Cowpea · Ōta, Tokyo, Japan
When to plant cowpeas in Ōta
Main outdoor window
22 Mar - 12 Apr
The window this page is built around.
Timed from last spring frost
8 March
In Ōta, on your chosen risk.
Ready to pick
31 May - 30 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 Ōta
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 - 12 Apr
Two weeks after your last frost.
Harvest
31 May - 30 Jun
Cowpeas through the year
Against the frost risk in Ōta
Why these dates
Sow two weeks after the last frost once soil is genuinely warm. Cowpeas grow fast enough in heat to be sown as a second crop after an early harvest.
Tender at 0C, with no useful frost tolerance at either end.
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. Cowpeas are timed for direct sowing 2 weeks after it, and this page simply resolves those offsets against the frost date computed for Ōta.
The median frost-free season here is 291 days, against 70 to 100 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Ōta
Other grains to time
Growing cowpeas in Ōta
When should I plant cowpeas in Ōta?
Aim for 22 Mar - 12 Apr in an average year. If you would rather not gamble on the weather, wait until 10 Apr - 1 May - by then frost has finished in nine years out of ten.
When will cowpeas be ready to harvest in Ōta?
Expect to start picking around 31 May - 30 Jun, based on 70 to 100 days to maturity from the planting date calculated for this location.
How much frost will cowpeas tolerate?
Tender at 0C, with no useful frost tolerance at either end.