Montréal Planting Calendar 2026 — Zone 5b Frost Dates & Seed Starting Guide

Montréal sits primarily in hardiness Zone 5b, with the last spring frost arriving around May 4 and the first fall frost typically around October 7. That gives most island gardeners roughly 155 frost-free days — enough for a wide range of vegetables when you start seeds indoors on schedule.

Note: Some south shore communities (Longueuil, Brossard, Saint-Lambert) sit in Zone 6a, with a last frost as early as April 24. Check the frost dates tool at MyGardenPlanner.ca for your specific postal code.

Montréal Frost Dates 2026

Source: Agriculture Canada Plant Hardiness Zone Map.

Montréal Indoor Seed Starting Schedule

Start these crops under grow lights 6–10 weeks before your May 4 last frost:

Montréal Direct Seeding Schedule (Outdoors)

Cool-Season Crops — Sow April 14 onward (3 weeks before last frost)

Peas, spinach, lettuce, mâche, kale, arugula, Swiss chard, radishes, carrots, beets, and parsnips. Soil should be at least 5°C.

Warm-Season Crops — Sow May 17 onward (soil above 15°C)

Bush beans, pole beans, corn, zucchini, squash, cucumbers, and sunflowers.

Month-by-Month Montréal Planting Calendar

February

• Start peppers, eggplant, leeks, celery, and onions under grow lights
• 14–16 hours of light daily required for strong seedlings

March

• Start tomatoes late March for a May 24–June 1 transplant
• Start broccoli and cabbage late March for early May hardening

April

• Early–mid April: Direct sow peas and hardy greens once soil thaws to 5°C
• Late April: Harden off brassica transplants in a cold frame or sheltered spot outdoors

May — Montréal's Critical Planting Month

• May 1–7: Transplant hardened broccoli, cabbage, and onion seedlings after last frost watch
• May 17–24: Direct sow beans, corn, squash, and zucchini once soil reaches 15°C
• May 24–June 1: Transplant tomatoes after thorough hardening — nights must reliably stay above 7°C

June

• Transplant peppers, basil, and eggplant once nights stay above 10°C
• Succession-plant lettuce and radishes every 2 weeks
• Sow a second round of beans for August harvest

July–August

• Harvest spring crops; sow fall kale, spinach, and arugula mid-July to early August
• Monitor for tomato blight — Montréal's humid summers favour early blight development

September–October

• Harvest main-season crops before the October 7 first frost
• Use row covers to extend peppers and tomatoes 2–3 extra weeks

What Grows Best in Montréal

Zone 5b supports most cool-season vegetables and, with proper timing, most warm-season crops:

Consistently productive: Tomatoes, peppers (with a long head start), cucumbers, zucchini, beans, corn, garlic, all brassicas, root vegetables, and leafy greens.

Worth trying: Short-season melons (Alvaro, Petit Gris de Rennes) on a south-facing bed with black plastic mulch. Start them indoors in early May; transplant after June 1.

Québec favourites: Fève des marais (broad beans), céleri-rave (celeriac), poireau (leeks) — all well-suited to Montréal's cool springs and moderate summers.

Montréal Microclimate Notes

• Urban heat island: Downtown Montréal can run half a zone warmer than Agriculture Canada maps suggest — excellent for heat-loving crops.
• Mont Royal: Properties on the north side of Mont Royal get less afternoon sun and may see slightly later springs.
• River exposure: Open properties along the St. Lawrence can see damaging late frosts from cold air moving off the water — keep a row cover on hand until May 15.

Plan Your Montréal Garden

Use the MyGardenPlanner.ca planting date calculator to enter your specific Montréal postal code and get a custom seed starting and transplant schedule. The Home Gardener plan includes a full season planner with bed maps and AI-assisted crop planning — designed for Canadian growing zones like Zone 5b.