How to Start Lettuce Seeds
Fast-growing, easy lettuce can give you fresh salads within weeks
Lettuce Likes It Cool!
Unlike most vegetables, lettuce prefers cooler temperatures (60-68°F) for germination. Hot weather causes thermodormancy - seeds simply won't sprout above 75°F.
Step-by-Step Guide
Prepare Containers
Fill cells or flats with moistened seed starting mix. Lettuce can be started in cell trays or direct-sown in larger containers.
Surface Sow Seeds
Sprinkle seeds on surface and press lightly. Cover with 1/8" soil or vermiculite at most - seeds need light! Mist gently.
Keep Cool & Moist
Ideal germination: 60-68°F. Avoid heat mats! Keep soil consistently moist with misting. Seeds should sprout in 2-7 days.
Provide Light
Give seedlings 12-16 hours of light daily. Lettuce tolerates partial shade, but more light = faster growth.
Thin or Transplant
Thin to proper spacing or transplant when seedlings have 3-4 true leaves. Lettuce handles transplanting well at any size.
Succession Planting for Continuous Harvest
For salads all season, sow new lettuce seeds every 2-3 weeks:
Spring
Start 4-6 weeks before last frost. Lettuce handles light frost.
Summer
Choose heat-tolerant varieties. Sow in evening, keep cool.
Fall
Best lettuce season! Start 6-8 weeks before first frost.
Frequently Asked Questions
How long does it take lettuce seeds to germinate?
Lettuce seeds germinate quickly - usually 2-7 days in optimal conditions (60-68°F). Warmer temps can actually inhibit germination, a condition called thermodormancy.
Should I start lettuce indoors or direct sow?
Either works! Start indoors 4 weeks before transplanting for a head start, or direct sow every 2 weeks for continuous harvest. Lettuce transplants easily at any size.
Why won't my lettuce seeds germinate in summer?
Lettuce has thermodormancy - seeds go dormant above 75°F. For summer sowing, pre-chill seeds in refrigerator for 3-5 days, then sow in evening when soil is cooler.
Do lettuce seeds need light to germinate?
Yes! Lettuce seeds need light for best germination. Press seeds onto soil surface and cover very lightly (1/8 inch at most). Don't bury them deeply.