Red cabbage · Edmonton, Alberta, Canada
When to plant red cabbages in Edmonton
Main outdoor window
22 Apr - 13 May
The window this page is built around.
Timed from last spring frost
13 May
In Edmonton, on your chosen risk.
Ready to pick
1 Sep - 30 Nov
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 Edmonton
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
18 Mar - 8 Apr
Eight weeks before your last frost, under cover or on a windowsill.
Transplant
22 Apr - 13 May
Three weeks before your last frost.
Harvest
1 Sep - 30 Nov
Red cabbages through the year
Against the frost risk in Edmonton
Why these dates
Start indoors about eight weeks before the last frost and plant out three weeks before it. The colour deepens in cool weather, so an autumn crop is better than a summer one.
Hardy to roughly -8C. Heads left standing take frost without splitting, which is the usual reason to leave them out rather than lift them early.
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. Red cabbages are timed from 8 weeks before that frost for an indoor start, with planting out 3 weeks before it, and this page simply resolves those offsets against the frost date computed for Edmonton.
The median frost-free season here is 137 days, against 90 to 120 days to maturity for this crop counted from planting out. That margin is what decides whether a late sowing is worth attempting.
Also in Edmonton
Other vegetables to time
Growing red cabbages in Edmonton
When should I plant red cabbages in Edmonton?
Aim for 22 Apr - 13 May in an average year. If you would rather not gamble on the weather, wait until 1-22 May - by then frost has finished in nine years out of ten.
When will red cabbages be ready to harvest in Edmonton?
Expect to start picking around 1 Sep - 30 Nov, based on 90 to 120 days to maturity from the planting date calculated for this location.
How much frost will red cabbages tolerate?
Hardy to roughly -8C. Heads left standing take frost without splitting, which is the usual reason to leave them out rather than lift them early.