What hardiness zone is Ottawa?

Ottawa is in Canadian Hardiness Zone 5. Moderate – many shrubs, roses, most vegetables

When is the last frost in Ottawa?

The average last frost date in Ottawa is Late April (Apr 20–30). Always watch local forecasts as it varies year to year.

What vegetables grow best in Ottawa?

Zone 5 gardens in Ottawa do well with cold-hardy brassicas, root vegetables, and many perennials. With a short frost-free period of around 155 days, choose varieties with days-to-maturity suited to your zone.

Gardening in Ottawa, Ontario | GardeningKnowHow.ca

Gardening in Ontario

Ontario's diverse geography spans Zone 3 in the north to Zone 7 in the Niagara Peninsula. Southern Ontario's Great Lakes moderate temperatures, extending seasons and enabling wine grapes, tender perennials, and a remarkable breadth of food crops.

Gardening in Calgary

Video

Woman tending a flower garden in Calgary — Tending the flower beds

Woman picking flowers with the Calgary skyline behind her — Picking flowers, city skyline

Woman harvesting vegetables in a Calgary rooftop garden — Rooftop harvest

Planting Calendar – September 2026

Ottawa

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Oct

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Dec

Growing season Shoulder This month

Task	Details
Start Indoors	Garlic planting begins (plant before freeze)
Direct Sow	Winter crops in cold frame (Zone 5+)
Key Tasks	Collect & dry seeds; compost healthy tops

Frost Dates – Ottawa

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Last Spring Frost

Late April (Apr 20–30)

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First Fall Frost

Mid October (Oct 10–20)

Frost-free period: Approximately 155 days. Always check Environment Canada's local forecast — frost dates can vary by 2–3 weeks depending on microclimates, elevation, and annual weather patterns.