How to Grow Napa Cabbage? A Summary of Efficient Spring and Autumn Cultivation Techniques
Napa cabbage, of the genus Brassica in the family Brassicaceae, originated in northern China and is a traditional Chinese vegetable. Napa cabbage contains B vitamins, vitamin C, calcium, iron, and phosphorus, and its content of the trace element zinc is also very high. The places of origin of napa cabbage are the Mediterranean coast and China. The area south of the Yangtze River is the main production region, with a planting area accounting for 40%-60% of the autumn, winter, and spring vegetable sowing area. How to grow napa cabbage? A summary of efficient spring and autumn cabbage cultivation techniques.
I. Spring Napa Cabbage Cultivation Techniques
1. Choosing Varieties
For spring napa cabbage cultivation, you must choose early-maturing varieties with strong winter hardiness, tolerance to low temperatures, and a short growing period. Suitable large-head spring cabbage varieties include “Yuyi Yingchun” and “Shengchun”; small-head cabbage varieties include “Jin Linglong” and “Yu Linglong” baby cabbage.
2. Raising Seedlings
In North China, for cultivation in plastic tunnels or small arched sheds covered with straw mats, the seedling-raising time is mid-to-late February; for open-field cultivation with plastic mulch, seedlings should be raised in small arched sheds in early-to-mid March. Either broadcast sowing for seedlings or plug trays or nutrient pots can be used for raising seedlings, with a high transplant survival rate. For broadcast-sown seedlings, thin them promptly at the 1-leaf-1-heart stage, keeping a spacing of 2-3 cm. Transplant at the 3-4 true-leaf stage. Napa cabbage generally passes through vernalization after 10-25 days at 2°C-13°C, forming flower buds and then bolting and flowering, so the minimum temperature in the spring seedbed should be kept above 15°C, and after transplanting, low temperatures below 10°C should be avoided as much as possible.
3. Fertilizing and Preparing the Soil
Choose a plot where no cruciferous crops were previously grown, and plow it before winter to freeze and thaw the soil and mature it. After the soil thaws in early spring, apply 5000 kg of decomposed organic fertilizer per mu, and 30-50 kg of superphosphate or compound fertilizer, then shallow-plow to mix the soil and fertilizer evenly. After leveling the land, make low beds 1 m wide. Because there is little rain in early spring, low beds can maintain soil temperature, promote root development, accelerate vegetative growth, and at the same time facilitate watering and management.
4. Transplanting
Transplant when the soil temperature below 10 cm in the planting field is stable above 10°C. For large-head varieties, plant 2 rows per bed, with a plant-to-row spacing of 35-40 cm × 50 cm; “Jin Linglong” is a small-head variety, plant 3 rows per bed, with a plant-to-row spacing of 30 cm × 40 cm, about 5500 plants per mu. For “Yu Linglong” baby cabbage, the plant-to-row spacing is 25 cm × 25-30 cm, with 8000-10000 plants per mu.
5. Field Management
After transplanting spring cabbage, water promptly with a small amount of water; 2-3 days later, water again to help the seedlings recover, also with a small amount of water. Then cultivate to conserve soil moisture, to prevent the soil temperature from dropping too quickly and affecting seedling recovery. Later, as the air and soil temperatures rise, appropriately increase the frequency and amount of watering to meet the water needs of napa cabbage during head formation. Spring cabbage has no obvious seedling-hardening period, so in addition to applying sufficient base fertilizer before transplanting, topdressing should also be applied appropriately early. Apply one topdressing after transplanting and seedling recovery, flushing 10 kg of urea per mu with water; before head formation, apply 20-25 kg of compound fertilizer per mu to facilitate smooth head formation and expansion. During the seedling stage and head formation stage, apply “Yunda 120 + Yuyi potassium dihydrogen phosphate”, which can promote leaf growth and early head formation, with an obvious yield-increasing effect. Throughout the entire growth process, the maximum temperature inside the shed should be appropriately adjusted according to temperature changes and must not exceed 25°C.
