Choy sum (Brassica rapa var. parachinensis)

Choy sum

Choy sum is a popular plant in Asian vegetable gardens, and is also common in the United States. Unlike some species in the genus, choy sum is cultivated specifically for garden use, where the hardy plant can even grow in the snow. The cultivar can also grow in poor soil conditions, while its parent plants would struggle.

Scientific classification

Mustards, capers, and allies

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Annual

Lifespan

Herb

Plant Type

Summer

Bloom Time

20 cm to 50 cm

Plant Height

20 cm to 30 cm

Spread

Green

Leaf Color

Winter dormancy

Dormancy

Deciduous

Leaf type

20 - 35 ℃

Ideal Temperature

Images of Choy sum

Care Guide for Choy sum

Every week

Water

Full sun

Sunlight

20 - 35 ℃

Ideal Temperature

Garden Soil

Soil Type

Water: Choy sum prefers consistently moist soil, requiring weekly watering to maintain optimal moisture without waterlogging. It thrives outdoors, benefiting from mulching to retain moisture, particularly during the active growing season when its water demand is highest.

Fertilize: Brassicas require high nutrient levels, particularly nitrogen, which should be four times that of other macronutrients. Use manure or compost in fall, with general-purpose fertilizers in spring. Application methods, whether broadcast or banded, depend on location and climate. Adding lime-containing fertilizers helps maintain optimal soil pH for choy sum.

Pruning: Choy sum is a fast-growing leafy vegetable with edible stems and leaves. Prune in early to mid-spring to remove weak shoots, promoting robust growth. Regularly pinch tips for bushiness and harvest. Proper pruning improves air circulation and reduces disease risk. Use clean, sharp tools for best results.

Propagation: Choy sum can be efficiently propagated by sowing in well-draining, compost-enriched soil. Keep the soil consistently moist and space seeds adequately for growth. Germination thrives in full sunlight, and thinning seedlings prevents overcrowding, optimizing growth and yield.

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