đ„ŹWhen to Plant Lettuce in USDA Zone 6a (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 6a (covering areas like St. Louis MO, Philadelphia PA). All dates are based on 2026 frost data for your zone.
Start Seeds Indoors
Mar 23
Direct sow or transplant
Mar 30
Harvest From
May 14
Because lettuce is a cool-season crop, it tolerates light frost and can go out around Mar 30, before zone 6a's average last frost on Apr 20.
- Type: Cool-season
- Method: Direct sow or transplant
- Days to harvest: 45
- Spacing: 8" apart
- Sun: Full sun to part shade
- Zone 6a frost: Apr 20 â Oct 15
- Season length: ~178 days
- Companions: carrot, radish, cucumber
Growing lettuce in zone 6a
Zone 6a has an average last spring frost around Apr 20 and a first fall frost around Oct 15, giving roughly 178 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 Mar 23, roughly 4 weeks before your last frost. Move the seedlings outside around Mar 30. Give each plant about 8 inches of space in full sun to part shade.
Zone 6a specific growing notes
In zone 6a (St. Louis MO, Philadelphia PA), your 178-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 Oct 15 means your last possible harvest is roughly late Oct. For a continuous supply, consider succession planting every 2-3 weeks from Mar 30 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 6a?
Direct sow or transplant around Mar 30. If starting from seed indoors, sow around Mar 23. Because lettuce is a cool-season crop, it tolerates light frost and can go out around Mar 30, before zone 6a's average last frost on Apr 20.
How long does lettuce take to grow in zone 6a?
About 45 days from sowing to first harvest. A Mar 30 planting in zone 6a is typically ready to pick from around May 14. Zone 6a has about 178 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.