Safe to Plant

Canterbury bells · Chũ, Bac Ninh, Vietnam

When to sow canterbury bells in Chũ

Main outdoor window

19 Feb - 19 Mar

The window this page is built around.

Timed from last spring frost

8 January

In Chũ, on your chosen risk.

Ready to pick

1 Jun - 31 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 Chũ

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

19 Feb - 19 Mar

Six weeks after your last frost.

Move to final position

28 May - 25 Jun

20 weeks after your last frost.

In flower

1 Jun - 31 Jul

Frost tolerance
Hardy
Damaged below
-18°C (-0.4°F)
Days to flowering
335–385
Hardy to
Zone 4a–8a
Min soil temp
15°C (59°F)
Spacing
35 cm
Sowing depth
1 mm (0 in)
Sun
Partial

Canterbury bells through the year

Against the frost risk in Chũ

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Frost risk Sow direct Plant out Harvest Today

Why these dates

Sow on the surface in early summer, six weeks after the last frost, and move the rosettes to their final position in autumn. Flowers the following June for about five weeks. Deadheading the main spike brings a lighter second flush from the side shoots.

Hardy to about -18C as a rosette, though it dislikes a wet winter and is safer on free-draining ground or with a mulch of grit around the crown.

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. Canterbury bells are timed with planting out 20 weeks after it, and this page simply resolves those offsets against the frost date computed for Chũ.

Chũ sits in zone 10a, which is milder than this crop wants, and a winter that never really arrives is its own problem. The dates below still describe the right time of year; the open question is survival rather than timing.

This is a two-season crop, so the dates above describe a sowing in one year and a flowering in the next. The plant spends the winter in the ground as a small rosette, which is why the frost-free season in Chũ does not limit it the way it would limit a tomato: it is not trying to finish before the cold arrives, it is trying to be well enough rooted to sit through it. Sowing too late is the real risk, because a plant that goes into winter undersized often fails to flower at all the following year.

See every crop timed for Chũ →

Growing canterbury bells in Chũ

When should I plant canterbury bells in Chũ?

Aim for 19 Feb - 19 Mar in an average year. If you would rather not gamble on the weather, wait until 5 Mar - 2 Apr - by then frost has finished in nine years out of ten.

When will canterbury bells be ready to harvest in Chũ?

Expect to start picking around 1 Jun - 31 Jul, based on 335 to 385 days to maturity from the planting date calculated for this location.

How much frost will canterbury bells tolerate?

Hardy to about -18C as a rosette, though it dislikes a wet winter and is safer on free-draining ground or with a mulch of grit around the crown.