body, which is beneficial to photosynthesis and nutrient accumulation, and makes the curd compact and dense, bright green in color and good in quality. Too strong sunlight in midsummer is also unfavorable to the growth and development of broccoli.

2. Temperature: Within the range of 5-20℃, the higher the temperature, the faster the growth and development of broccoli. The most suitable germination temperature is 20-25℃, and the optimum growth temperature during the seedling stage is 15-20℃. It has strong cold resistance and heat resistance. The optimum growth temperature during the rosette stage is 20-22℃, and the optimum temperature for curd development is 15-18℃. When the temperature is above 25℃, the quality of the curd tends to deteriorate, but as long as it is not damaged by freezing, the curd can still grow slowly at low temperatures of 5℃ or even below.

3. Water: Broccoli requires a relatively large amount of water throughout its growth process, especially during vigorous leaf growth and curd formation, when it must not lack water. Even short-term drought will reduce yield. Excessive rain during the seedling stage or excessively high soil moisture easily causes diseases such as black rot and black spot. During curd formation, only when the soil moisture and field water-holding capacity are about 70-80% can the growth needs be met.

4. Soil: Broccoli does not have strict requirements for soil conditions, but if the soil is too poor, the plant develops poorly and yield and quality are low, while if the soil is excessively fertile, it will lead to loose buds and hollow flower stems. It is suitable for planting on loam and sandy loam with good drainage and irrigation, deep plow layer, loose and fertile soil, and strong water and fertilizer retention. The soil pH range is 5.5-8, but 6 is best.

Seedling Raising Techniques for Broccoli

1. Variety selection: Broccoli is a vegetable that prefers cool conditions. Choose varieties with strong plant growth vigor, dark green buds, few scorched buds, arc-shaped round curds, few side buds, small buds, large curds, disease resistance, heat tolerance, cold tolerance and wide adaptability, such as Japan's Youxiu, Longlu and Shanshui, or other varieties such as Yuguan, Dongfang Lubao, Wanlu and Luxiu, or choose various high-quality varieties according to market demand, but they must meet the national second-grade seed standard before use.

2. Sowing time: For autumn double-cover cultivation, sow in early July; for overwintering cultivation in sunlight greenhouses, sow from late July to August; for early spring cultivation in sunlight greenhouses, sow from early September to early October; for early spring cultivation in plastic tunnels and small arches, sow in November; for spring plastic film cultivation, sow in January.

3. Seed treatment

① Seed soaking: Soak the seeds in warm water at 33℃ for 15 minutes, stirring constantly. When the water temperature drops to 20℃, stop, continue soaking in warm water for 4 hours, rinse clean with clear water, and then germinate.

② Germination: Wrap the soaked seeds in moist cotton gauze and germinate them at 30℃. Rinse once a day with clear water, and sow when 60% of the seeds have sprouted white.

4. Open-field seedling raising

① Seedbed selection: The seedling stage of broccoli is relatively short. Choose a seedbed on land that is high in terrain, convenient for drainage and irrigation, rich in organic matter, and has not grown cruciferous vegetables within two years or whose previous crop was rice. The seedbed should preferably run north-south.

② Apply sufficient base fertilizer: Deep plow 15-20 days before sowing. Apply 15 kg of ternary compound fertilizer plus 5 kg of superphosphate per mu 7-10 days before sowing, or splash-apply 2500 kg of decomposed human manure and urine, to ensure sufficient nutrient supply during the seedling stage. Turn and rake the soil broken, and make a sowing bed about 1.2 m wide, with a seedling field ratio of 1:20-30.

③ Mix with pesticide and sow: Water the seedbed thoroughly once before sowing, and apply 1000-fold phoxim and other pesticides to prevent underground pests. When sowing, mix the treated seeds evenly with an appropriate amount of sand and spread them evenly in the seedbed. After sowing, press with an iron shovel, then scatter a layer of medicinal soil mixed with 0.1% carbendazim and dexon.

④ Shade and heat preservation: In summer, spread a layer of shade net flat on the seedbed, then set up a small arch, and cover another layer of shade net to carry out double-layer shading, moisture retention and cooling for seedling raising. In winter and spring, use one layer of plastic film and one layer of greenhouse film to carry out double-film mulching for heat preservation seedling raising.

5. Nutrient solution seedling raising: Nutrient solution seedling raising is currently a relatively good seedling raising method. It has the characteristics of low cost, convenient management, high seedling survival rate, and centralized seedling supply, and is welcomed by production and processing enterprises.

① Substrate: vermiculite 25%, peat 65%, perlite 10%.

② Substrate stacking and disinfection: After fully and evenly mixing all raw materials, use 50-100 fold formalin (40% formaldehyde) and spray it evenly on the substrate. Then cover it tightly with plastic film and keep it sealed for 4-5 days. After that, remove the film for ventilation and turn the nutrient soil so that the formaldehyde volatilizes away. It can be used after 2 weeks, and the pH of the substrate needs to be adjusted to 6.5-7. If too acidic, adjust with lime; if too alkaline, neutralize with dilute hydrochloric acid.

③ Sowing: Fill the plug tray with substrate, water thoroughly, then use a special hole-punching machine to make sowing holes, use a seeder to sow the seeds into the sowing holes, and cover with substrate.