A practical vegetable garden series
Grow Hon Tsai Tai, the purple-stemmed choy sum, for tender leaves, stems and flower buds.
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GROW WITH US Hon Tsai Tai is a quick, colourful choy sum with purple stems, tender leaves and edible flower buds. Sow in spring or late summer, keep the soil moist and use fine mesh to protect young plants. Cut the shoots while the buds are plump and still closed. |
Written for home gardeners in Hungary
CHAPTER WELCOME
Your choy sum season starts here
This book follows the whole journey: seed → seedling → garden → care → harvest → kitchen → next season.
This guide is about Hon Tsai Tai, a purple-stemmed kind of choy sum grown for its tender leaves, shoots and unopened flower buds. It is a quick-growing member of the cabbage family, but it does not form a head like Chinese cabbage or a broad rosette like pak choi. You can eat the whole young shoot, and its small yellow flowers are edible too.
In Hungary, grow choy sum in the cooler parts of the season: sow in early spring or again in late summer for an autumn harvest. Near Győr, spring sowing can begin when the soil is workable, with fleece ready for a hard cold snap. Avoid the hottest, driest weeks if you can. Keep the bed evenly moist and pick the purple shoots while their flower buds are plump but still closed.
Our Hungarian calendar
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February–March |
Start a few seeds under cover for an early crop. |
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March–April |
Sow outdoors when the soil is workable; cover if frost is hard. |
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May–June |
Pick spring shoots before hot weather makes them tough. |
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Late July–August |
Sow again for tender autumn stems. |
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September–October |
Harvest shoots with plump, unopened buds. |
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Before hard frost |
Pick remaining tender stems and clear the bed. |
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WHAT I WOULD DO I would sow a short row in spring, then another in late July for autumn. I would keep both sowings evenly watered and pick the stems while their flower buds are still closed. |
The rule for this series: dates guide us, but the plant and the weather make the final decision.
CHAPTER 1
Meet Choy Sum
Hon Tsai Tai makes purple stems, green leaves and edible flower buds.
Choy sum, also called Chinese flowering cabbage or cai xin, is a quick-growing Asian brassica. Hon Tsai Tai is the familiar purple-stemmed form, with green leaves and slender shoots that may grow more purple in cool weather. The leaves, juicy stems and unopened flower buds are all edible. Unlike pak choi, it is grown for flowering shoots rather than a compact rosette; unlike Chinese cabbage, it does not form a head.
Choy sum or other Asian greens?
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Choy sum |
Slender leafy shoots with edible stems and flower buds. |
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Pak choi |
Broad leaves in a compact rosette with thick stems. |
Three brassicas, three different harvests
· Choy sum: tender stems, leaves and flower buds on slender shoots.
· Pak choi: broad, spoon-shaped leaves on thick, crisp stems.
· Chinese cabbage: forms a dense head of overlapping leaves.
· Hon Tsai Tai: purple stems and green leaves; colour deepens in cool weather.
· Harvest the buds: pick when they are developed but still closed.
· Cool-season crop: mild weather and steady moisture give the best shoots.
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GOOD TO KNOW Hon Tsai Tai is the purple-stemmed form of choy sum. Its leaves, stems and unopened buds are all edible, and the purple colour often deepens in cool weather. |
CHAPTER 2
Choose Your Choy Sum
Plan a cool-weather sowing and decide whether you want slender shoots or larger flowering stems.
Ask yourself five questions
1. Would I like to grow purple-stemmed Hon Tsai Tai?
2. Can I sow in spring or late summer rather than the hottest weeks?
3. Can I keep the shallow-rooted plants evenly watered?
4. Will I cover young plants against flea beetles and caterpillars?
5. Can I harvest the shoots while their flower buds are still closed?
A beginner-friendly first planting
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Sow for mild weather |
Spring and late summer give tender growth. |
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Keep it growing |
Steady moisture helps prevent tough, stressed shoots. |
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Cover young plants |
Fine mesh deters flea beetles and caterpillars. |
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Pick the buds |
Harvest when they are plump but still closed. |
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A COMMON MISTAKE Sowing a whole packet in one go. Choy sum grows quickly, so sow a short row every few weeks for a steadier supply. |
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TRY THIS Plant Hon Tsai Tai where its purple stems can catch the light. Cool autumn nights can deepen their colour before you harvest. |
CHAPTER 3
Let’s Sow
Choy sum grows quickly from seed and is easiest to manage in small, repeated sowings. It prefers cool to mild weather, fertile soil and steady moisture. Sow directly in a prepared bed or start a few seeds in modules for an early crop. For tender shoots, thin plants close enough to support one another but leave room for air and growth.
