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.

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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.

🌱 Feeding your lettuce? See which crops are heavy vs light feeders in the Canadian vegetable fertilizer chart (NPK by crop), then dial in exact rates with the free fertilizer calculator.

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.

Sources: lettuce cut-and-come-again harvest — common gardening practice; consistent with this site’s growing-lettuce guide.

🔄 Free to reuse — please credit GrowersGuide.ca with a link.

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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