When To Plant Lettuce In Wisconsin

If you’re a gardener in Wisconsin, knowing when to plant lettuce is the key to a long, productive harvest. This guide will cover the optimal spring and fall planting windows to help you succeed.

Lettuce is a cool-season champion, but our Wisconsin climate with its late frosts and early freezes requires careful timing. Getting it right means crisp salads for months; getting it wrong often leads to bitter, bolted plants. Let’s break down the schedule so you can enjoy lettuce from your garden almost all year.

This simple schedule is your starting point. Always adjust for your specific location and the year’s unique weather patterns.

Spring Planting: Sow seeds directly in the garden 2 to 4 weeks before your last average spring frost date. For most of Wisconsin, this is between late April and mid-May.
Fall Planting: Sow seeds directly in the garden 6 to 8 weeks before your first average fall frost date. For most areas, this means planting between early August and early September.

Understanding Your Wisconsin Frost Dates

Frost dates are your best friend for lettuce planting. Since Wisconsin’s climate varies, here’s a general guide:

Southern Wisconsin (Madison, Milwaukee): Last spring frost around May 1-15. First fall frost around October 1-15.
Central Wisconsin (Wausau, Stevens Point): Last spring frost around May 15-25. First fall frost around September 20-30.
Northern Wisconsin (Eau Claire, Superior): Last spring frost around May 25 – June 10. First fall frost around September 10-25.

Check with your local UW Extension office for the most precise dates in your county. Remember, these are averages, so watch the forcast each season.

Spring Planting: A Step-by-Step Guide

Spring planting is all about working with cold soil and unpredictable weather. The goal is to get lettuce growing during the cool days of spring before the summer heat arrives.

Prepare the Soil: As soon as the ground is workable, amend it with compost. Lettuce likes loose, fertile, well-draining soil with a neutral pH.
Sow Seeds: Plant seeds 1/4 inch deep, spacing them about 1 inch apart in rows 12-18 inches apart. You can sow them thicker and thin later for baby greens.
Protect from Cold: Use row covers or cold frames if a hard frost is expected after your seedlings emerge. This protection can also warm the soil slightly.
Thin Seedlings: Once they have a few true leaves, thin leaf lettuce to 4-6 inches apart and head lettuce to 8-12 inches apart. The thinnings are delicious in salads!
Water Consistently: Keep the soil evenly moist, not soggy. Mulch lightly to retain moisture and suppress weeds.

Best Lettuce Varieties for Wisconsin Spring

Cold-Tolerant Starters: ‘Black Seeded Simpson’, ‘Winter Density’, ‘Buttercrunch’.
Slower to Bolt: ‘Jericho’, ‘Sierra’, ‘Nancy’.

Fall Planting: The Secret for Superior Harvests

Many gardeners find fall lettuce even better than spring. The soil is warm for quick germination, and as days cool, the lettuce grows sweet and tender without bolting.

Calculate Your Date: Find your first fall frost date. Count back 6-8 weeks for direct seeding. For transplants, start seeds indoors 2-3 weeks earlier than that.
Beat the Heat at Seeding: Sow seeds in late summer when soil is hot. Provide light shade (with a board or shade cloth) until seeds sprout to keep the soil cool and moist.
Water Frequently: Germinating seeds in August heat need daily attention. Don’t let the seedbed dry out.
Fertilize Lightly: A light application of a balanced fertilizer at planting will support strong growth as temperatures drop.
Extend the Season: As frosts arrive, use row covers, cold frames, or even a simple low tunnel. Many lettuce varieties can survive hard freezes with protection, allowing harvests into December.

Best Lettuce Varieties for Wisconsin Fall

Fast Maturing: ‘Salad Bowl’, ‘Tango’, ‘Red Sails’.
Cold-Hardy Champions: ‘Rouge d’Hiver’, ‘Winter Marvel’, ‘Arctic King’.

Pro Tips for Year-Round Lettuce

With a few tricks, you can push your harvest window even further.

Succession Planting is Essential

Don’t plant all your seeds at once. For a continuous supply, sow a new short row or block every 10-14 days throughout the spring and fall planting windows. This way, you’ll always have lettuce at the perfect stage for picking.

Managing Heat and Bolting

Lettuce “bolts” (sends up a flower stalk) in response to long days and heat, becoming bitter. To slow bolting in late spring:

Choose bolt-resistant varieties.
Plant in a spot with afternoon shade.
Keep soil consistently moist with mulch.
Harvest leaves in the morning when they are most crisp.

Container and Indoor Growing

If garden space is limited, lettuce grows wonderfully in pots on a patio or balcony. You can also grow it indoors under simple grow lights during the deepest winter months for a fresh, homegrown treat.

Common Problems and Simple Solutions

Even with perfect timing, a few issues can pop up.

Slugs and Snails: They love tender lettuce. Use organic slug bait, beer traps, or hand-pick in the evening.
Aphids: A strong spray of water from the hose often knocks them off. Insecticidal soap is a effective follow-up.
Tipburn: Brown edges on leaves is often due to uneven watering or a calcium deficiency. Maintain consistent soil moisture.

FAQ: Lettuce Planting in Wisconsin

Can I plant lettuce in summer in Wisconsin?

It’s very challenging. Most lettuce varieties struggle with our summer heat and long days, leading to quick bolting. For summer harvest, try heat-resistant types like ‘Sierra’ or ‘Jericho’ in partial shade, but your main crops should be spring and fall.

How early can I start lettuce seeds indoors for spring?

Start seeds indoors 4-6 weeks before you plan to transplant them outside. Harden off seedlings carefully for a week before planting them in the garden, as they can be a bit tender.

What if my lettuce bolts?

Once a plant starts bolting, the leaves turn bitter. You can let it flower – the blooms attract beneficial insects – and then save the seeds for next year. Just pull the plant and replant with new seeds from your succession schedule.

Can I plant lettuce before the last frost?

Yes! Lettuce seeds can germinate in cool soil (as low as 40°F), and mature seedlings can tolerate a light frost. Use row covers if a hard freeze below 28°F is expected to protect young plants.

When is the absolute latest I can plant lettuce in fall?

You can push it by planting cold-hardy varieties 4-5 weeks before the first frost, especially if you plan to use season-extending covers like a cold frame. Growth will be slower, but you can often get a nice late harvest.

By following these guidelines for when to plant lettuce in Wisconsin, you’ll maximize your cool seasons and enjoy homegrown salads for much of the year. Paying attention to frost dates, using succession planting, and employing simple season extension tools makes all the difference. Grab your seeds, mark your calendar, and get ready for your best lettuce harvest yet.