When to sow in Hungary
For a spring crop, sow under cover in February or March, or directly outdoors from March into April once the soil can be worked. Sow again from late July into August for autumn shoots. Make a shallow drill about 0.5–0.6 cm deep, with rows 25–30 cm apart. Sow thinly, cover lightly and water gently. Thin to about 10–15 cm for slender shoots, or 20 cm for larger plants. In hot weather, give young seedlings light shade and water regularly.
What you need
· Hon Tsai Tai or choy sum seeds
· A hand fork or small rake for preparing the bed
· A watering can with a fine rose and a clear label
· Fine insect mesh to protect young brassica leaves
· Fertile soil that holds moisture but drains freely
Sowing, step by step
1. Remove weeds and loosen the soil; mix in mature compost if the bed needs it.
2. Make a shallow drill about 0.5–0.6 cm deep, with rows 25–30 cm apart.
3. Sow seeds thinly, cover lightly and water gently.
4. Label the variety and date; keep the soil evenly moist.
5. Thin seedlings to 10–15 cm for slender shoots or about 20 cm for larger plants.
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DON’T PANIC A flower stem is normal on choy sum. Pick it when the buds are full and closed; you can eat the tender stem, leaves and buds together. |
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A COMMON MISTAKE Letting the bed dry out as stems form. Shallow roots need steady moisture to keep shoots crisp and tender. |
CHAPTER 4
Seedling School
Choy sum seedlings appear quickly in mild weather. Keep them growing steadily, then thin or transplant them before the roots become crowded.
Thin for the harvest you want
When seedlings have several true leaves, thin them gradually. Leave about 10–15 cm for slender shoots or close rows of young greens, and about 20 cm for larger flowering stems. Use the thinnings in a salad or stir-fry. If you started in modules, move seedlings while they are young and handle the roots gently.
Why are flower buds appearing already?
Flowering is part of the choy sum harvest: the tender shoot and its unopened buds are the prize. Very hot, dry weather or a sudden check to growth can make plants rush into flower before they have made a useful stem. Sow in mild weather, keep the soil moist and harvest promptly when the buds are plump but closed.
Water while they settle
Keep the soil moist from sowing until the seedlings are established. Choy sum has shallow roots and grows quickly, so a dry spell can make young plants stop growing or turn tough. Water the bed in the morning during warm weather. Pots dry more quickly than garden soil and need frequent checks.
Feeding
Choy sum grows best in fertile soil. Work mature compost into the bed before sowing. If plants are pale or slow, check moisture and weeds before adding feed. Container plants may benefit from a balanced liquid feed during active growth, following the label.
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WHAT I WOULD DO I would sow in a cool window, water in the morning and keep fine mesh over the bed from the day the seedlings appear. |
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DON’T PANIC A few yellow flowers are edible. If the buds open before you pick, harvest the stem promptly and use it cooked. |
CHAPTER 5
Ready for the Real World
Choy sum can be sown directly or moved outdoors as a young seedling. Choose a mild spell and help the crop keep growing without a check.
Before planting: check the plants and the bed
1. Choose sturdy seedlings with several true leaves and healthy centres.
2. Water module-grown seedlings before planting.
3. Harden plants off gradually in a sheltered place for about a week.
4. Prepare a fertile bed that holds moisture and drains well.
5. Plant at the same depth as in the module; water in gently.
When is it ready in Hungary?
For spring shoots, sow under cover in February or March and plant out when seedlings are sturdy and the soil is workable. Direct sowing from March into April is also possible; protect young plants with fleece if a hard frost is forecast. For autumn, sow from late July into August so the crop develops as nights cool. In colder parts of Hungary, sow toward the earlier end of that window.
Around Győr, warm, dry spells can make choy sum bolt quickly, so keep spring and summer sowings moist and consider light afternoon shade. Fine mesh helps stop flea beetles and cabbage caterpillars before they damage the leaves. Harvest the shoots in late spring or autumn when the flower buds are well formed but still closed. A light frost can deepen the purple colour, but protect tender plants from a hard freeze.
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A COMMON MISTAKE Waiting for large, thick stems. Choy sum is tenderest when the shoots are young and the buds have not opened. |
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GOOD TO KNOW Harvest usually begins about 30–50 days after sowing, depending on the variety and weather. |
CHAPTER 6
Give Them a Good Home
Mild weather, fertile soil and steady moisture help choy sum make juicy stems and tender buds.
