🥬 Bok Choy
Adaptable and quick — a leafy green for every season.
Bok Choy at a glance
Is Bok Choy frost tolerant?
Barely. A light frost is enough to damage it (-1°C), and it is killed below -5°C. Treat it as frost-tender.
What temperature does Bok Choy grow best in?
It grows best between 10 and 26°C. Below 5°C it stops growing altogether, and above 30°C it slows down.
How many days does Bok Choy take to mature?
About 35–50 days. That is a typical figure: it needs roughly 450 °C·d of warmth above 5°C, so a warm season gets it there sooner and a cool one later. The city calendars below give the sow and harvest dates for each place.
Is Bok Choy a cool-season or warm-season crop?
Somewhere in between: it cannot take frost, so plant it after your last frost, but it starts growing from about 5°C — earlier in spring than the true heat-lovers.
What the numbers mean
These are the actual parameters this game runs on. Growth is driven by growing degree days: each day contributes max(0, min(mean temp, 32) − 5), and Bok Choy is ready when that total reaches 450. That is why the same seed takes a very different number of days in Dublin and in Guangzhou.
| Base temperature | 5°CBelow this, the plant accumulates no growing degree days at all. |
|---|---|
| Degree days to maturity | 450 °C·dThe heat budget it must accumulate before it is ready to pick. |
| Comfortable range | 10–26°CWhere it grows without stress. |
| Frost damage below | -1°CLeaves start taking frost damage below this low. |
| Killed below | -5°CBelow this it does not come back. |
| Heat stress above | 30°CAbove this the plant slows down and stops setting fruit well. |
| Typical time to harvest | 35–50 days |
| Yield per bed | 8 heads |
Things worth knowing
- Bok choy, napa cabbage and rapeseed are close cousins — one species, many shapes.
- Big day–night temperature swings make the leaves thicker and sweeter.
Where and when to sow Bok Choy
Pick your city to see the months when Bok Choy scores well against that city's real climate records: