When to Plant Lettuce in Wisconsin
Published: April 21, 2026
Wisconsin gardeners in Zone 5a have a 26-week frost-free window for lettuce (April 15 to October 15). 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 Wisconsin based on your local frost calendar.
Lettuce Planting Dates for Wisconsin
| Start seeds indoors | March 18–25 |
| Last frost (average) | April 15 |
| Transplant outdoors | March 18–28 |
| Direct sow outdoors | March 4–14 |
| Expect first harvest | April 17 – May 17 |
| Fall crop start | September 3–13 |
| Fall harvest | October 3 |
| First fall frost (average) | October 15 |
Dates above assume Zone 5a, the most common zone in Wisconsin. Gardeners in cooler Milwaukee (Zone 5a) plant 1–2 weeks later; warmer Racine (Zone 5b) can plant 1–2 weeks earlier.
Growing Lettuce in Wisconsin's Climate
Wisconsin's cold Zone 5a 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 Wisconsin 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 Wisconsin 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 Wisconsin
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | Transplant outdoors | Soil temp must be 40°F+; nighttime lows above 50°F |
| April | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | — | Dormant season |
| August | — | Dormant season |
| September | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| October | First frost approaches | Harvest remaining lettuce; cover plants on frost nights |
| November | — | Dormant season |
| December | — | Dormant season |
Lettuce Growing Tips for Wisconsin 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.
- •Wisconsin'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 Wisconsin
In Wisconsin'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 Wisconsin
Top cities in Wisconsin — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant lettuce in Wisconsin?
In Wisconsin (Zone 5a), start lettuce seeds indoors around March 18–25 and transplant outdoors around March 18–28 — 4 weeks before the state's average last frost of April 15.
What is the last frost date in Wisconsin?
Wisconsin's average last frost date is April 15 in the state's most common Zone 5a. 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 Wisconsin?
lettuce is a cool-season crop in Wisconsin, 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 Wisconsin?
For Wisconsin's Zone 5a, Cold-tolerant Buttercrunch, Winter Density, and Arctic King overwinter with protection.
When do I start lettuce seeds indoors in Wisconsin?
Start lettuce seeds indoors in Wisconsin around March 18–25, which is 4 weeks before the state's average last frost of April 15. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.