II. Autumn Napa Cabbage Cultivation Techniques
1. Choosing Excellent Varieties
There are many napa cabbage varieties, which can be divided into three basic ecotypes: cylindrical, round-headed, and oval. However, due to the growing season, disease-resistant, cold-tolerant, high-yielding, and storage-tolerant mid-to-late-maturing varieties must be chosen. The main excellent varieties include: Lubai No. 3, Shandong No. 2, Shandong No. 5, Fengkang 85, etc.
2. Sowing Time
Generally, sowing 3-5 days around the start of autumn is appropriate; in years with high temperatures, it can be postponed to mid-August. Disease-resistant late-maturing varieties with a long growing period can be sown appropriately earlier, while mid-maturing varieties with a short growing period can be sown a few days later.
3. Preparatory Work Before Sowing
Napa cabbage cannot be continuously cropped, nor can it be rotated with other cruciferous vegetables; this is one of the important measures for preventing pests and diseases. Make furrows 5-10 cm deep, first water along the furrows, and after the water seeps in, evenly scatter the seeds in the furrows, and cover with 0.8-1 cm of fine soil. The seeding rate is about 0.5 kg per mu. For directly sown napa cabbage, after the young sprouts emerge, adopt the measure of frequent light watering to keep the ground moist and lower the surface soil temperature. In the absence of rain, generally water once on the day of sowing or the next day, making sure to wet the ridge surface thoroughly, and water a second time on the third day after sowing to promote the emergence of most young sprouts.
Seedling stage management. This refers to management from the emergence of young sprouts to the rosette stage. At this time, thin the seedlings promptly, and at the 2-3 true-leaf or 4-5 true-leaf stage, thin once each, and remove weeds, diseased seedlings, and weak seedlings. At the 6 true-leaf (rosette) stage, final thinning is done, and cultivation should be timely to avoid damaging roots and leaves. Cultivation should be shallow rather than deep. For directly sown plants, transplant generally at the 5-6 true-leaf stage.
Transplanting and planting out. The seedling age is generally 15-20 days, and when the seedlings have 5-6 true leaves, it is the best time for transplanting. Transplanting is best done in the afternoon. Determine the appropriate density according to the characteristics of the variety. Water immediately after planting. Thereafter, water once each morning and evening every day for 3-4 consecutive days to help the seedlings recover and survive.
4. Fertilizer and Water Management
Topdressing. Napa cabbage has high yield and high fertilizer demand. On the basis of applying sufficient base fertilizer, topdressing should not be delayed. Topdressing should be determined according to different growth stages and seedling conditions. Generally no topdressing is applied at the seedling stage. If the base fertilizer is insufficient, the first application can be at the 3-4 true-leaf stage, applying 10 kg of ammonium sulfate per mu, broadcast on both sides of the seedlings, and watered immediately, called the “seedling-promoting fertilizer”; the second application is after final thinning or after seedling transplanting, applying 15-20 kg of ammonium sulfate per mu, placed in furrows opened on both sides of the ridge, called the “plant-developing fertilizer”; the third application is at the rosette stage, applying 25-30 kg of ammonium sulfate and 10-15 kg of superphosphate per mu, placing the fertilizer into furrows or holes, then slightly earthing up and supporting the ridge, then watering, called the “major topdressing”; the fourth application is in the middle of head formation, applying 15-20 kg of ammonium sulfate per mu, which can be flushed with water, called the “heart-filling fertilizer”.
Watering. From the rosette stage to the heading stage, the temperature gradually drops and the weather is mild; during this period, water appropriately, and at the end of the rosette stage, control water appropriately for several days, then water after the third topdressing. After napa cabbage enters the head formation stage, it needs the most water; therefore, as soon as the seedling-hardening period ends, water thoroughly once. Then, after 2-3 days, water a second time. This one is very important; if the soil cracks at this time, the lateral roots will break and the fine roots will die, affecting head formation. Thereafter, generally water once every 5-6 days to keep the soil moist.
5. Binding Leaves and Harvesting
In the late growth period of napa cabbage, the weather is changeable and the temperature gradually drops. To prevent frost damage, bind promptly. Generally 10-15 days before harvest, stop watering, lift the rosette leaves, wrap them around the head, and then bind the leaves with soaked sweet potato vines or cereal straw. This makes the head firmer and allows it to continue growing. 2-3 days before Light Snow, harvest promptly, and dry in the field; once the outer leaves wilt, they can be stored.