When to Plant Lettuce in Washington
Published: April 21, 2026
Washington gardeners in Zone 4b have a 21-week frost-free window for lettuce (May 7 to October 1). Cool-season crops like lettuce do well here because the short, cool summers match the plant's temperature preferences naturally. This guide gives exact dates for Washington based on your local frost calendar.
Lettuce Planting Dates for Washington
| Start seeds indoors | April 9–16 |
| Last frost (average) | May 7 |
| Transplant outdoors | April 9–19 |
| Direct sow outdoors | March 26–April 5 |
| Expect first harvest | May 9 – June 8 |
| Fall crop start | August 20–30 |
| Fall harvest | September 19 |
| First fall frost (average) | October 1 |
Growing Lettuce in Washington's Climate
Washington's cold Zone 4b climate is close to ideal for lettuce. The cool springs and moderate summers match the plant's natural temperature preferences, producing crisp, sweet, slow-bolting harvests that hot-climate gardeners cannot grow.
The fall lettuce crop in Washington is often better than the spring crop. Plants mature as temperatures cool in September and October, concentrating sugars and tightening heads or roots. Light frost can improve flavor; hard frost signals harvest time.
Common lettuce pests to watch for in Washington include Aphids and Slugs. The first line of defense is companion planting: Carrot and Radish planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Lettuce Garden Calendar for Washington
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | Direct sow seeds | Sow seeds 1/4–1/2 inch deep, 8 inches apart |
| April | Transplant outdoors | Soil temp must be 40°F+; nighttime lows above 50°F |
| May ← | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| June | — | Dormant season |
| July | — | Dormant season |
| August | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| September | — | Dormant season |
| October | First frost approaches | Harvest remaining lettuce; cover plants on frost nights |
| November | — | Dormant season |
| December | — | Dormant season |
Lettuce Growing Tips for Washington Gardeners
- •Direct sow very shallowly — lettuce seeds need light to germinate; cover with just 1/8 inch of soil.
- •Cut outer leaves 1 inch above the crown for "cut-and-come-again" harvests lasting weeks.
- •Washington's short growing season means start seeds indoors under grow lights — don't rely on windowsill light which produces leggy, weak seedlings that struggle outdoors.
- •Cover young transplants with floating row covers for the first 2–3 weeks outside. The 3–5°F of protection reduces frost damage risk and accelerates early growth.
- •Provide afternoon shade in warmer climates (Zones 7+) to extend the spring window before heat bolts plants.
Companion Planting for Lettuce in Washington
In Washington's cold climate, planting lettuce with Carrot and Radish helps deter pests and improve soil. Avoid planting near Fennel and Celery, which inhibit lettuce growth through root chemistry or shared pest pressure. See the full lettuce companion planting guide for the complete list.
Lettuce Planting Dates by City in Washington
Top cities in Washington — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant lettuce in Washington?
In Washington (Zone 4b), start lettuce seeds indoors around April 9–16 and transplant outdoors around April 9–19 — 4 weeks before the state's average last frost of May 7.
What is the last frost date in Washington?
Washington's average last frost date is May 7 in the state's most common Zone 4b. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow lettuce year-round in Washington?
lettuce is a cool-season crop in Washington, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What lettuce varieties grow best in Washington?
For Washington's Zone 4b, Cold-tolerant Buttercrunch, Winter Density, and Arctic King overwinter with protection.
When do I start lettuce seeds indoors in Washington?
Start lettuce seeds indoors in Washington around April 9–16, which is 4 weeks before the state's average last frost of May 7. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.