How to Grow Red Choi Sum
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Red Choi Sum
Brassica rapa subsp. parachinensis
vegetableRed Choi Sum is an Asian leafy green vegetable with red-tinged stems and small flower buds, prized for its tender, mildly sweet flavor. It's a quick-maturing brassica that produces edible stems, leaves, and unopened flower clusters. This cool-season crop is popular in stir-fries and Asian cuisine.
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Example Red Choi Sum timeline · Pittsburgh, PA (Zone 6b)
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Plant Red Choi Sum
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Red Choi Sum
Around May 27≈ 40 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Red Choi Sum dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; prefers cooler seasons (spring and fall)
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Seedling
2-3 weeksSmall cotyledons emerge with true leaves following within 1-2 weeks. Seedlings are delicate with green-red coloration.
Keep soil moist and provide bright light. Thin seedlings to proper spacing once true leaves appear. Protect from heavy wind.
Vegetative Growth
2-3 weeksPlant develops multiple true leaves with increasingly visible red coloration on stems. Leaf margins may be slightly serrated.
Maintain consistent moisture and temperature. Apply balanced fertilizer every 2-3 weeks. Monitor for pests weekly. Thin to final spacing if not already done.
Bolt Formation
1-2 weeksCentral stems elongate and small, unopened yellow flower buds form at the stem tips and leaf axils. Red coloration intensifies.
This is the prime harvest stage. Keep watering regularly. Harvest buds before flowers fully open. In warm weather, bolting accelerates.
Flowering
1-2 weeksYellow flowers open fully on the plant. Buds that weren't harvested develop into flowers; plant becomes less palatable.
If harvested before this stage, side shoots may develop for secondary harvest. Allow some plants to flower for seed production if desired.
Seed Development
3-4 weeksFlowers fade and seed pods (siliques) develop and mature. Plant becomes woody and inedible.
Only relevant if saving seed. Allow pods to dry on plant, then harvest and store seeds in cool, dry location.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Row covers on young plants; handpick caterpillars; spray with Bacillus thuringiensis (Bt); companion planting with dill and cilantro
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Strong spray of water; insecticidal soap; neem oil spray; encourage beneficial insects like ladybugs
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Row covers for seedlings; diatomaceous earth; neem oil; trap crops nearby
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Yellow sticky traps; reflective mulches; insecticidal soap; neem oil
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Soil pH management (raise to 7.2+); crop rotation (3-year minimum); resistant varieties; avoid waterlogging
Uses
Asian Stir-Fries
CulinaryRed Choi Sum is traditionally used in Chinese stir-fries and wok cooking. The tender stems, leaves, and unopened buds provide a mild, slightly sweet flavor and crisp texture that softens when briefly cooked. Commonly paired with garlic, ginger, soy sauce, and sesame oil. [source]
Fresh & Raw Salads
CulinaryYoung, tender leaves and stems can be eaten raw in salads or as a fresh green. They provide a mild flavor with minimal bitterness, making them suitable for mixed greens or Asian-style salads. [source]
Steaming & Blanching
CulinaryQuick steaming or blanching preserves the plant's delicate texture and slightly sweet flavor. Often served as a simple side dish with soy sauce, garlic, and oil. [source]
Nutritional & Antioxidant Benefits
MedicinalLike other brassicas, Red Choi Sum is rich in vitamins C and K, minerals, and glucosinolates—compounds with potential anti-cancer and anti-inflammatory properties. Supports overall health and immune function. [source]
Beneficial Insect Support
WildlifeAllowing some plants to flower provides nectar and pollen for bees, butterflies, and other pollinators. Flowers also attract beneficial insects that prey on garden pests. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest Red Choi Sum 40-50 days after planting when flower buds are still tightly closed but plants have reached 8-10 inches tall. Cut the main stem 1-2 inches above soil level with a sharp knife. Secondary shoots may develop for a second harvest. Harvest in early morning for best quality and crispness. Young tender leaves and stems are most palatable. Once flowers open, quality declines significantly.
Fun Facts
- 🌱 Red Choi Sum is a relatively recent development compared to traditional green Choi Sum, with the red coloration bred in for both visual appeal and potential additional antioxidants.
- 🌱 Unlike broccoli or cauliflower, Choi Sum is harvested for its leafy stems and unopened flower buds rather than large flower heads, making it one of the quickest-maturing brassicas (40-50 days).
- 🌱 In traditional Chinese cuisine, Choi Sum has been cultivated for centuries and is sometimes called 'Chinese broccoli' or 'Chinese flowering cabbage,' though it's distinct from both broccoli and cabbage.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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