When to Plant Lettuce & Leafy Greens in Canada

Lettuce, spinach, arugula, and other leafy greens are the first crops Canadian gardeners can plant outside each spring — and with proper timing, you can harvest fresh greens from April through October. The secret is understanding that these are cool-season crops that prefer soil temperatures of 4–18°C (40–65°F). Hot summers work against lettuce, causing bolting (going to seed), so timing your sowings around the cool shoulder seasons is the key to continuous harvests.

When to Plant Lettuce by Zone

Lettuce seed germinates in soil as cool as 4°C (40°F) and tolerates light frost to about -3°C (27°F) once established. This makes it one of the earliest crops you can direct sow outdoors.

Zone 3 (Edmonton, Saskatoon, Northern Ontario)

• Direct sow (spring): May 1–20
• Fall sowing: Late July – early August
• Short season means one solid spring flush and one fall window. Choose fast-maturing leaf types (45 days or less).

Zone 5 (Ottawa, Kingston, Southern Ontario)

• Start indoors (spring): March 15–25
• Direct sow (spring): April 1–20 (as soon as soil is workable)
• Fall sowing: August 1–20
• Ottawa gardeners can often direct sow by April 1–5 in a cold frame, or April 15 in open ground. Succession sow every 2–3 weeks through May.

Zone 6 (Toronto, Niagara, Windsor)

• Start indoors (spring): March 5–15
• Direct sow (spring): March 25 – April 15
• Fall sowing: August 10–25
• Toronto has a long lettuce window. Spring plantings can often continue to late May before heat triggers bolting.

Zone 7 (Lower Mainland BC, Victoria)

• Direct sow (spring): February 15 – April 1 (under cover), March 15 – April 15 (open ground)
• Fall sowing: September 1–15
• BC's mild climate allows near year-round lettuce production. Fall plantings often overwinter with minimal protection.

Zone 8 (Metro Vancouver, southern Vancouver Island)

• Direct sow (spring): February 1 – April 1
• Winter sowing: Possible with cold frame or low tunnel
• Fall sowing: September 15 – October 1
• True year-round lettuce production is possible in zone 8 with basic season extension.

Greens Planting Quick Reference

Succession Sowing: The Key to Continuous Harvests

A single spring sowing gives you one big flush of lettuce — then it bolts in July heat. Succession sowing solves this:

• Sow a small batch every 2–3 weeks from April through mid-May (zone 5)
• Skip June–July for heat-sensitive varieties, or switch to bolt-resistant types
• Resume sowing in August for fall harvests

In zone 5, a well-timed succession schedule can deliver fresh greens from late April through November with minimal protection. The succession planting calculator at mygardenplanner.ca can help you map out your full sowing schedule automatically.

Extending the Season

Cold frames and low tunnels let you push lettuce 4–6 weeks earlier in spring and 4–6 weeks later in fall:

• A cold frame in Ottawa can produce lettuce from late March
• Low tunnels in Toronto can protect greens through November

Indoor starting: Start lettuce indoors 4–6 weeks before your last frost date under grow lights. Transplant as 3–4 week-old seedlings. Don't start too far ahead — overgrown lettuce seedlings become root-bound and stunt quickly.

Variety Selection for Canadian Gardens

Heat-tolerant (reduces summer bolting):

• Jericho (romaine) — excellent bolt resistance, widely available in Canada
• Nevada — crisp butterhead type, slow to bolt
• Black Seeded Simpson — classic leaf type, reliable across zones

Cold-tolerant (for early spring and fall):

• Winter Density — romaine × butterhead cross; overwinters in zone 7+
• Rouge d'Hiver — red romaine, tolerates frost well
• Merveille des Quatre Saisons — French heirloom, handles temperature swings

For zone 3–4 short seasons:

• Oak Leaf (green or red) — 45 days, consistent in variable temps
• Salad Bowl — loose-leaf mix, tolerates spring cold snaps well

Harvesting Greens

Cut-and-come-again: For leaf lettuce, harvest outer leaves and the plant continues producing for weeks. This works well for arugula, chard, kale, and all loose-leaf types.

Head lettuce: Harvest when the head is firm and full-sized. In hot weather, check daily — a day or two can mean the difference between peak flavour and bitter, bolted greens.

Plan Your Full Greens Schedule

Get your exact spring sowing dates for lettuce, spinach, and other greens with the planting date calculator at mygardenplanner.ca — enter your location and get personalized timing for every crop in your garden. You can also browse planting dates by province for zone maps and frost date tables for your area.