When to plant sweet corn in Edmonton

Where are you growing?

Tight fit

Tight fit in greenhouse

Comfortable in a cold frame

Sweet corn in Edmonton is doable with planning outdoors. 73 suitable days are enough for fast varieties (60 days) but not slow ones (90 days).

When to plantMay 30 – July 4

Harvest: 60–90 days from seed
Season vs crop: 73 grow days vs 60–90 needed
Typical frost (last spring – first fall): May 13 – October 14

Sweet corn in Edmonton is doable with planning outdoors. 73 suitable days are enough for fast varieties (60 days) but not slow ones (90 days).

Planting conditions

Direct sow

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row73

Days to harvest60–90 days from seed

May 30 – Jul 4

Direct sow

Activity	Window	Notes
Direct sow	May 30 – Jul 4	Plant outdoors in this window.

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost. Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 32 °C) and tolerable (13 – 35 °C) ranges.

Planting uses sow / plant-out rules (frost, soil germination, night, and last-sow): green when plantable, blue diagonal when nights or soil are too cold, amber cross-hatch when too hot, faint for other calendar limits. Growing shows daytime air against this plant’s ideal and tolerable ranges across the year.

Key dates

Typical last spring frostMay 13

Safer last spring frostMay 13

Typical first fall frostOctober 14

Safer first fall frostOctober 14

Frost-free days153

Outdoor sow dateMay 30

Direct sow windowMay 30 – July 4

Suitable growing windowMay 30 – August 10 (73 days)

How these dates are judged

Ideal conditions: Daytime air from 21 – 32 °C.
Suitable conditions: Daytime air from 13 – 35 °C.
Last frost and first frost: Typical spring and fall frost dates for Edmonton, shown in the key dates.
Days to harvest: 60–90 days from seed, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. The year strip and weekly chart use the same window: air ratings only colour weeks inside it.

Growing window for Sweet corn: May 30 – Aug 10 (73 days)

Planting window for Sweet corn: May 30 – Jul 4 (36 days)

Usually too cold: Aug 17 – Dec 31

Outdoors: weekly temperatures and windows

Temperatures across the year for Edmonton. Shaded bands are this plant’s ideal and tolerable daytime air ranges. Growing is daytime air suitability; Planting is sow / plant-out conditions (same colour language). Window brackets mark each stretch.

Ideal range
Tolerable range
Possible min to max
Average min to max
Suitable
Tolerable
Too cold
Too hot

Selected week · tap a week or use the arrows

Week 22 · May 25 – May 31

Average 9 to 20 °C · Possible 3 to 30 °C

Growing: too cold

Planting: too cold

A week is in range when its average low and high sit inside the tolerance band 13 to 35 °C; it is suitable when that average range also overlaps the ideal 21 to 32 °C band and possible readings stay within 0 °C to 35 °C. Crossing a possible limit, or missing the ideal band, makes it tolerable; any chance of frost (possible low below 0 °C) makes it too cold. When a sowing window is calculated, weeks outside that window are uncoloured even if air is in range.

Based on average frost dates.

Show all 53 weeks

Cover method weekly charts

Outdoor weekly chart is above. Open a cover chart only if you grow under fleece, a cold frame, or an unheated greenhouse.

Other plants for Edmonton

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

How we calculated this

Data: ERA5-Land via Open-Meteo, cell 53.55, -113.47, years 2019–2026 (not a 30-year climate normal yet).
Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
Crop rule: Local windows for Sweet corn from frost dates, temperature ratings, and crop timing rules.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-6).

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