Vegetable · Brassicaceae
When to plant kohlrabi
A swollen stem rather than a root, sitting on the soil surface, and ready in under two months. Picked small - anything over 8 cm turns woody.
Start seed indoors
5 weeks before
Counted from your last spring frost.
Plant out
2 weeks after
Counted from your last spring frost.
Sow direct
2 weeks before
Counted from your last spring frost.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Seed packets rarely give calendar dates, because a date that suits one latitude is wrong at another. They give offsets from the last spring frost instead, and those offsets are what make kohlrabi plantable anywhere.
- Start seed indoors 5 weeks before the last frost.
- Plant out 2 weeks after the last frost.
- Sow direct 2 weeks before the last frost.
- Expect 55–75 days to maturity, counted from sowing.
- Sow again every 21 days for a continuous supply.
- Can also be sown in late summer for an autumn crop.
Getting the timing right
Sow direct two weeks before the last frost and every three weeks after, avoiding high summer. A late-summer sowing crops into autumn.
Frost tolerance
Tolerates about -6C. The exposed stem is more vulnerable than a buried root would be, so a hard frost damages it directly.
Classified as hardy, with damage expected below -6°C (21.2°F)21.2°F (-6°C).