Celeriac · Okazaki, Aichi, Japan
When to plant celeriac in Okazaki
Main outdoor window
25 Mar - 15 Apr
The window this page is built around.
Timed from last spring frost
11 March
In Okazaki, on your chosen risk.
Ready to pick
13 Jul - 12 Aug
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 Okazaki
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
31 Dec - 21 Jan
Ten weeks before your last frost, under cover or on a windowsill.
Plant out
25 Mar - 15 Apr
Two weeks after your last frost.
Harvest
13 Jul - 12 Aug
Celeriac through the year
Against the frost risk in Okazaki
Why these dates
Start indoors 10 weeks before the last frost and plant out after it, keeping the crown at soil level rather than buried. Remove the lower leaves in late summer so the root swells cleanly.
Stands to about -8C in the ground and improves with a touch of frost, so it can be left and lifted as needed well into winter.
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. Celeriac are timed from 10 weeks before that frost for an indoor start, with planting out 2 weeks after it, and this page simply resolves those offsets against the frost date computed for Okazaki.
The median frost-free season here is 286 days, against 110 to 140 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Okazaki
Other vegetables to time
Growing celeriac in Okazaki
When should I plant celeriac in Okazaki?
Aim for 25 Mar - 15 Apr in an average year. If you would rather not gamble on the weather, wait until 6-27 Apr - by then frost has finished in nine years out of ten.
When will celeriac be ready to harvest in Okazaki?
Expect to start picking around 13 Jul - 12 Aug, based on 110 to 140 days to maturity from the planting date calculated for this location.
How much frost will celeriac tolerate?
Stands to about -8C in the ground and improves with a touch of frost, so it can be left and lifted as needed well into winter.