Kai-lan · Tokyo, Tokyo, Japan
When to plant kai-lan in Tokyo
Main outdoor window
22 Mar - 5 Apr
The window this page is built around.
Timed from last spring frost
8 March
In Tokyo, on your chosen risk.
Ready to pick
1 Jul - 31 Oct
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Tokyo
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Sow direct
22 Mar - 5 Apr
Two weeks after your last frost.
Harvest
1 Jul - 31 Oct
Kai-lan through the year
Against the frost risk in Tokyo
Why these dates
Sow from two weeks after the last frost and again every three weeks. Cutting the main stem above a leaf brings a second flush of side shoots.
Takes a light frost around -4C. Cold makes the stems sweeter but slows them to a stop, so late sowings need a cloche to finish.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Kai-lan are timed for direct sowing 2 weeks after it, and this page simply resolves those offsets against the frost date computed for Tokyo.
The median frost-free season here is 291 days, against 50 to 70 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Tokyo
Other vegetables to time
Growing kai-lan in Tokyo
When should I plant kai-lan in Tokyo?
Aim for 22 Mar - 5 Apr in an average year. If you would rather not gamble on the weather, wait until 10-24 Apr - by then frost has finished in nine years out of ten.
When will kai-lan be ready to harvest in Tokyo?
Expect to start picking around 1 Jul - 31 Oct, based on 50 to 70 days to maturity from the planting date calculated for this location.
How much frost will kai-lan tolerate?
Takes a light frost around -4C. Cold makes the stems sweeter but slows them to a stop, so late sowings need a cloche to finish.