When to Plant Lettuce in Missouri (2026 Guide)
Growing lettuce in Missouri can be a delightful experience for gardeners of all skill levels. Knowing the right planting times is crucial, as the median last spring frost varies by region. In Zone 6b, which includes cities like Arnold and Ballwin, the last spring frost occurs around April 10, while in Zone 6a, it is approximately April 19.
Lettuce thrives in the cool weather of early spring and late fall. To take advantage of Missouri's climate, timing your planting is key. With a frost-free season of about 195 days in Zone 6b, you can start sowing seeds indoors as early as late winter, while in Zone 6a, your indoor sowing can begin in early spring.
To ensure a continual harvest, consider using succession planting, which allows for a fresh supply of lettuce throughout the growing seasons. The first fall frost in Missouri typically falls around October 22 in Zone 6b and October 12 in Zone 6a, signaling the time to prepare for your final harvest.
Planting Schedule by USDA Zone in Missouri
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 6b | Start February 15 – March 1, ~6–8 weeks before April 10 | Transplant outdoors between April 10 – April 20, after the last frost | Direct sow seeds from April 10 – June 15, and again from August 1 – September 10 | Harvest from May 15 – June 30 for spring crops, and from September 15 – October 15 for fall crops |
| Zone 6a | Start March 1 – March 15, ~6–8 weeks before April 19 | Transplant outdoors between April 19 – April 30, after the last frost | Direct sow seeds from April 19 – June 5, and again from August 1 – September 5 | Harvest from June 1 – July 15 for spring crops, and from September 1 – October 5 for fall crops |
Lettuce Planting Windows in Missouri
- Indoor start: In Missouri, start your lettuce seeds indoors between February 15 and March 1, depending on your zone.
- Transplant outdoors: Transplant your lettuce seedlings outdoors from April 10 to April 30, based on the zone you are in.
- Harvest: You can expect to harvest lettuce from around May 15 to June 30 for your spring crops and again from September 1 to October 15 for your fall crops.
Common Mistakes Growing Lettuce in Missouri
- Many new gardeners in Missouri underestimate how quickly soil temperature can rise, leading to premature bolting of lettuce. Planting in mid-to-late summer temperatures without shade can result in disappointment as lettuce begins to bolt early.
- Failing to succession plant is another common mistake in Missouri. By not sowing seeds every 2–3 weeks, gardeners risk an overwhelming harvest all at once or prolonged gaps without fresh greens, especially in the unpredictable Missouri climate.
- Some Missouri gardeners mistakenly cover lettuce seeds too deeply when planting. Lettuce seeds require light for germination, so be sure to press them into the soil surface and avoid burying them too deep, which can hinder germination.
- Missouri's transitional climate can lead to unexpected late frosts. Be prepared to protect your young lettuce plants with cloches or row covers if temperatures drop unexpectedly after the median last frost date.
- A common error is not accounting for humidity levels in Missouri, which can impact lettuce growth. High humidity can promote fungal diseases, so ensure good air circulation around your plants and consider spacing appropriately.
Frequently Asked Questions
What if I'm in a cold pocket of Missouri?
If you're in a cooler region, consider starting your seeds indoors even earlier. You can extend your growing season by using cloches or row covers to protect delicate seedlings from sudden temperature drops.
Can I still plant lettuce in May?
While May is generally warm, you can still plant heat-resistant varieties of lettuce in early May, especially in shaded areas. Just be mindful of bolting as temperatures warm up.
How can I extend my lettuce harvest in Missouri?
Succession planting every 2–3 weeks helps provide fresh lettuce throughout the spring and fall. Additionally, plant in shaded areas to reduce stress during the hotter summer months for better yield.
What are common diseases I should watch for?
Watch for common fungal issues like downy mildew, which thrive in Missouri's summers. Ensuring good airflow and proper spacing can help mitigate these problems.
When is the best time to harvest my lettuce?
The best time to harvest your lettuce is in the morning when temperatures are cooler and moisture levels are higher, ensuring crispness. Regular harvesting encourages ongoing growth and prevents bolting.
Keep Learning
City guides in Missouri
Other crops in Missouri
Typical fall sowing window for Lettuce in Missouri: August 7 – August 28.