Oregano · Hiroshima, Hiroshima, Japan
When to plant oregano in Hiroshima
Main outdoor window
6-27 Apr
The window this page is built around.
Timed from last spring frost
6 April
In Hiroshima, on your chosen risk.
Ready to pick
25 Jun - 15 Jul
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 Hiroshima
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.
Start indoors
9 Feb - 2 Mar
Eight weeks before your last frost, under cover or on a windowsill.
Plant
6-27 Apr
Around your last frost.
Harvest
25 Jun - 15 Jul
Oregano through the year
Against the frost risk in Hiroshima
Why these dates
Slow from seed. Start indoors eight weeks before last frost, or take cuttings from an established plant.
Hardy to -18C in well-drained soil. Winter wet, not winter cold, is what kills oregano.
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. Oregano are timed from 8 weeks before that frost for an indoor start, with planting out 0 weeks after it, and this page simply resolves those offsets against the frost date computed for Hiroshima.
Growing oregano in Hiroshima
When should I plant oregano in Hiroshima?
Aim for 6-27 Apr in an average year. If you would rather not gamble on the weather, wait until 17 Apr - 8 May - by then frost has finished in nine years out of ten.
When will oregano be ready to harvest in Hiroshima?
Expect to start picking around 25 Jun - 15 Jul, based on 80 to 100 days to maturity from the planting date calculated for this location.
How much frost will oregano tolerate?
Hardy to -18C in well-drained soil. Winter wet, not winter cold, is what kills oregano.