🥬 Kale
An ultra-hardy leafy green that tastes better after frost.
Kale at a glance
Is Kale frost tolerant?
Yes — it is one of the hardier crops. It shrugs off frost down to -8°C and is only killed below -15°C.
What temperature does Kale grow best in?
It grows best between 6 and 24°C. Below 4°C it stops growing altogether, and above 27°C it slows down.
How many days does Kale take to mature?
About 50–65 days. That is a typical figure: it needs roughly 600 °C·d of warmth above 4°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 Kale 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 27°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) − 4), and Kale is ready when that total reaches 600. That is why the same seed takes a very different number of days in Dublin and in Guangzhou.
| Base temperature | 4°CBelow this, the plant accumulates no growing degree days at all. |
|---|---|
| Degree days to maturity | 600 °C·dThe heat budget it must accumulate before it is ready to pick. |
| Comfortable range | 6–24°CWhere it grows without stress. |
| Frost damage below | -8°CLeaves start taking frost damage below this low. |
| Killed below | -15°CBelow this it does not come back. |
| Heat stress above | 27°CAbove this the plant slows down and stops setting fruit well. |
| Typical time to harvest | 50–65 days |
| Yield per bed | 8 bunches |
Things worth knowing
- Kale, broccoli, cabbage and cauliflower are all one species — wild cabbage bred into different organs.
- Frost makes kale convert starch to sugar as antifreeze — winter kale is noticeably sweeter.
Where and when to sow Kale
Pick your city to see the months when Kale scores well against that city's real climate records: