Hamilton Ontario Planting Calendar 2026 — Zone 6a Frost Dates & Seed Guide

Hamilton, Ontario sits in hardiness Zone 6a (Hamilton Mountain and west end) to Zone 6b (downtown and lower city), giving most gardeners a last spring frost around April 24 and a first fall frost around October 19. That's roughly 178 frost-free days — one of the longest growing seasons in inland Ontario.

Use the frost date tool at MyGardenPlanner.ca to confirm exact frost dates for your specific Hamilton postal code, then use this calendar to build your planting schedule.

Hamilton Frost Dates 2026

Source: Agriculture Canada Plant Hardiness Zone Map.

Hamilton Indoor Seed Starting Schedule

Start these crops under grow lights 6–10 weeks before your last frost date of April 24:

Hamilton Direct Seeding Schedule (Outdoors)

Cool-Season Crops — Sow April 3–17 (soil above 5°C)

Peas, spinach, lettuce, kale, Swiss chard, arugula, radishes, carrots, beets, parsnips, and turnips.

Warm-Season Crops — Sow May 10–24 (soil above 15°C)

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

Month-by-Month Hamilton Planting Calendar

February

• Start peppers, eggplant, leeks, celery, and onions under grow lights
• Aim for 14–16 hours of light per day

March

• Start tomatoes mid-March for a May 17–24 transplant date
• Start broccoli and cabbage mid-March for April hardening

April

• Early April: Direct sow peas, spinach, and carrots once soil reaches 5°C
• Mid April: Harden off brassica transplants in a cold frame or sheltered spot
• Late April (after April 24): Last average frost — watch overnight lows carefully

May — Main Planting Month

• May 1–10: Transplant hardened broccoli, cabbage, and onion seedlings
• May 10–17: Direct sow beans, corn, and squash once soil reaches 15°C
• May 17–24: Transplant tomatoes and peppers after 7–10 days of hardening off
• Victoria Day weekend (May 19): Traditional Hamilton planting date for warm-season crops

June

• Succession-plant lettuce, beans, and radishes every 2–3 weeks
• Transplant basil and eggplant once nights stay above 10°C

July–August

• Harvest spring crops; sow fall kale, spinach, and lettuce by late July
• Plant second succession of beans for a September harvest

September–October

• Use row covers to extend tomato and pepper harvest past first frost
• Direct sow spinach under a cold frame for late-fall harvest

What Grows Best in Hamilton

Zone 6 is one of the most productive climates for Ontario vegetable gardens:

Reliable producers: Tomatoes, peppers, cucumbers, zucchini, beans, corn, winter squash, garlic, all brassicas, leafy greens.

Worth trying: Short-season melons (Sugar Baby, Alvaro), sweet potatoes (Zone 6 warmth is borderline ideal), eggplant (faster varieties like Patio Baby or Orient Express).

Hamilton Microclimate Notes

• The Escarpment: The Mountain sits in Zone 6a. Cold air drains downslope — the lower city warms faster in spring.
• Lake Ontario proximity: Hamilton Harbour moderates temperatures slightly — expect later fall frosts in the lower city compared to the Mountain.
• Urban heat island: Downtown Hamilton can push effective zone up half a zone — ideal for heat-loving crops like peppers and eggplant.

Plan Your Hamilton Garden

Use the free planting calculator at MyGardenPlanner.ca to build a custom schedule for your Hamilton address. The Home Gardener plan adds a full season planner with bed maps, crop tracking, and AI-assisted planning — built for Canadian zones like Zone 6.