The right place
Choose a sunny bed in spring or autumn. During warmer weather, light afternoon shade can help the plants stay tender. Choy sum likes fertile soil that holds moisture without becoming waterlogged. Add mature compost before sowing and keep weeds down. Rotate it away from beds used recently for cabbage, broccoli, cauliflower and other brassicas.
Spacing
Space rows about 25–30 cm apart. Leave 10–15 cm between plants for slender shoots or about 20 cm for larger stems. Closer sowings can be harvested young, while wider spacing gives individual plants room to branch. Follow the seed packet if it gives a different spacing for your variety.
Planting day
1. Water seedlings and prepare a moist, weed-free bed.
2. Make a hole just large enough for the root ball.
3. Set the plant at the same depth it grew in its module.
4. Firm gently and water around each seedling.
5. Cover the crop with fine mesh if pests are a problem.
Growing in pots
Choy sum is well suited to a wide trough or container at least 20 cm deep, with drainage holes and fresh potting mix. Sow a few seeds in a row and thin to about 10–15 cm apart for slender shoots. Place the pot in sun during cool weather or light shade in warm weather. Check the compost often so it stays moist but never waterlogged.
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TRY THIS Stir-fry Hon Tsai Tai with garlic: give the sliced stems a head start, then add the leaves and buds for the final minute. |
CHAPTER 7
Water, Feed & Keep Them Growing
Steady moisture and quick, even growth help choy sum stay tender until harvest.
Watering
Keep the soil evenly moist, especially while plants are young and as stems lengthen. Choy sum can become tough if growth stalls in hot, dry weather. Water deeply in the morning and check containers often. A light mulch can help the bed hold moisture through a warm spell, but avoid keeping the crown constantly wet.
Mulch
For larger plants, add a thin layer of mature compost around them once they are established. This helps conserve moisture and suppress weeds. Keep mulch away from the central stems so they do not stay damp. Mulching is not essential for a closely sown crop harvested young.
Feeding
A fertile bed prepared with compost usually provides enough nutrients for this quick crop. If growth is slow, first check watering, spacing and weeds. Choy sum in containers may benefit from an occasional balanced liquid feed; use it according to the label and avoid overfeeding.
Keep plants healthy
Use fine insect mesh to keep flea beetles, caterpillars and cabbage butterflies away from young leaves. Check beneath leaves for eggs and caterpillars, and look for slugs after rain. Remove badly damaged plants and avoid growing choy sum in the same brassica bed year after year. Water the soil rather than the leaves to reduce disease.
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WHAT I WOULD DO I would sow short rows a few weeks apart so the shoots mature in turns instead of all at once. |
CHAPTER 8
Flower Buds, Stems & “What Is That?”
Choy sum is harvested for its leafy shoots and flower buds. The buds should be plump and formed, but not yet open.
Why has my choy sum started flowering?
A central shoot with small yellow buds is normal and is exactly what choy sum is grown for. Pick the stems when the buds are full but still closed. If the plant races into flower while its shoots are still thin, warm weather, dry soil or a check to growth may be to blame. Sow in a cooler window, keep watering steady and harvest promptly.
The beginner’s trouble guide
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Shoots are thin |
Plants may be crowded or hungry. Thin them and check the soil moisture. |
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Leaves have tiny holes |
Flea beetles may be feeding. Cover young plants with fine mesh. |
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Flower buds open very fast |
Hot, dry weather speeds flowering. Keep plants moist and harvest sooner. |
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Leaves turn yellow |
Check for waterlogging, crowding or damaged roots. |
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Stems feel tough |
Harvest earlier, before buds open fully and the stalks age. |
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DON’T PANIC A few holes in the leaves are common on brassicas. Remove badly damaged leaves and keep mesh in place for new growth. |
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A COMMON MISTAKE Treating every flower as a failure. Choy sum is grown for its flowering stems; pick the buds while they are still closed. |
CHAPTER 9
Can I Pick It Yet?
Yes—pick Hon Tsai Tai when the shoots are tender and the flower buds are plump but still closed.
What “ready” looks like
Choy sum is ready when its flowering shoots are about 15–20 cm long and the buds are well formed but unopened. The stems should still bend easily and the leaves should look fresh. Cut the tender shoot with a clean knife just above a pair of leaves. If the plant branches, smaller side shoots may follow.
Harvest from late spring into autumn
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Shoots |
Cut at about 15–20 cm, while tender. |
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Buds |
Pick when plump and still closed. |
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How to cut |
Use a clean knife just above a pair of leaves. |
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More harvest |
Small side shoots may follow after the main cut. |
How often should I check?
