How to grow oil-green choi sum? Detailed guide to planting time and methods
SummaryVariety selection: oil-green No. 12 early choi sum, oil-green Sijiu (No. 31 choi sum) and Dongguan 45-day choi sum varieties. Site selection and land preparation: choose fertile, loose, organic-matter-rich loam or sandy loam. Planting time: the suitable sowing period is May to October, with a seeding rate of 400-500g. Shade net covering: after sowing, cover with cool gauze to retain moisture. Fertilizer and water management: apply decomposed pig manure and compound fertilizer. Pest and disease control: use agents such as Yeban Jing and Caifengning for control.
1. Selecting varieties
Early-maturing oil-green choi sum varieties are used fairly widely, among which oil-green No. 12 early choi sum, oil-green Sijiu (No. 31 choi sum) and Dongguan 45-day choi sum all have the characteristics of heat tolerance and relatively strong resistance, as well as higher yield and better quality.
2. Site selection and land preparation
1. Early-maturing oil-green choi sum is relatively tolerant of fertilizer, and in production it is necessary to choose fertile, loose, organic-matter-rich loam or sandy loam for planting, so that the flowering stalks are thicker and sturdier, the yield is higher and the quality is better.
2. Before sowing, plow deeply and sun the ridges, then apply sufficient base fertilizer and prepare the land finely so that the bed surface is turtle-back shaped, with no large pores or cracks. Generally the bed width is 1.5-1.7 m including ditches, and the bed height is 20-30 cm.
3. Planting time
The suitable sowing period for early-maturing oil-green choi sum is May to October, and the more suitable sowing period is August to October. In hot and rainy seasons, direct seeding is generally used, with a seeding rate of 400-500 g per mu; seedling raising and transplanting can also be used, with a transplanting seedling age of 15-18 days, when the seedlings have 3-4 leaves.
4. Covering with shade net
1. After sowing, cover with cool gauze to retain moisture, which has the effect of preventing high-temperature scorching, as well as rainstorm impact and soil crusting, and is beneficial for emergence, uniform emergence and full stands. After emergence, uncover the shade net promptly to prevent spindly growth. When planting in hot and rainy seasons, this avoids the adverse effects of unfavorable climate on choi sum growth.
2. Generally, after emergence, the shade net can be uncovered and raised 80-100 cm, and a small flat frame can be set up over the bed for heat-resistant and rainproof covering, with covering for 10-15 days being appropriate. If seedling raising and transplanting are used, covering for 5-7 days after transplanting is appropriate. It must not be covered for the entire growth period. When covering, a silver-gray shade net with a shading rate of 45% has a better effect.
3. When the true leaves of the seedlings unfold, it is necessary to promptly thin out overly dense seedlings, weak seedlings or diseased seedlings. At the 3-leaf stage, thin and fix the seedlings, with a plant spacing of about 13 cm. Before the plants bolt, it is necessary to thin out overly dense weak plants and inferior plants, which is beneficial for ventilation and light penetration, thicker and sturdier flowering stalks, and improved marketable rate and quality of the flowering stalks.
5. Fertilizer and water management
1. Early-maturing oil-green choi sum has a short growth period and fast growth speed, and requires sufficient base fertilizer. Generally, apply 1500-2000 kg of decomposed pig manure or 750 kg of chicken manure per mu, and 20-30 kg of compound fertilizer, fully mixed with the soil, and topdress promptly during the growth period.
2. In the early stage, topdressing is mainly with quick-acting nitrogen fertilizer, and in the middle and late stages it should be combined with increased application of phosphorus and potassium fertilizer, which is beneficial for improving the yield and quality of the flowering stalks. When fertilizing, avoid fertilizer falling on the flower buds, to avoid causing bud rot, and pay attention to watering to keep the bed surface moist.
3. Generally, when the first true leaf grows, apply 1 light application of thin manure water, or use 3-5 kg of urea per mu to promote seedling growth. At the 3-leaf stage, topdress in combination with thinning, using 1000-1500 kg of 20% human manure water per mu or 5 kg of urea, mixed with 10 kg of compound fertilizer.
4. Thereafter, about every 5-7 days, apply 1000-1500 kg of 30%-40% human manure water per mu or 10 kg of urea, mixed with 20 kg of compound fertilizer, 1 time. Stop fertilizing when the flowering stalks are harvested. About 3-4 topdressings are enough for the whole growth period.
6. Pest and disease control
1. Diseases mainly include anthracnose and soft rot. Anthracnose is a high-temperature and high-humidity disease. The pathogen mainly invades through wounds and spreads through rain and insects, occurring more from April to September each year.
2. In recent years it has occurred relatively commonly and has had a relatively large impact on choi sum production. In production, attention should be paid to choosing land with good drainage and irrigation and planting on high beds, carrying out crop rotation, doing a good job of field sanitation, removing diseased plant residues, and strengthening management.
3. In the early stage of disease occurrence, use 1000-fold Yeban Jing solution, 1000-1500-fold Shibaogong solution, 800-fold 50% carbendazim wettable powder, and 600-800-fold 75% thiophanate wettable powder alternately. For soft rot, use 1000-fold 70% dexon wettable powder, 500-fold Caifengning, and 3000-4000-fold 75% agricultural streptomycin for control.
4. Insect pests mainly include striped flea beetle, cabbage caterpillar, diamondback moth, and tobacco cutworm. At the seedling stage, attention should be paid to controlling striped flea beetle, and in the middle and late stages, attention should be paid to controlling cabbage caterpillar, diamondback moth, and tobacco cutworm.