How do you grow Chinese broccoli hydroponically? Grow Chinese broccoli (gai lan) like a compact broccoli: start seeds about six weeks before transplanting, set plants 8–12 inches (20–30 cm) apart in buckets or a raft, and keep temperatures at 64–82°F (18–28°C). Harvest stalks before buds open, about 50–70 days from seed, then cut again as side shoots regrow.
Key takeaway: Chinese broccoli is a fast, heat-tolerant brassica grown for tender stalks, leaves and buds. Harvest before flowers open and leave lower leaf nodes so new shoots form.
| Gai lan need | Guideline | Source |
|---|---|---|
| Temperature range | 64–82°F (18–28°C) | NC State Extension |
| Seed start | About 6 weeks before planting | UC Master Gardeners |
| Spacing | 8–12 in (20–30 cm) | UC Master Gardeners |
| Days to harvest | 50–70 days | NC State Extension |
| Harvest stalk length | 7–9 in (18–23 cm) cut stems | Texas A&M AgriLife |
| Storage | 32–45°F (0–7°C), 85% humidity | Texas A&M AgriLife |
What Is Chinese Broccoli?
Chinese broccoli, also called gai lan, kai lan or Chinese kale, is a Brassica oleracea crop from China grown for its thick stems, glossy blue-green leaves and small flower buds. NC State Extension says plants grow 1–2 feet (30–60 cm) tall and taste like broccoli but stronger. It was crossed with broccoli to create broccolini.
UC Master Gardeners of Santa Clara County note that it produces a smaller head than broccoli, and that buds, shoots and succulent stems are all eaten. Compare it with hydroponic kale or hydroponic broccoli.
What Temperature Does Gai Lan Need?
Gai lan tolerates more heat than most brassicas. NC State Extension says it withstands summer heat better than other kales and grows best at 64–82°F (18–28°C). Texas A&M AgriLife adds that it grows best in the cool weather of fall, winter and spring but tolerates warm temperatures into summer. Flavor improves in cooler weather.
UC Master Gardeners warn that spring plants are more likely to bolt due to warm weather and longer days, while fall plants produce for longer. Indoors, steady temperatures keep shoots tender. See our heat stress and cold stress guide.
How Do You Start Chinese Broccoli Seeds?
Start Chinese broccoli seeds about six weeks before you plan to transplant, as UC Master Gardeners suggest. Sow into rockwool or coco plugs, keep them moist and warm until sprouts appear, then give strong light. NC State notes damping off is a serious seedling disease, so use clean trays and avoid soggy media.
- Soak plugs and drain excess water.
- Sow 1–2 seeds per plug, about 1/4 in (6 mm) deep.
- Keep plugs at room temperature until seedlings emerge.
- Move seedlings under bright light and run a gentle fan.
- Thin to one seedling and transplant at about 6 weeks.
Damping off and weak sprouts are covered in hydroponic seeds not germinating.
Which Hydroponic System Suits Gai Lan?
Gai lan suits deep water culture, Dutch buckets and wide NFT channels because plants stay 1–2 feet (30–60 cm) tall. UC Master Gardeners recommend 8–12 inches (20–30 cm) between plants. A raft with holes on 10-inch (25 cm) centers or a row of buckets works well. Use a complete vegetative nutrient and keep the root zone well aerated.
- DWC raft or tote: simple and stable; see deep water culture for beginners.
- Dutch buckets: good for larger plants; see Dutch bucket hydroponics.
- Nutrients: Texas A&M notes well-fertilized plants develop thick stems 1/2–3/4 in (13–19 mm) wide.
When and How Do You Harvest Chinese Broccoli?
Harvest Chinese broccoli just before the flower buds open. UC Master Gardeners say to cut flowering stalks about 6–8 inches (15–20 cm) from the top, leaving one or two leaf nodes so side shoots develop. Texas A&M recommends cut stems 7–9 inches (18–23 cm) long with terminal leaves intact. NC State says first harvest comes in 50–70 days.
Pick on time. NC State warns stems become woody if left too long, and buds turn into white or yellow flowers. Regular cutting keeps tender new shoots coming for several harvests.
Can You Harvest Gai Lan More Than Once?
Yes. UC Master Gardeners say you can harvest it multiple times because new shoots grow from lower leaf nodes. Leave at least one or two nodes on each stem after cutting. In hydroponics, keep nutrients and light steady between cuts so plants regrow quickly. Each round of shoots tends to be thinner than the first main stalk.
Store bunches at 32–45°F (0–7°C) with 85% relative humidity, as Texas A&M advises, and use them within days for the best texture.
What Pests Attack Chinese Broccoli?
NC State Extension lists flea beetles, diamondback moth, borers and cabbage looper as main pests, with aphids at a lower level. Damping off is the most serious disease, and good drainage helps prevent it. Indoors, aphids and caterpillars are most common. Check leaf undersides weekly and remove caterpillars by hand.
NC State notes gai lan may cause contact dermatitis in some people, so wear gloves if your skin is sensitive. For aphids, see hydroponic pests: aphids and mites.
FAQ About Gai Lan
Is gai lan the same as Chinese broccoli?
Yes. Gai lan, kai lan and Chinese kale are common names for the same crop.
How long does gai lan take to grow?
About 50–70 days from seed, per NC State Extension.
Can you eat gai lan flowers?
Yes. NC State says flower stalks, leaves and buds are eaten raw or cooked.
Does gai lan regrow after cutting?
Yes, from lower leaf nodes left on the stem.
Is gai lan heat tolerant?
More than most brassicas; it grows best at 64–82°F (18–28°C).
Sources
- NC State Extension Gardener Plant Toolbox — Brassica oleracea Kai Lan & Chinese Kale Group
- UC Master Gardeners of Santa Clara County — Gailon
- Texas A&M AgriLife Extension — Chinese Kale (Kailaan)
- Photo credits (Wikimedia Commons, edited with titles): Gai lan by Nthaci (CC BY-SA 4.0); Starr-150326-0887-Brassica rapa var chinensis-seedlings in Hydroponics greenhouse-Town Sand Island-Midway Atoll (24971491710) by Forest and Kim Starr (CC BY 3.0 us); Ornamental-kale Nagano by MaedaAkihiko (CC BY-SA 4.0); Deepwater Aquaponics Floating Rafts Growing Lettuce, Basil and Arugula by Alabama Extension (CC0)