CANADA PLANTING GUIDE

Growing Lettuce in Canada — Bolt-Resistant Varieties, Succession Sowing & Year-Round Strategies

Best varieties by season (heat-tolerant Jericho + Nevada, cold-hardy Winter Density + Arctic King), succession sowing every 2-3 weeks, beating summer bolting with shade and timing, fall and zone-permitting overwintering crops, and indoor lettuce year-round.

GrowersGuide.ca is reader-supported. When you buy through links on this page, we may earn an affiliate commission — at no extra cost to you. Learn more.

Lettuce is the fastest return in any Canadian garden — 25 days from sowing to first cut-and-come-again harvest with looseleaf varieties. The challenge isn't growing it; it's keeping a continuous supply through the Canadian summer when heat above 24°C triggers bolting and turns leaves bitter overnight. The answer is succession sowing (a short new row every 2-3 weeks), variety selection by season, and afternoon shade in July-August.

What follows is lettuce growing for actual Canadian conditions: the four lettuce types, variety choice by season, the succession-sowing system, beating summer heat, the fall + overwintering window in zones 6+, cut-and-come-again harvest, year-round indoor growing, and the 5 most common Canadian lettuce problems.

The Four Lettuce Types

Best Canadian Lettuce Varieties by Season

Sowing Window by Canadian Region

Succession Sowing — The Continuous-Harvest System

A single lettuce planting bolts in 4-6 weeks. To eat lettuce continuously from May through October you need 8-10 staggered sowings. This is the single highest-return lettuce decision — more important than variety, soil, or watering.

• Cadence: a short new row every 14 days, spring through early August. 30-60 cm per sowing.
• Spring (cool soil 4-15°C): Buttercrunch, Black Seeded Simpson, Salad Bowl, Red Sails.
• Late spring through summer (warming soil 15-24°C): switch to Jericho romaine, Nevada Batavian, Slobolt — the heat-tolerant set.
• Heat-peak weeks (soil above 24°C; usually mid-July to mid-August): skip outdoor sowing entirely. Move to an east-facing shaded bed or indoor LED setup.
• Fall sowing (cool soil returning): switch to Winter Density, Arctic King, Rouge d'Hiver, Brune d'Hiver — the cold-hardy set.
• Indoor backup year-round: a 30-50 W LED over a 60 cm shelf yields cut-and-come-again greens for 2 people on a 25-30 day cycle.

Beating Summer Bolting

Bolting (flowering, then bitter leaves) is triggered by long days plus soil/air temperature above 24°C. Once bolting starts the lettuce is done within a week. Six strategies in priority order:

1. Heat-tolerant varieties for summer sowings: Jericho romaine, Nevada Batavian, Slobolt, Sierra, Sea of Red.
2. Afternoon shade: plant on the east side of taller crops (tomatoes, peppers, pole beans), or use 30% shade cloth 11am-5pm.
3. Heavy mulch: 5-7 cm of straw or shredded leaves keeps soil 5-8°C cooler. See Mulching in Canada.
4. Consistent water: lettuce has shallow roots; one dry spell triggers bolting. Light watering daily in heat. See Watering in Canada.
5. Sow early morning or late evening: hot daytime soil delays germination and triggers premature bolting.
6. Cut-and-come-again at the looseleaf stage: the plant's growing point stays small and the bolting signal is delayed.
7. Skip July sowing: in most of Canada, pause outdoor sowing mid-July through mid-August. Resume late August for fall harvest.

Cut-and-Come-Again Harvest

Harvest the outer leaves while leaving the central crown intact. The plant continues producing new leaves for 4-6 weeks, yielding 4-6× more than a single full-head harvest.

• When: looseleaf or butterhead plants 12-15 cm tall.
• How: scissors or sharp knife — cut the largest 3-4 outer leaves per plant at the base. Leave the smaller central leaves untouched.
• Cycle: re-harvest the same plant every 5-7 days.
• Best varieties: Black Seeded Simpson, Salad Bowl, Red Sails, Lollo Rossa, mesclun mix, any looseleaf or butterhead.
• Less effective with: romaine, crisphead — these need to fully head up.
• Stop cutting when the plant sends up a central flower stalk — harvest the whole plant immediately while leaves are still sweet.

Year-Round Indoor Growing

Lettuce is the easiest indoor crop in Canada. A small inexpensive LED over a 60 cm shelf yields year-round salad for 2 people.

• Light: 30-50 W full-spectrum LED, 30-40 cm above plants, 16-18 hours per day. Lettuce uses 75-100 PPFD — far less than fruiting crops, so a small inexpensive LED works. See Grow Light Calculator.
• Temperature: 16-22°C, cool windowsill ideal.
• Substrate + container: any potting mix or coco coir. 15 cm deep for full heads, 8-10 cm for cut-and-come-again.
• Schedule: sow every 14 days. Germination 5-7 days. First cut-and-come-again 25-30 days. Full heads 50-65 days.
• Varieties: Black Seeded Simpson, Buttercrunch, Salad Bowl, Tom Thumb (mini), mesclun mix, any looseleaf.
• Hydroponics (optional): deep water culture or NFT compresses harvest to 30 days.

Where to Buy Canadian Lettuce Seed

• West Coast Seeds (Delta, BC) — broad selection including heat-tolerant + overwintering varieties.
• Veseys Seeds (Charlottetown, PEI) — ships nationally.
• William Dam Seeds (Dundas, ON) — Ontario standard.
• Salt Spring Seeds (BC) — heirloom + open-pollinated specialist.
• Solana Seeds (Quebec) — French + Quebec heirlooms (Brune d'Hiver, Rouge d'Hiver).
• Eagle Creek Farms (Bowden, AB) — Prairie-adapted.

5 Most Common Canadian Lettuce Problems

Related Canadian Guides