Check the bed every few days as the buds begin to form; warm weather can open them quickly. Cut shoots while the buds are still closed for the mildest flavour and tenderest stems. If a few flowers open, the leaves, stems and flowers can still be eaten, though the stems may become tougher. Small, repeat sowings keep fresh shoots coming.
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READY TO HARVEST? Pick Hon Tsai Tai when the shoots are tender and the flower buds are plump but still closed. Cut with a clean knife above a pair of leaves. |
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TRY THIS Cook the stems first, then add the leaves and buds. A minute or two in a hot pan keeps their fresh texture. |
CHAPTER 10
From the Garden to the Kitchen
Hon Tsai Tai has mild mustard notes and tender stems that cook quickly.
The first rule: cook the stems briefly
Rinse the shoots well and trim any coarse ends. Slice thicker stems and leaves into bite-sized pieces. Stir-fry the stems with garlic for a minute, then add the leaves and buds and cook just until tender. Choy sum is also good steamed, in noodle dishes or added to soup. The small yellow flowers are edible, too.
Match choy sum to the dish
· Stir-fried: cook stems first, then add leaves and buds.
· Steamed: cook whole young shoots until just tender.
· In soup: add chopped stems and leaves near the end.
· Salad: use the tender young leaves and unopened buds.
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FROM THE KITCHEN Quick garlic choy sum: stir-fry chopped stems with garlic, then toss in the leaves and unopened buds until just tender. |
Storing fresh choy sum
Choy sum is best eaten soon after picking. Keep it unwashed in a loose bag in the refrigerator and use within a few days. If the stems lose their crispness, trim their ends and stand them briefly in cold water before cooking. Wash just before use.
When you have more than you can use
Choy sum tastes best fresh, so sow small batches rather than a large bed all at once. If you have extra shoots, blanch them briefly, cool quickly and freeze in meal-sized portions for soups or cooked dishes. The texture softens after thawing, so fresh stir-fries are best made with newly picked stems.
CHAPTER 11
Next Season Starts Now
Notes about sowing windows, moisture and harvest timing will help you enjoy a longer choy sum season next year.
Keep a tiny garden record
· Seed source and the exact Hon Tsai Tai variety name
· Date seeds were sown and seedlings appeared
· When the soil was ready for spring sowing
· How well the bed stayed moist in summer
· When the flower buds were ready to pick
· Whether the spring or autumn sowing did best
· Which dishes you enjoyed most
Saving seed and planning another crop
Choy sum can be left to flower and set seed, but it may cross with nearby flowering Brassica rapa crops such as pak choi, turnips or Chinese cabbage. The seed may not grow true to Hon Tsai Tai. For dependable purple stems next year, buy fresh seed. If you save seed as an experiment, leave healthy plants to form dry pods and label the seed clearly.
1. Choose a healthy plant with the purple shoots you liked.
2. Leave it in the garden and let it flower naturally.
3. Allow the seed pods to turn brown and dry on the plant.
4. Collect pods before they split and scatter seed.
5. Dry fully, label the variety and year, then store cool and dry.
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GOOD TO KNOW The small yellow flowers are edible. Once many buds open, the stems may become tougher, so harvest the shoots promptly. |
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WHAT I WOULD DO I would harvest a few shoots at a time and cook them the same day, while their stems are crisp. |
COME GROW WITH ME
CHOY SUM CHEAT SHEET
The page to come back to when you have soil on your hands and no time to reread the whole book.
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SOW |
February–April; late July–August |
About 0.5–0.6 cm deep |
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POSITION |
Sun in cool weather |
Light shade in warm spells |
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SPACING |
Rows 25–30 cm apart |
Plants 10–20 cm apart |
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WATER |
Keep soil evenly moist |
Avoid waterlogging |
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HARVEST |
About 30–50 days |
Pick with buds still closed |
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Sow |
Make small spring and late-summer sowings. |
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Thin |
Leave room for leafy flowering shoots. |
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Water |
Keep soil moist through warm, dry spells. |
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Protect |
Use fine mesh against flea beetles and caterpillars. |
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Harvest |
Cut tender stems while buds are closed. |
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Next season |
Rotate away from other brassicas. |
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HUNGARY IN ONE LINE Sow choy sum in spring or late summer, keep it evenly moist and pick tender purple shoots before the flower buds open. |
COME GROW WITH ME • CHOY SUM
Seasonal guidance is adapted for Hungarian home gardens.
