When to Plant Lettuce in Fredericton, NB
Published: April 24, 2026 · Updated: April 27, 2026
The fastest cool-season crop — some varieties ready in 30 days. Lettuce must be timed to cool seasons as it bolts (goes to seed and turns bitter) in summer heat.
Fredericton's Canadian Zone 5b (USDA 5a) St. John River valley climate is continental with maritime influence. Warmer summers than coastal New Brunswick, colder winters. 151 frost-free days support a broad range of warm-season vegetables when timed carefully.
Lettuce Planting Calendar for Fredericton
Start seeds indoors: April 12–19
Transplant outdoors: April 12–22
Direct sow outdoors: March 29–April 8
Harvest window: May 12 – June 11
Minimum soil temperature: 4°C (40°F)
Days to harvest: 30–60 days
Sun requirement: Full sun to partial shade
Fall crop planting: August 27–September 6 (harvest September 26)
Fredericton Climate Notes
Fredericton's St. John River valley creates a warmer microclimate than surrounding uplands. The city has New Brunswick's most productive growing conditions for warm-season crops. Long daylight hours in June-July produce exceptional tomato and pepper quality.
Growing Tips for Lettuce
- Direct sow very shallowly — lettuce seeds need light to germinate; cover with just 1/8 inch of soil.
- Cut outer leaves 1 inch above the crown for "cut-and-come-again" harvests lasting weeks.
- Provide afternoon shade in warmer climates (Zones 7+) to extend the spring window before heat bolts plants.
- Fall lettuce is often better than spring — plants mature as temperatures cool, producing sweeter, crunchier heads.
Companion Planting in Fredericton
Pair lettuce with Carrot, Radish, Strawberry, Chive for mutual benefit. Avoid planting near Fennel, Celery, which compete with or inhibit lettuce growth.
Pests and Problems to Watch in Fredericton
The most common pest and disease pressure on lettuce in Fredericton comes from Aphids, Slugs, Cutworm, Leaf Miner. Floating row covers through the first 4–6 weeks after planting block adult pests from laying eggs, and a weekly scouting routine catches infestations before they damage the crop.
Other New Brunswick Cities
Frequently Asked Questions
When do I plant lettuce in Fredericton?
Fredericton's last spring frost is around May 10. Start seeds indoors April 12–19. Transplant outdoors April 12–22.
What Canadian hardiness zone is Fredericton?
Fredericton is in Canadian Zone 5b (USDA equivalent 5a). The St. John River valley continental maritime climate delivers 151 frost-free days from May 10 to October 8, which shapes every planting date in the local calendar.
How long is Fredericton's growing season?
Fredericton has 151 frost-free days — from May 10 in spring to October 8 in fall. That is more than enough time to finish a full lettuce crop (30–60 days to maturity) before the first fall frost.
Can I grow lettuce in containers in Fredericton?
Yes. Container growing on balconies and decks is practical in Fredericton — choose a 5-gallon or larger dark-coloured container to warm the root zone, use a high-quality potting mix, and water daily during hot summer weather. In milder climates, containers extend both spring and fall windows by several weeks.
What is the first fall frost in Fredericton?
Fredericton's average first fall frost is October 8. For a fall lettuce crop, plant around August 27–September 6 so plants mature before the first killing frost.