How to Grow Gai Lan (Chinese Broccoli): Sowing & Harvest

Gai lan — also called Chinese broccoli, kai-lan, or Chinese kale — is a fast, productive brassica grown for its thick, juicy flowering stems, tender leaves, and sweet, broccoli-like flower buds. Unlike heading broccoli, which makes one big crown and is largely done, gai lan is a cut-and-come-again crop: you harvest the main shoot and the plant pushes out a steady stream of side shoots for weeks. It is one of the most rewarding Asian greens for a home garden, ready in around 7-10 weeks, happy in beds or large containers, and superb stir-fried with garlic and oyster sauce. Like its cabbage-family cousins it is a cool-season plant that turns bitter and bolts in heat, so timing and steady growth are everything. This guide covers varieties, when to sow, spacing, feeding, beating the bolt, pests, and exactly when and how to cut for the longest harvest.

What Gai Lan Is and Which Variety to Grow

Gai lan (Brassica oleracea var. alboglabra) is the same species as broccoli, cabbage, and kale, but selected for thick edible stems and small clusters of white or yellow flower buds rather than a single dense head. You eat the whole thing — stem, leaves, and immature buds. Varieties differ mainly in maturity and stem thickness. ‘Green Lance’ and ‘Kailaan’ are reliable, fairly quick types; ‘Suiho’ and other early F1 hybrids size up fast and tolerate a little more warmth. There are also broccolini-style hybrids (gai lan crossed with broccoli, sold as “broccolini” or “Aspabroc”) that grow much like gai lan and give long, tender sprouting stems. For spring or marginal sowings, choose the quickest, most heat-tolerant variety you can find.

When to Plant

Gai lan grows best between about 55°F and 75°F. Like pak choi and other cool-season brassicas, it bolts and turns bitter in sustained heat and lengthening summer days, so aim for two windows.

Spring: Sow from around your last frost date once the soil has warmed to at least 50°F, through mid-spring. Avoid sowing into cold, wet soil — the cold-shock can push plants to bolt prematurely later. Spring crops race lengthening days, so pick fast varieties and harvest promptly.

Autumn: The more reliable season. Sow from roughly 8-10 weeks before your first fall frost as the summer heat breaks. Cooling temperatures and shortening days suit gai lan perfectly, and the stems are sweeter and slower to bolt. In mild-winter areas you can keep cropping through much of the cool season, and a cold frame or low tunnel extends it further. If you are matching crops to seasons across the garden, our overview of warm-season vs cool-season vegetables puts gai lan in context.

Sowing and Spacing

You can direct-sow gai lan or start it in modules and transplant — it handles transplanting better than pak choi, but young, undisturbed plants always bolt less. Sow seeds about a quarter to half an inch deep; they germinate in 5-10 days in warm soil. Thin or plant out to 6-10 inches apart with about 12-18 inches between rows. Closer spacing gives more, thinner stems; wider spacing gives fewer, thicker ones. Do not let seedlings crowd — competition checks growth and encourages bolting. Eat any thinnings as baby greens.

For a continuous supply, sow in succession — a short row every 2-3 weeks through each cool window. Because each plant keeps producing side shoots for weeks after the first cut, you need fewer successions than with a one-and-done crop, but staggering still smooths out the harvest and replaces plants as older ones tire.

Soil, Water, and Feeding

Gai lan is a hungry leafy brassica that rewards rich, fertile, moisture-retentive soil. Dig in a couple of inches of compost or well-rotted manure before planting. Steady, even moisture is critical: plants that dry out and then get flooded turn stringy, woody, and bolt-prone. Water deeply at the base, keep the soil evenly damp, and mulch to buffer moisture and soil temperature. In warm spells, light afternoon shade keeps plants cooler and delays bolting.

Because you harvest repeatedly, gai lan benefits from feeding. A nitrogen-leaning organic feed — diluted fish or seaweed solution every couple of weeks, or a side-dressing of a balanced fertilizer — keeps the plant pushing tender new shoots after each cut. Avoid drowning it in nitrogen, which makes soft growth that pests love. Healthy soil underpins all of this; if you are improving a new bed, our guide to clay vs sandy soil explains how to get the moisture-holding, free-draining texture brassicas prefer.

Beating the Bolt and the Heat

Gai lan naturally produces flower stalks — that is the part you eat — so the goal is not to stop flowering but to harvest the buds while they are sweet and tight, before heat forces them open and bitter. Bolting accelerates under sustained warmth, long days, and stress. To keep stems sweet and tender: sow in the cool seasons rather than into summer, keep the soil consistently moist, avoid crowding and transplant shock, and harvest promptly the moment buds form. In a hot spell, shade cloth and a deep mulch slow things down. If a plant races to full flower and yellow blooms in the heat, the stems will be tougher and more bitter — cut and use them quickly, or pull the plant and resow.

Pests and Problems

As a brassica, gai lan attracts the usual cabbage-family pests. Flea beetles riddle the leaves with tiny holes, worst in warm weather and on spring crops — cover the bed with insect-proof mesh from sowing to keep them off young plants. Cabbage white caterpillars chew leaves and hide among the buds; the same mesh excludes the egg-laying butterflies. Aphids cluster on shoot tips and in flower clusters — blast them off with water or treat early. Slugs and snails shelter at the plant base and shred young leaves. Rotate gai lan so it does not follow other brassicas in the same soil, which reduces clubroot and soil-borne pest pressure over time.

Harvesting Gai Lan for the Longest Crop

Timing the cut is the whole game. Harvest the main central stem when the flower buds have formed but before they open — the buds should still be tight, with maybe one or two flowers just starting. At that stage the stem is sweet and tender. Cut the stem about 4-6 inches long, slicing just above a leaf joint. That cut triggers the plant to send out side shoots from the leaf axils below, giving you a second, third, and fourth flush over the following weeks — true cut-and-come-again. Keep cutting those side shoots as they reach bud stage and the plant keeps producing.

Harvest in the cool of the morning when stems are crisp. The entire shoot is edible — peel any thick, tough lower stem if you like, but young gai lan rarely needs it. Use it within a few days, kept cool and slightly damp in the fridge, or blanch and freeze. A quick stir-fry or a brief steam with garlic, ginger, and oyster sauce is the classic preparation, and the slightly bitter-sweet flavor is exactly what makes gai lan worth growing. For more vegetable and leafy-green guides, browse the Plants & Flowers hub.