Zone 13 is the hottest USDA zone and the only one that is frost-free year-round, with average winter lows above 60°F. There is no last spring frost and no first autumn frost to plan around, so in Zone 13 you plant by heat and by the wet and dry seasons, not by frost. The limits on what grows are heat, humidity, rain and pests rather than cold. All numbers below are published ranges, not promises for your garden: check your local extension service before you plant.
Bok choy, also called pak choi, is a fast Asian green with crisp white stems and tender dark leaves, ready in about six to eight weeks. In Zone 13 it is a cool-season crop that benefits from a little shade — it is one of the few vegetables in this series that prefers part shade, which is an advantage under a fierce tropical sun. Sow it in the coolest months, keep it watered, and harvest before heat makes it bolt.
Zone 13 timing for bok choy
The table below is the whole plan in one place.
| Step | Zone 13 timing |
|---|---|
| Average winter low | Above 60°F |
| Last spring frost | None — frost-free year-round |
| First autumn frost | None — frost-free year-round |
| Best planting window | Coolest months only, roughly November to February |
| Start indoors | Optional head start indoors a few weeks before transplanting |
| Direct sow outdoors | Sow direct the coolest months, roughly November to February, or transplant seedlings |
| Days to germination | 7–10 days |
| Days to maturity | 45–60 days |
| Cold tolerance | hardy |
When to sow bok choy in Zone 13
Sow bok choy in the coolest months, roughly November to February, in batches every two to three weeks. Its short season means even a late cool-season sowing can finish, but heat is the enemy: bok choy bolts quickly once days get hot, so sow early in the cool season and do not push your luck into warming weather. Use the seed-starting calculator to work backwards from your transplant date.
Starting bok choy: indoors or direct sowing
Bok choy can be started indoors or direct-sown. Starting indoors gives a head start on the short cool season and protects seedlings from heavy rain; direct sowing is simpler and works well if the seed bed stays damp. Transplant carefully when seedlings have a few true leaves, handling them by a leaf rather than the stem.
Soil, spacing and sun
Bok Choy needs part shade. Space plants 8–12 inches apart — crowded plants compete for light, water and air, and disease spreads faster between touching leaves in humid tropical air. Bok choy wants rich, moisture-holding soil with plenty of compost, and it tolerates part shade better than most vegetables — a spot with morning sun and afternoon shade is ideal in Zone 13. Keep the soil evenly moist and the pH in the range in the table below. Use the plant spacing calculator to work out how many plants fit in your bed at that spacing.
Watering bok choy in Zone 13
Water needs are moderate, but bok choy is thirsty for a leafy green and wilts quickly in dry soil. Water at the base in the morning, mulch to hold moisture, and water more often in dry spells. Even watering keeps the stems crisp and sweet; drought makes them tough and bitter.
Companion plants
Good companions for bok choy include marigolds, basil, onions, lettuce. These are the companions listed for this crop in standard horticultural references: they share similar needs, and some, like marigolds, are traditionally planted to help confuse or deter pests. Plant companions in the same bed or nearby, not in a separate corner of the garden, so they actually share the space. Avoid planting heavy feeders that will compete for the same nutrients in the same spot.
Common pests and problems
The pests to watch for are cabbage worms, aphids, flea beetles and slugs. Cabbage worms hide in the folds of the leaves, so check the hearts of plants weekly. Slugs love the damp, shady conditions bok choy likes, so keep mulch back from stems and check after rain. Row cover over young plants prevents most of it.
Harvest and storage
Harvest bok choy whole once heads are a good size, about six to eight weeks after sowing, or pick outer leaves and let the centre keep growing. Cut at the base with a sharp knife, wash the stems well — grit hides between the leaves — and use the same day. Do not wait for giant heads in warming weather: a small, sweet head beats a bolted one.
Succession and rotation in Zone 13
Succession sowing works in Zone 13, but only inside the cool season: sow a small batch every two to three weeks while the weather stays mild, so the harvest stretches out instead of arriving all at once. Once heat builds, stop sowing — a late batch will bolt before it is worth picking. Rotate crops so bok choy does not follow another Brassicaceae family crop in the same bed next season. Keep notes on what you sowed and when: in a climate with no frost dates, your own records are the most useful planting guide you will have for the next cool season.
Related Zone 13 guides
More Zone 13 guides: Arugula in Zone 13 and the same crop in a cooler zone, Bok Choy in Zone 11. The December in Zone 13 guide shows what else to plant in that month, and the planting calendar hub brings all the Zone 13 guides together.
Frequently asked questions
When should I plant bok choy in Zone 13?
Sow bok choy in the coolest months, roughly November to February. Zone 13 is frost-free with winter lows above 60°F, so there is no last or first frost date to work from — plant by the cool season, not by frost. Check your local extension service for the best sowing weeks in your area.
Does bok choy really prefer shade in Zone 13?
Yes — part shade is listed for this crop, and in the tropics it is a real advantage. Morning sun plus afternoon shade keeps the soil cooler, slows bolting and keeps leaves tender. Full tropical sun all day is too much for bok choy, even in the cool season.
Why did my bok choy bolt before forming a head?
Bolting is triggered by heat and by transplant shock, and by sowing too late in the cool season. Sow early, keep plants evenly watered, transplant gently, and give them afternoon shade — and accept that in Zone 13 bok choy is a short-season crop, not a long one.
What soil and spacing do bok choy need?
It needs part shade, soil pH 6.0–7.5, and spacing of 8–12 inches between plants. Work compost into the bed before planting and test the soil rather than guessing the pH.