Brassica oleraceae var. chinensis. Dark-green leaves are supported by thick, sweet, white stalks that are mild and juicy with a delicate flavour. Joi Choi pac choi seeds can be planted in cool soil and grow to 45cm (18") tall. Space plants 60cm (12") and be ready to harvest promptly. Cover with cloche if planting in very early spring, as plants will bolt if seedlings are exposed to cold temperatures. Sow numerous times at two to three week intervals to enjoy a long harvest window, and to avoid the whole crop maturing at once. The mature plant is somewhat cold-hardy; sow again in late summer for fall and winter harvests.
Matures in 50 days. (Hybrid seeds)
These cool-season vegetables are incredibly easy to grow and very tasty. The leaves can be used raw in salads, but the whole plant can be steamed or stir-fried. Both types require regular watering and a watchful grower – plant repeated short rows, and be sure to harvest them before they bolt. Follow along with this handy How to Grow Pac Choi and Choi sum Guide and grow delicious greens for stir-frying and steaming.
Brassica rapa chinensis
We Recommend: Mei Qing Choi (MU553). For growers particularly, this hybrid variety is surprisingly uniform in timing and growth. The plants are beautiful and upright with crisp stems and very good flavour. It works well in the home garden, but sow short rows repeatedly, or you’ll be overwhelmed by it all coming at once.
For Urban Gardeners: Toy Choi (MU522) works very well in containers and raised beds. It’s compact to the point of being cute, but tastes wonderful raw or cooked. Very nice, crunchy, succulent stems.
Season & Zone
Season: Cool season
Exposure: Full sun to partial shade
All are cool season plants that grow quickly and then bolt. Direct sow with frost protection (a cloche or heavy row cover) as early as February, or without protection from early March to late May. Sowing short rows every 2-3 weeks allows for a fairly constant harvest time. Sow again in August and September, and provide frost protection by the end of October.
Sow 3-4 seeds 5m-1cm (¼-½”) deep in each spot you want a plant to grow. Thin to the strongest plant at a spacing of 15-20cm (6-6″) between plants in rows 30-45cm (12-18″) apart.
Ideal pH: 6.0-6.8. 1 cup of complete organic fertilizer will provide sufficient nutrition to 3m (10′) of row. Choi Sum is harvested just before it flowers, so keep a close watch on each row. Pac Choi can be harvested at any stage, but if you want full-sized plants, watch for signs of bolting. Flower buds will appear at the centre of each plant, and a stem will form quickly as the plant turns from urn-shaped into a tall cone. Harvest as quickly as possible once flower buds are visible. Keep plants well-watered throughout their growth.
Use a sharp knife to cut the plants at ground level when they are ready to harvest. They will not grow back like some other crops, so plant several short rows every couple of weeks for a longer harvest.
In optimal conditions at least 70% of seeds will germinate. Usual seed life: 3 years. Per 100′ row: 260 seeds, per acre: 114M seeds.
Diseases & Pests
Slugs and woodlice (sow bugs) may nibble young seedlings. Keep the garden free from debris and excess water, where both of these pests like to go during the day. Protect plants from flea beetles and cabbage moths with lightweight row cover.