When to plant sweet potato in Ottawa

In Ottawa, typical last spring frost is April 28 and typical first fall frost is October 29. Typical last spring frost: April 28. Sweet potato in Ottawa is not realistic outdoors: 83 suitable days are fewer than the 85 days this plant usually needs.

Sweet potato

How to grow Sweet potato Ottawa climate Weekly temperatures and windows

Where are you growing?

Not realistic outdoors

Not realistic in greenhouse

Tight fit in a cold frame

Sweet potato in Ottawa is doable with planning under fleece. 112 suitable days are enough for fast varieties (85 days) but not slow ones (140 days).

When to plantMay 16 – June 14

Harvest: August 9 – October 26
Season vs crop: 112 grow days vs 85–140 needed
Typical frost (last spring – first fall): April 15 – November 9

Sweet potato in Ottawa is doable with planning under fleece. 112 suitable days are enough for fast varieties (85 days) but not slow ones (140 days).

Start slips April 4 – May 3, then transplant May 16 – June 14 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 April 23 – April 7, depending on the cover and the night.

Planting conditions

Suitable growing days in a row112

Days to harvest85–140 days from planting

No planting window is recorded for this place.

Too cold
Frost line

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 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F)) and tolerable (16 – 35 °C61 – 95 °F16 – 35 °C (61 – 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 frostApril 15

Low-risk last spring frostApril 26

Typical first fall frostNovember 9

Low-risk first fall frostOctober 26

Frost-free days207

Earliest indoor seed startApril 4

Latest indoor seed startMay 3

Transplant outdoorsMay 16 – June 14

Direct sow windownot recommended here

Suitable growing windowMay 16 – September 4 (112 days)

Expected harvestAugust 9 – October 26

How these dates are judged

Ideal conditions: Daytime air from 21 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F).
Suitable conditions: Daytime air from 16 – 35 °C61 – 95 °F16 – 35 °C (61 – 95 °F).
Last frost and first frost: Typical spring and fall frost dates for Ottawa, shown in the key dates.
Days to harvest: 85–140 days from planting, 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 Ottawa

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 Ottawa use ERA5-Land cell 45.41, -75.70. How we calculated this · Algorithm 2026-10-season-10.

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