Four-Season Planting Methods and Technical Points for Bok Choy

Bok choy is also called baby bok choy, rapeseed, or small rapeseed. It is a Brassica whose seeds can be pressed for oil, and it is also known by the alias rapeseed. It has two varieties, Brassica rapa and purple-stemmed tai cai. Its leaves have a powdery bloom, and its basal leaves are pinnately lobed, unlike baby bok choy. The planting season is generally from August to October, and it can be planted every year, but autumn and winter are best. In the north, it is suitable for indoor planting in winter.

Bok Choy Seedling Raising Methods

When temperatures are higher, direct sowing is suitable; when temperatures are lower, you can sow first and then transplant.

1. First water the potting soil thoroughly. Mix the seeds with fine soil, then broadcast them over the soil surface and cover lightly, just enough to cover the seeds; do not cover too thickly. You can use a sprayer to moisten the surface soil and keep it moist. They generally sprout in about 3-4 days, or about 1 week when temperatures are low. You can also use dibbling, with 2-3 seeds per hole and a spacing of about 3-5 cm. When temperatures are high, the spacing can be smaller; when temperatures are lower, the spacing should be slightly larger.

2. During the seedling stage, keep the soil moist. When temperatures are higher, water once each in the morning and evening. Two weeks after germination, apply 1 dose of dilute decomposed organic fertilizer along with watering.

3. When there are 4-5 true leaves, the plants can be transplanted and set out. The plant spacing depends on the size of the variety, generally about 15-20 cm. After planting, water thoroughly and provide slight shade; once established, manage normally. If transplanting is not needed, begin thinning the seedlings and pull out the larger seedlings. The principle of thinning is to make the seedlings more evenly distributed. You can thin several times until the spacing is appropriate, and after each thinning apply 1 dose of decomposed organic fertilizer.

Spring Cultivation Methods for Bok Choy

1. Variety: For bok choy cultivated in spring, choose varieties with strong winter hardiness so they are less likely to bolt. In the Shanghai area, varieties such as Sanyue Man, Siyue Man, and Wuyue Man are generally used.

2. Seedling raising: Make the seedling land into beds 2 m wide (including ditches), and use 1000 kg of decomposed organic fertilizer per mu. Sow from early to late October, using 0.3 kg of seed per mu. Sow evenly and firm the soil after sowing. After emergence, thin 2-3 times and apply appropriate topdressing. When the seedlings have 6-7 true leaves, they can be transplanted to the field.

3. Land preparation: After plowing the field, apply 50 kg per mu of special compound fertilizer for vegetables as a base fertilizer, and make beds 2.5 m wide (including ditches), ready for transplanting.

4. For greenhouse seedling raising, Sanyue Man is transplanted in late January, and Wuyue Man from early February to late March. The plant and row spacings are 10×15 cm for Sanyue Man, 15×15 cm for Siyue Man, and 15×20 cm for Wuyue Man.

5. Field management: After transplanting and establishment, apply topdressing once, using 5 kg of urea per mu. Apply a second time before the rows close, using 7.5 kg of urea per mu. In March, pay attention to preventing aphids.

6. Harvest: Open-field-grown Sanyue Man is harvested from late February to late March, greenhouse-grown Siyue Man from late March to early April, and Wuyue Man from late April to early May. Use a kitchen knife to remove the roots and market the cleaned vegetables.

Summer Cultivation Methods for Bok Choy

1. Variety: Choose varieties with strong heat tolerance and good quality for summer cultivation, such as Kangre Qing No. 3, Huawang, and 605.

2. Land preparation: Apply 40 kg per mu of special compound fertilizer for vegetables as a base fertilizer, and make beds 2 m wide (including ditches), with deep ditches and high beds to facilitate drainage and irrigation.

3. Sowing: Fire bok choy (bok choy cultivated in summer is called fire bok choy) is sown in batches from mid-June to early August, broadcast evenly. The seeding rate depends on the cultivation purpose. For cultivation as ji mao cai, use 2.5-3 kg of seed per mu. For “one sowing, three harvests,” use 1.2-1.5 kg of seed. For use as vegetable seedlings, use 1 kg of seed. Full-season coverage with insect-proof netting and shade netting can be used to achieve the goal of using less pesticide or no pesticide.

4. Field management: For fire bok choy, thin the seedlings once the cotyledons unfold, keeping a seedling spacing of 3 cm. Thin again after true leaves appear, with a seedling spacing of 12-14 cm. After each thinning, apply topdressing, using 6 kg per mu each time of special compound fertilizer for vegetables. Transplanted fire bok choy is generally sown in late July, with a seedling age of 25 days. Choose cool weather for transplanting, pull the seedlings in the afternoon, and set them out after 3 p.m., with a density of 12-14 cm square. Follow the principle of light and frequent watering, watering before 8 a.m. and after 5 p.m. to prevent rotting. Pay attention to controlling aphids, cabbage caterpillars, and diamondback moths.

Autumn Cultivation Methods for Bok Choy

1. Variety: Generally choose varieties with stronger resistance to viral disease, such as Ai Kang Qing and Xinchang Qing.

2. Seedling raising: Prepare the seedling land well, and sow in batches from early August to late September to raise seedlings, using 0.5-0.75 kg of seed per mu. After sowing, water 1-2 times daily. After emergence, thin 2-3 times, with a final seedling spacing of 3 cm square.

3. Land preparation is the same as for spring cultivation.

4. Transplanting: The transplanting time is generally from early September to early November, with a plant and row spacing of 20×25 cm. Water immediately after transplanting to settle the roots.

5. Field management: After establishment, apply the first topdressing, using 5 kg of urea per mu, and apply topdressing once more before the rows close. In drought, water or irrigate promptly, and pay attention to controlling aphids and viral disease.

6. Harvest: Depending on the transplanting period, the harvest period also differs. For September transplanting, harvest is possible in 25-30 days. For transplanting in early to mid-October, harvest in about 40 days; for transplanting from late October to early November, harvest in 45 days.

Winter Cultivation Methods for Bok Choy

1. Variety: Generally choose Dong Chang Qing and Eryue Man

2. Seedling raising: Sow from late September to early October to raise seedlings, using 0.4-0.75 g of seed per mu, and apply appropriate topdressing during the seedling stage.

3. Land preparation: Same as for spring cultivation.

4. Transplanting: The transplanting period for winter bok choy is from early November to the end of January the following year. Plant deeply and densely when transplanting. To avoid freezing injury, the usual plant and row spacing is 8×15-17 cm.

5. Field management: Basically the same as spring cultivation, with strengthened cold protection measures; non-woven floating row covers can be used.

6. Harvest: Winter-sown bok choy grows slowly and takes 80-90 days from transplanting to harvest, and can be appropriately advanced or delayed according to the market.