🥬 Napa cabbage
The backbone of the northern Chinese autumn garden: sown around early August, cut before the first hard frost.
Napa cabbage at a glance
Is Napa cabbage frost tolerant?
Yes, through light frosts. Damage starts at -5°C and it is killed below -10°C.
What temperature does Napa cabbage grow best in?
It grows best between 8 and 22°C. Below 5°C it stops growing altogether, and above 26°C it slows down.
How many days does Napa cabbage take to mature?
About 60–80 days. That is a typical figure: it needs roughly 780 °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 Napa cabbage a cool-season or warm-season crop?
A cool-season crop. It does best in the mild weather of spring and autumn (and through winter where winters are mild), and slows down in summer heat above 26°C.
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, 28) − 5), and Napa cabbage is ready when that total reaches 780. 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 | 780 °C·dThe heat budget it must accumulate before it is ready to pick. |
| Comfortable range | 8–22°CWhere it grows without stress. |
| Frost damage below | -5°CLeaves start taking frost damage below this low. |
| Killed below | -10°CBelow this it does not come back. |
| Heat stress above | 26°CAbove this the plant slows down and stops setting fruit well. |
| Typical time to harvest | 60–80 days |
| Yield per bed | 3 heads |
Things worth knowing
- Napa cabbage only hearts up in cool weather — sown too warm it makes leaves and never a head.
- It is over 90% water, which is why it stores so well and yet cannot survive freezing through.
Where and when to sow Napa cabbage
Pick your city to see the months when Napa cabbage scores well against that city's real climate records: