Lettuce has one of the shortest windows between "ready to harvest" and "too late to eat" of any garden vegetable. In warm weather, a head of romaine that looks perfect on Monday will be bitter and bolting by Saturday. This is not a failing of the crop — it is an argument for growing smaller amounts more frequently, so that every head is harvested at exactly the right moment.
Staggered lettuce plantings, spaced ten to fourteen days apart, produce a steady supply of salad greens from early spring until summer heat makes cool-season growing impractical, and again from late summer through the first hard frosts of fall. No single sowing is large enough to overwhelm the kitchen, and none is allowed to sit in the ground long enough to decline.
Understanding Lettuce Growth Stages
Lettuce passes through several stages, and the harvest window falls between the point of full size and the point of bolting. Understanding these stages helps with timing each succession correctly.
Germination and Seedling Stage
Lettuce germinates in 7 to 14 days at soil temperatures between 40°F and 75°F. Above 80°F, germination rates drop sharply — a problem for late-spring sowings. Pre-chilling seeds in a damp paper towel in the refrigerator for 24 hours before sowing can improve germination rates in warm conditions.
Vegetative Growth
After germination, lettuce grows steadily for 3 to 5 weeks. During this period it is tolerant of light frost and light shade. This is the phase during which most of the plant's energy goes into leaf production.
Harvest Window
Loose-leaf varieties are ready to pick in 30 to 45 days from sowing. Butterhead and romaine types take 55 to 75 days. The harvest window — from first-pick-ready to bolting — is 7 to 21 days depending on temperature. Cool weather extends this window; heat compresses it dramatically.
Bolting
Bolting is triggered by long days combined with warm temperatures. The plant shifts energy from leaf production to seed stalk formation. Flavor turns bitter quickly once bolting begins. For spring sowings in northern climates, the last viable sow date is typically 6 to 8 weeks before average daytime highs reach 80°F consistently.
Building a Spring Lettuce Succession
A spring succession should begin as early as the soil can be worked — often 6 to 8 weeks before last expected frost. Lettuce tolerates light frost, and early sowings in cool soil can be covered with row cover on nights below 26°F.
Sample Spring Schedule (Zone 6)
- March 20: First sowing — cold-hardy varieties (Winter Density, Forellenschluss)
- April 3: Second sowing — mixed leaf varieties
- April 17: Third sowing — mix of leaf and butterhead
- May 1: Fourth sowing — heat-tolerant varieties (Jericho, Nevada, Sierra)
- May 15: Final spring sowing — heat-tolerant varieties only
Each sowing covers a 3- to 4-foot row, or one 12-inch container for container gardeners. The first sowing is ready to harvest in late April, the second in mid-May, and so on. By the time the final spring sowing bolts in late June, the fall succession has been planned and seeds are ready.
Row Cover as a Season Extender
Lightweight row cover (0.55 oz/sq yd) protects early sowings from frost without significantly reducing light. It also excludes aphids and flea beetles, which target young lettuce. Remove row cover once temperatures consistently stay above 40°F during the day to allow pollinator access and prevent overheating.
Choosing Varieties for Spring Successions
Not all lettuce varieties bolt at the same rate. Building a spring succession with variety selection as well as sow-date spacing dramatically extends the harvest window.
Fast-Maturing Spring Varieties (30–45 days)
- Black Seeded Simpson: Classic loose-leaf, mild flavor, ready in 28 days
- Buttercrunch: Butterhead type, 55 days but very cold-tolerant for early sowings
- Tom Thumb: Mini butterhead, ideal for containers, 65 days
Heat-Tolerant Varieties for Late Spring
- Jericho: Romaine developed in hot climates, slow to bolt
- Nevada: Loose-leaf, exceptional heat tolerance
- Sierra: Batavian type, crisp even in warm weather
- Slobolt: Name says it all — among the slowest-bolting loose-leaf types
For gardeners also growing herbs, similar heat-tolerance principles apply. The herb garden guide covers basil and cilantro succession timing that coordinates well with lettuce rotations in the same beds.
The Summer Gap and When to Resume
In most climates, there is a summer window when outdoor lettuce production is not viable. In zone 6–7, this typically runs from mid-June through mid-August. During this period, use the bed space for heat-tolerant crops — beans, cucumbers, summer squash.
Resuming fall lettuce sowings requires working backward from the first expected hard frost (below 28°F). Lettuce needs 30 to 75 days to mature depending on variety, and it tolerates light frost but not hard freezes without protection. In zone 6, with a typical first hard frost around October 25:
- Last direct-sow date for loose-leaf: September 25 (30 days to maturity)
- Last direct-sow date for romaine: September 10 (45 days)
- Last direct-sow date for butterhead: September 5 (50 days)
Building a Fall Lettuce Succession
Fall successions run in reverse — from the last viable sow date back toward late summer. The first fall sowing often coincides with the hottest part of the season, which creates germination challenges. Start fall lettuce indoors or in a shaded location, then transplant seedlings to the garden when temperatures moderate.
Sample Fall Schedule (Zone 6)
- August 10: Start seedlings indoors (transplant in 3 weeks)
- August 20: Direct sow heat-tolerant varieties with shade cloth
- September 1: Direct sow without shade protection
- September 15: Final sowing — fast-maturing varieties only
Fall lettuce grows more slowly than spring lettuce as days shorten and temperatures drop, so add 10 to 14 days to variety maturity times when calculating fall harvest dates.
Integrating Lettuce Successions Into Raised Beds
Raised beds make lettuce succession planting easier because the loose, well-drained soil allows quick replanting after each harvest. The key is leaving narrow succession strips — 4 to 6 inches wide — between other plantings, so lettuce can occupy gaps in the bed without requiring dedicated rows. The raised beds complete guide covers bed layout strategies that accommodate succession strips alongside longer-season crops.
After each lettuce harvest, clear the residue, scratch the surface, and direct-sow the next succession in the same spot. Loose bed soil requires no additional preparation between plantings in most cases. Adding a thin layer of compost — a quarter inch — before re-sowing replenishes nutrients quickly.
Frequently Asked Questions
How much lettuce should I sow in each succession?
For a two-person household, a 3-foot row of lettuce — roughly 12 to 18 transplants or thinned seedlings — provides salad greens every two to three days for two weeks. Larger households should scale up proportionally, or add a second row to each sowing.
Can I mix lettuce varieties in a single sowing?
Yes. Seed mixes labeled "mesclun" or "salad mix" combine varieties with different maturity rates, providing a range of flavors and textures from a single sowing. For succession purposes, treat the mix as a single unit and replace it on the standard interval.
Why does my lettuce germinate poorly in summer?
Lettuce enters dormancy (thermodormancy) at soil temperatures above 77°F. To improve summer germination, pre-chill seeds in the refrigerator for 24 hours before sowing, sow in the evening so seeds spend their first night in cooler conditions, and mist the soil surface twice daily to prevent crusting.
How do I keep fall lettuce going after frost?
Row cover extends the season by 4 to 6°F. Cold frames or low tunnels can protect lettuce through light frosts down to 25°F. Varieties like Arctic King and Winter Marvel are bred for cold-hardiness and can survive brief dips to 20°F under cover.
Is cut-and-come-again harvesting the same as succession planting?
No — though both extend the harvest. Cut-and-come-again harvesting takes outer leaves from individual plants repeatedly over several weeks. Succession planting staggers entirely new sowings at regular intervals. The two approaches complement each other: cut-and-come-again extends the life of each sowing, while succession planting ensures a new planting is always maturing to replace the current one.