Lettuce planting guide
When to plant lettuce
Lettuce grows best in cool weather. For spring, count backward from the day you plan to move seedlings outside. For fall, count backward from your usual first frost.
Spring transplants
4 weeks indoors
Calculate from the transplant date you plan to use.
Fall seeds outdoors
3 months before frost
Count backward from the usual first fall frost date.
Seed depth
1/4–1/2 inch
Prepare a smooth seedbed because lettuce seed is very small.
Soil pH
6.0–6.8
Use well-drained soil that still retains moisture.
Lettuce timing planner
Calculate from the date that matches your crop
For spring, enter the day you plan to move seedlings outside. For fall, enter your usual first frost date. The two plans count from different dates.
Spring options
Move seedlings or plant seeds outdoors
Start seedlings indoors about four weeks before moving them outside. You can also plant seeds directly outdoors once the soil is no longer frozen or too wet to work.
Fall option
Work backward from first frost
For a fall crop, plant seeds outdoors about three months before your usual first fall freeze. Use the frost calculator to choose a middle estimate or a more cautious date.
Estimate my first fall freeze →Why lettuce has its own calculator
Spring seedlings and fall crops count from different dates. This calculator keeps those two plans separate and follows the lettuce-specific university guide.
Planting and heat-risk checks
Spacing
For full-size leaf or head lettuce, the source lists 10–12 inches between plants. Mini heads are listed at 6–8 inches. Keep rows at least 18 inches apart.
Cool-weather target
The reviewed guide describes ideal conditions around a 50°F nighttime low and no more than a 68°F daytime high.
Early flowering (bolting)
Long days, intense light and heat can make lettuce flower early and taste bitter. Harvest spring lettuce before conditions become hot and dry.
Water
The source calls for about 1 inch of rainfall or irrigation per week and notes that shallow roots make consistent moisture important.