Ottawa Planting Calendar 2026 — Zone 5a Vegetable Guide

Ottawa sits in Zone 5a — not as long a season as Toronto but considerably more productive than Edmonton or Calgary. With a last frost around May 6–10 and first frost around October 5, Ottawa gardeners have roughly 150 frost-free days to work with. That's enough time for a full range of vegetables, including heat-loving crops like tomatoes, peppers, and cucumbers.

Ottawa's Growing Zone

Ottawa falls in USDA/Canadian Hardiness Zone 5a, with the Gatineau side (Quebec) often in Zone 5b. The Ottawa River valley creates mild microclimates — downtown and riverside gardens often experience earlier springs and later falls compared to suburban or rural Ottawa.

Key dates for planning:

• Average last spring frost: May 6–10
• Average first fall frost: October 5
• Frost-free growing days: approximately 148–155

Indoor Seed Starting Schedule

January/February

• Onions and leeks — Start 10–12 weeks before transplant date (mid-January to mid-February for May 1–5 transplants)
• Peppers — Start 10–12 weeks before last frost (late January to early February)

February/March

• Tomatoes — Start 6–8 weeks before transplant; begin mid-February to early March for late April/early May transplants
• Celery — Start 10–12 weeks before transplant; mid-February
• Broccoli, cabbage, cauliflower — Start 4–6 weeks before transplant; start mid-March for late April transplants

March/April

• Cucumbers — Start 3–4 weeks before last frost; mid-April
• Zucchini and squash — Start 2–3 weeks before last frost; late April
• Basil — Start 4–6 weeks before last frost; mid-April

Use the planting date calculator at MyGardenPlanner.ca to get exact dates for each crop based on Ottawa's last frost date.

Direct Sowing Schedule

Early Spring (late March to early April)

• Peas — Direct sow as early as March 25–April 5; peas tolerate frost and prefer cool soil
• Spinach, arugula, lettuce — Sow from late March; grow in soil temperatures as low as 4°C
• Radishes — Sow from early April
• Carrots — Sow from mid-April when soil is workable

Pre-Last Frost (April 15 – May 5)

• Kale, Swiss chard — Transplant or direct sow; both handle light frost
• Broccoli, cabbage transplants — Harden off and transplant 2 weeks before last frost
• Beets — Direct sow mid-April through May

After Last Frost (May 10 onward)

• Beans — Direct sow after May 10; soil should be 15°C+
• Corn — Direct sow after May 10; needs 18°C+ soil
• Squash, pumpkins — Transplant or direct sow after May 10
• Cucumbers — Transplant seedlings after last frost

Transplanting Schedule

Ottawa vs. Toronto: Key Differences

Ottawa gardeners often assume they're on the same schedule as Toronto — they're not. Ottawa's last frost is 2–3 weeks later than Toronto's (Zone 6b), and its first frost arrives 1–2 weeks earlier. That adds up to roughly 3–4 fewer growing weeks.

• Don't follow Toronto planting guides without adjusting for Ottawa's Zone 5a dates
• Ottawa's growing season averages 148–155 days vs. Toronto's 165–175 days
• Varieties chosen for "southern Ontario" may need greenhouse assistance in Ottawa

Fall Planting

Ottawa's long fall (frost often not until October 5) makes a second planting season viable:

• Peas — Direct sow July 20–August 1 for a fall harvest
• Lettuce, spinach, arugula — Sow July 25–August 10 for fall crops
• Radishes — Sow August 1–20
• Kale — Transplant August 1 for fall harvest; frost improves flavour

Frost Protection

Ottawa springs are unpredictable — a warm April can give way to a May frost. Keep row covers handy through mid-May:

• Floating row cover — Protects to -3°C; keep on hand through May 10–20 window
• Season extenders (Wall-o-Waters, cloches) — Allow tomato transplanting 2–3 weeks earlier
• Cold frames — Ideal for Ottawa's shoulder seasons

Plan Your Ottawa Garden

MyGardenPlanner.ca is built for Canadian growing conditions, including Ottawa's Zone 5a. Use the planting dates for Ontario page or the calculator to build a personalized planting schedule for your specific Ottawa location.

Whether you're growing in the Glebe, Kanata, or across the river in Gatineau, accurate planting dates are the foundation of a productive garden.