Buckwheat · Tokyo, Tokyo, Japan
When to plant buckwheat in Tokyo
Main outdoor window
15-29 Mar
The window this page is built around.
Timed from last spring frost
8 March
In Tokyo, on your chosen risk.
Ready to pick
24 May - 13 Jun
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
15-29 Mar
One week after your last frost.
Harvest
24 May - 13 Jun
Buckwheat through the year
Against the frost risk in Tokyo
Why these dates
Sow after the last frost, any time up to about eleven weeks before the first. Because it matures so fast it can follow an early crop and still finish, and it smothers weeds while doing so.
Killed outright by the lightest frost, which is exactly why it works as a summer cover crop that clears itself away in autumn.
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. Buckwheat are timed for direct sowing 1 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 70 to 90 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 grains to time
Growing buckwheat in Tokyo
When should I plant buckwheat in Tokyo?
Aim for 15-29 Mar in an average year. If you would rather not gamble on the weather, wait until 3-17 Apr - by then frost has finished in nine years out of ten.
When will buckwheat be ready to harvest in Tokyo?
Expect to start picking around 24 May - 13 Jun, based on 70 to 90 days to maturity from the planting date calculated for this location.
How much frost will buckwheat tolerate?
Killed outright by the lightest frost, which is exactly why it works as a summer cover crop that clears itself away in autumn.