Radish · Edmonton, Alberta, Canada
When to plant radishes in Edmonton
Main outdoor window
15-22 Apr
The window this page is built around.
Timed from last spring frost
13 May
In Edmonton, on your chosen risk.
Ready to pick
7-15 May
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.
Sow for autumn
23 Jul - 13 Aug
Counting back 44 days from your first frost so the crop matures in time.
Sow direct
15-22 Apr
Four weeks before your last frost.
Harvest
7-15 May
Radishes through the year
Against the frost risk in Edmonton
Why these dates
Sow every week in spring and autumn. Summer sowings turn woody and hot - stop when daytime temperatures pass 25C and resume in late summer.
Handles -6C easily and is often the first and last thing harvested in the year.
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. Radishes are timed for direct sowing 4 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 22 to 30 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Edmonton
Other vegetables to time
Growing radishes in Edmonton
When should I plant radishes in Edmonton?
Aim for 15-22 Apr in an average year. If you would rather not gamble on the weather, wait until 24 Apr - 1 May - by then frost has finished in nine years out of ten.
When will radishes be ready to harvest in Edmonton?
Expect to start picking around 7-15 May, based on 22 to 30 days to maturity from the planting date calculated for this location.
How much frost will radishes tolerate?
Handles -6C easily and is often the first and last thing harvested in the year.