Choy Sum Seeds — Brassica rapa subsp. parachinensis / Cải Ngọt / Cai Xin / Yu Choy, Chinese Flowering Cabbage Seeds for Stir-Fries, Soups & Container Gardens, 2 Pack x 3000 Seeds

Technical Specifications

About Choy Sum — Cải Ngọt / Cài Xīn

Choy Sum (Brassica rapa subsp. parachinensis) is one of the most widely grown and eaten Asian greens in Vietnamese and Chinese home cooking. Unlike bok choy, which is grown primarily for its thick white stalks and broad leaves, choy sum is grown for its slender, tender flowering stems, leaves, and yellow flower buds — all of which are harvested together just as the buds begin to form. The flavor is mild, slightly sweet, and gently mustardy — more delicate than mustard greens and less bitter than many other brassicas.

In Vietnamese cooking, cải ngọt (literally “sweet cabbage”) is an everyday vegetable — stir-fried with garlic, added to soups and noodle broths, or blanched and served with oyster sauce. In Cantonese and Chinese cooking, choy sum or cài xīn is one of the most common restaurant greens — the classic blanched-with-oyster-sauce preparation (háo yóu cài xīn, 豪油菜心) is a staple of Cantonese cuisine.

The Gunsho variety is selected for better heat tolerance than standard choy sum types, making it more suitable for warm-season growing and a wider range of climates. It is one of the fastest-growing vegetables you can grow from seed — 25–45 days from sowing to first harvest, making it ideal for succession planting and continuous supply.

• Mild, slightly sweet, gently mustardy flavor — more delicate than mustard greens
• Entire plant is edible: tender stems, leaves, and yellow flower buds
• Known as Cải Ngọt in Vietnamese, Choy Sum in Cantonese, Cài Xīn (菜心) in Mandarin
• 25–45 days to harvest — one of the fastest-growing Asian greens
• Gunsho variety: better heat tolerance than standard choy sum types
• Cut-and-come-again — often regrows for 1–2 additional cuttings after the main harvest

Master Sowing & Growing Guide

Step 1 — Timing & Season Planning

Choy Sum is a cool-season crop that performs best in spring and fall. The Gunsho variety handles heat better than standard types, extending the growing window.

• Midwest / Northeast: Spring (after last frost, mid-April–May) and fall (late summer sowing for September–October harvest).
• South / Southwest: Fall through early spring (October–March). Provide afternoon shade in summer if growing in heat.
• West Coast / Pacific Northwest: Nearly year-round in mild climates; avoid peak summer heat.

Succession sowing: Sow small batches every 2–3 weeks for a continuous supply of fresh stems rather than a single large harvest.

Step 2 — Soil & Location

Choose a site with full sun to part shade and fertile, moist, well-drained soil. Amend with compost before sowing. For containers, use a good-quality potting mix in a pot at least 20–25 cm (8–10 inches) deep — 5–10 gallon containers work well for a productive planting.

Step 3 — Sowing

Sow seeds 5–10 mm (1/4 inch) deep directly into prepared soil or containers. No soaking needed. Space seeds 5 cm (2 inches) apart, then thin to 10–15 cm (4–6 inches) apart when seedlings are 5 cm tall. Thinnings are edible — use them in salads or soups. Germination is fast — expect seedlings in 4–10 days at 15–24°C (60–75°F).

Step 4 — Watering & Feeding

Keep soil consistently moist throughout the growing season. Drought stress triggers premature bolting and tougher stems. In containers, check moisture daily in warm weather. Feed with a balanced liquid fertilizer every 2–3 weeks to support fast, tender growth. In hot weather above 30°C (85°F), provide afternoon shade to slow bolting.

Step 5 — Harvesting

Harvest timing is key: Cut the main flowering stem when the buds are fully formed but before the yellow flowers fully open — typically when the plant is 20–40 cm (8–15 inches) tall. This is the peak moment for tender stems and sweet flavor. Once flowers open fully, stems become tougher and flavor declines.

How to harvest: Cut the main stem and top portion (stems, leaves, and buds) with a sharp knife or scissors, leaving 5–10 cm of stem at the base. The plant often regrows side shoots for 1–2 additional cuttings. The more you harvest, the more it produces.

Whole plant harvest: For a single large harvest, cut the entire plant at the base when buds form.

Kitchen Applications

• Stir-fry with garlic (suàn róng cài xīn / xào tỏi cải ngọt): High heat, garlic, oyster sauce, and a splash of soy — the classic preparation, ready in under 5 minutes.
• Blanched with oyster sauce (háo yóu cài xīn): Quick boil or steam, then drizzle with oyster sauce and fried shallots — a Cantonese restaurant staple.
• Soups & noodle broths: Add stems and leaves at the end of cooking for crisp texture in wonton soup, pho, or ramen.
• Canh cải ngọt (Vietnamese sweet cabbage soup): Simmered in a light pork or shrimp broth — a simple Vietnamese everyday soup.
• Steamed: Steamed whole stems and served with a dipping sauce or drizzle.
• Raw in salads: Young leaves and tender stems can be used raw in Asian-style salads.

Common Growing Problems & Solutions

Frequently Asked Questions

What is the difference between Choy Sum and Bok Choy?

Choy Sum (Brassica rapa subsp. parachinensis) and bok choy (Brassica rapa subsp. chinensis) are related but different vegetables. Choy Sum is grown for its slender flowering stems, leaves, and yellow flower buds — harvested just as the buds form. Bok choy is grown for its thick white stalks and broad leaves, harvested before flowering. Choy Sum has a milder, sweeter flavor; bok choy has a more substantial, crunchy texture.

What is Cải Ngọt?

Cải ngọt is the Vietnamese name for choy sum — literally “sweet cabbage.” It is one of the most common everyday vegetables in Vietnamese home cooking, used in soups, stir-fries, and blanched preparations. It is the same plant as Cantonese choy sum / choi sum and Mandarin cài xīn (菜心).

When exactly should I harvest Choy Sum?

Harvest when the flower buds are fully formed but before the yellow flowers fully open — this is the peak moment for tender stems and sweet flavor. Once flowers open fully, stems become tougher and the flavor declines. Check plants daily once they reach 20–30 cm tall.

Can I grow Choy Sum in containers?

Yes. Choy Sum grows well in containers at least 20–25 cm (8–10 inches) deep. A 5–10 gallon pot can support several plants for a productive harvest. Water consistently — containers dry out faster than garden beds. Move containers to shade during heat waves to slow bolting.

How many seeds are included?

2 packs x 3000 seeds = 6000 seeds total.

Storage & Quality Assurance

• Store unused seeds in a cool, dry, dark place in a sealed container or the original packet.
• Optimal storage temperature: below 15°C (60°F) with low humidity; refrigerator storage extends viability.
• Brassica seeds remain viable for 3–5 years when stored correctly.
• This is a seed product for planting — not a ready-to-eat vegetable, dried green, or live plant.
• Germination rates and stem quality are influenced by season, temperature, moisture, and growing conditions. Results vary by grower and location.