đ„ŹWhen to Plant Lettuce in USDA Zone 10b (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 10b (covering areas like Key West FL, coastal So-Cal). All dates are based on 2026 frost data for your zone.
Start Seeds Indoors
Dec 18
Direct sow or transplant
Dec 25
Harvest From
Feb 8
Because lettuce is a cool-season crop, it tolerates light frost and can go out around Dec 25, before zone 10b's average last frost on Jan 15.
- Type: Cool-season
- Method: Direct sow or transplant
- Days to harvest: 45
- Spacing: 8" apart
- Sun: Full sun to part shade
- Zone 10b frost: Jan 15 â Dec 31
- Season length: ~350 days
- Companions: carrot, radish, cucumber
Growing lettuce in zone 10b
Zone 10b has an average last spring frost around Jan 15 and a first fall frost around Dec 31, giving roughly 350 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 Dec 18, roughly 4 weeks before your last frost. Move the seedlings outside around Dec 25. Give each plant about 8 inches of space in full sun to part shade.
Zone 10b specific growing notes
In zone 10b (Key West FL, coastal So-Cal), your 350-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 Dec 31 means your last possible harvest is roughly late Dec. For a continuous supply, consider succession planting every 2-3 weeks from Dec 25 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 10b?
Direct sow or transplant around Dec 25. If starting from seed indoors, sow around Dec 18. Because lettuce is a cool-season crop, it tolerates light frost and can go out around Dec 25, before zone 10b's average last frost on Jan 15.
How long does lettuce take to grow in zone 10b?
About 45 days from sowing to first harvest. A Dec 25 planting in zone 10b is typically ready to pick from around Feb 8. Zone 10b has about 350 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.