🥒 Bitter melon
A tropical climber that wants heat, humidity and a frame. The first frost ends it outright.
Bitter melon at a glance
Is Bitter melon frost tolerant?
No. Cold hurts it even above freezing: damage starts at 4°C and it is killed below 1°C. Sow or plant it out only after your last frost.
What temperature does Bitter melon grow best in?
It grows best between 18 and 32°C. Below 12°C it stops growing altogether, and above 36°C it slows down.
How many days does Bitter melon take to mature?
About 70–90 days. That is a typical figure: it needs roughly 1120 °C·d of warmth above 12°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 Bitter melon a cool-season or warm-season crop?
A warm-season crop. It needs warm days and nights, so it goes in after the last frost, once temperatures are reliably above 18°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, 35) − 12), and Bitter melon is ready when that total reaches 1120. That is why the same seed takes a very different number of days in Dublin and in Guangzhou.
| Base temperature | 12°CBelow this, the plant accumulates no growing degree days at all. |
|---|---|
| Degree days to maturity | 1120 °C·dThe heat budget it must accumulate before it is ready to pick. |
| Comfortable range | 18–32°CWhere it grows without stress. |
| Frost damage below | 4°CLeaves start taking frost damage below this low. |
| Killed below | 1°CBelow this it does not come back. |
| Heat stress above | 36°CAbove this the plant slows down and stops setting fruit well. |
| Typical time to harvest | 70–90 days |
| Yield per bed | 10 fruits |
Things worth knowing
- The bitterness comes from cucurbitacins — greener means more bitter, and a ripe yellow one turns sweetish with red pulp.
- Below about 15°C it stops growing almost completely, making it one of the fussiest gourds about temperature.
Where and when to sow Bitter melon
Pick your city to see the months when Bitter melon scores well against that city's real climate records: