When to plant tomato in Edmonton

In Edmonton, typical last spring frost is May 9 and typical first fall frost is October 4. Typical last spring frost: May 9. Tomato in Edmonton is not realistic outdoors: 48 suitable days are fewer than the 55 days this plant usually needs.

Tomato

How to grow Tomato Edmonton climate Weekly temperatures and windows

Where are you growing?

Not realistic outdoors

Not realistic in greenhouse

Tomato in Edmonton is doable with planning under fleece. 86 suitable days are enough for fast varieties (55 days) but not slow ones (90 days).

Start indoors: April 1 – May 8
Transplant outside: May 31 – July 7
Harvest: July 25 – September 28
Season vs crop: 86 grow days vs 55–90 needed
Typical frost (last spring – first fall): May 1 – October 11

Tomato in Edmonton is doable with planning under fleece. 86 suitable days are enough for fast varieties (55 days) but not slow ones (90 days).

Start seeds indoors April 1 – May 8, then transplant May 31 – July 7 so the crop can finish under fleece.

Estimate. Protection varies with the cover, the weather and how you vent it.

Fleece adds about 1–4 °C on frosty nights, depending on its weight. Remove it on warm days.

Fleece also cuts light: about 5–10 % for light fleece, up to 50–70 % for heavy grades. Take it off by day once frosts are over.

Cover dates are modelled from weather-model data using published greenhouse studies. They are not measured in your greenhouse. A max–min thermometer inside will tell you more.

Typical last frost estimate range May 4 – April 19, depending on the cover and the night.

Planting conditions

Start indoors
Grow indoors
Harden off
Transplant outside
Grow outdoors
Harvest

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 row86

Days to harvest55–90 days from transplant

Apr 1 – May 8

Start indoors

May 9 – May 23

Grow indoors

May 24 – May 30

Harden off

May 31

Transplant outside

Jun 1 – Jul 24

Grow outdoors

Jul 25 – Sep 28

Harvest

Activity	Window	Notes
Start indoors	Apr 1 – May 8	Sow indoors before the outdoor window.
Grow indoors	May 9 – May 23	Seedlings grow indoors until harden or transplant.
Harden off	May 24 – May 30	Acclimate seedlings outdoors before planting.
Transplant outside	May 31	Move plants outside on this day (start of the plant-out window).
Grow outdoors	Jun 1 – Jul 24	Plants grow outdoors until harvest.
Harvest	Jul 25 – Sep 28	Expected harvest from typical days to harvest.

Start indoors
Grow indoors
Harden off
Transplant outside
Grow outdoors
Harvest

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). Adjust a week or two for your conditions.

Protected frost and sowing dates are modelled estimates from weather-model data and published greenhouse studies, not measured in your greenhouse. A max–min thermometer inside will tell you more.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 29 °C70 – 84 °F21 – 29 °C (70 – 84 °F)) and tolerable (13 – 35 °C55 – 95 °F13 – 35 °C (55 – 95 °F)) ranges, from modelled cover temperatures for the growing method you selected.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostMay 1

Low-risk last spring frostMay 12

Typical first fall frostOctober 11

Low-risk first fall frostSeptember 28

Frost-free days162

Earliest indoor seed startApril 1

Latest indoor seed startMay 8

Transplant outdoorsMay 31 – July 7

Direct sow windownot recommended here

Suitable growing windowMay 31 – August 24 (86 days)

Expected harvestJuly 25 – September 28

How these dates are judged

Ideal conditions: Daytime air from 21 – 29 °C70 – 84 °F21 – 29 °C (70 – 84 °F).
Suitable conditions: Daytime air from 13 – 35 °C55 – 95 °F13 – 35 °C (55 – 95 °F).
Last frost and first frost: Typical spring and fall frost dates for Edmonton, shown in the key dates.
Days to harvest: 55–90 days from transplant, 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. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for Edmonton

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for Edmonton use ERA5-Land cell 53.55, -113.47. How we calculated this · Algorithm 2026-10-season-10.

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