đ„ŹWhen to Plant Lettuce in USDA Zone 3b (2026 Guide)
Cool-season green that can go out weeks before the last frost. Here is the cool-season planting schedule for lettuce in zone 3b (covering areas like northern Maine, Bemidji MN). All dates are based on 2026 frost data for your zone.
Start Seeds Indoors
Apr 17
Direct sow or transplant
Apr 24
Harvest From
Jun 8
Because lettuce is a cool-season crop, it tolerates light frost and can go out around Apr 24, before zone 3b's average last frost on May 15.
- Type: Cool-season
- Method: Direct sow or transplant
- Days to harvest: 45
- Spacing: 8" apart
- Sun: Full sun to part shade
- Zone 3b frost: May 15 â Sep 20
- Season length: ~128 days
- Companions: carrot, radish, cucumber
Growing lettuce in zone 3b
Zone 3b has an average last spring frost around May 15 and a first fall frost around Sep 20, giving roughly 128 frost-free growing days. That window comfortably fits lettuce's 45-day cycle, with room for a second succession planting if you time it right.
Get a head start by sowing seeds indoors around Apr 17, roughly 4 weeks before your last frost. Move the seedlings outside around Apr 24. Give each plant about 8 inches of space in full sun to part shade.
Zone 3b specific growing notes
In zone 3b (northern Maine, Bemidji MN), your 128-day growing season means lettuce should be one of your first spring plantings. Cool-season crops thrive in the mild part of your growing window. Monitor soil temperature â lettuce germinates best when soil is 40-75°F.
Your first fall frost around Sep 20 means your last possible harvest is roughly late Sep. For a continuous supply, consider succession planting every 2-3 weeks from Apr 24 through mid-season.
Pro tip for lettuce
Use cut-and-come-again harvestingâpick outer leaves when 3-4 inches long and the center keeps producing for weeks. For full heads, harvest in the morning when leaves are crispest.
Troubleshooting lettuce
Bolting (sending up a flower stalk) happens when soil temperatures exceed 70°F. Leaves turn bitter once bolting starts. Plant in afternoon shade and choose slow-bolt varieties like 'Buttercrunch' for summer.
Growing lettuce in containers
Ideal for shallow containersâroots only go 4-6 inches deep. Window boxes, salad trays, even repurposed gutters work perfectly. One 12-inch pot yields salad for two people.
Can you plant lettuce twice a year?
Absolutelyâsuccession sow every 2-3 weeks for continuous harvest. In zones 5+, sow spring crops until late May, then resume in late August for fall. Lettuce germinates poorly above 80°F soil.
Frequently asked questions
When should I plant lettuce in zone 3b?
Direct sow or transplant around Apr 24. If starting from seed indoors, sow around Apr 17. Because lettuce is a cool-season crop, it tolerates light frost and can go out around Apr 24, before zone 3b's average last frost on May 15.
How long does lettuce take to grow in zone 3b?
About 45 days from sowing to first harvest. A Apr 24 planting in zone 3b is typically ready to pick from around Jun 8. Zone 3b has about 128 frost-free days â plenty of time for a second succession planting.
How far apart should I space lettuce?
Space lettuce about 8 inches apart in full sun to part shade. This gives each plant enough room for roots to spread and leaves to catch sunlight without competing.
What is the best tip for growing lettuce?
Use cut-and-come-again harvestingâpick outer leaves when 3-4 inches long and the center keeps producing for weeks. For full heads, harvest in the morning when leaves are crispest.
What are common problems with lettuce and how do I fix them?
Bolting (sending up a flower stalk) happens when soil temperatures exceed 70°F. Leaves turn bitter once bolting starts. Plant in afternoon shade and choose slow-bolt varieties like 'Buttercrunch' for summer.
Can I grow lettuce in a container?
Ideal for shallow containersâroots only go 4-6 inches deep. Window boxes, salad trays, even repurposed gutters work perfectly. One 12-inch pot yields salad for two people.
Can I plant a second crop of lettuce for fall harvest?
Absolutelyâsuccession sow every 2-3 weeks for continuous harvest. In zones 5+, sow spring crops until late May, then resume in late August for fall. Lettuce germinates poorly above 80°F soil.
What grows well next to lettuce?
Good companion plants for lettuce are carrot, radish, cucumber. Avoid planting near warm-season crops that compete for space and nutrients. Lettuce also benefits from crop rotation â do not plant it in the same spot year after year.