How To Grow Lettuce

Planting Lettuce

Lettuce can be started indoors or directly sown into rich, well-draining soil. We recommend sowing directly outdoors 2 weeks prior to last frost. For this method, broadcast seed lightly in soil that is under 75° (except for heat tolerant varieties) and barely cover with dirt. When plants have sprouted, thin leaf lettuce to 4-8 in. apart and head lettuce 6-12 in apart. Soil pH should range from 6 to 7.5. For starting indoors, sow seeds 2-6 weeks before last frost. When preparing transplants, harden off for one week before planting them outside. Germination should range from 6 to 10 days.

Harvesting Lettuce

Lettuce has been found to last longest and taste best when harvested in the cool of the morning and transferred directly to a cool environment. If you wish to prolong the harvest season of your lettuce, picking individual leaves is recommended. Harvesting the whole plant is also an option, as long as you cut the plant off above the growing tip. Baby lettuce is harvested when the leaves are young and tender. For adult lettuce it is important to harvest before the leaves get tough and the plant bolts, because there is a strong tendency for the leaves to get bitter after that point. Head lettuce should be harvested when the head is firm and solid. Outside leaves may turn slightly yellowish green, but inside leaves are still good and useable.

Saving Lettuce Seeds

After plants have bolted and eventually bloomed, carefully shake the seed head into a paper sack and allow the mature seeds to fall into the sack while the immature seeds will stay on the plant to be harvested at a later date. Gather every few days until there are no more seeds remaining to be harvested. Seed viability can range anywhere from 2 to 6 years under cool and dry conditions.

Common Problems

  • Downy Mildew
    Signs include pale green areas on the top of leaves changing to yellow, white/gray color on lower leaves, and leaf edges curling inward. Treat with neem oil, making sure crop has good air circulation, full sun, low humidity and crop rotation.

  • White Mold, Damping Off, and Bottom Rot
    These three common problems are best prevented by maximizing air flow around plants and keeping dry.

Suggested Companions

  • Onions
  • Strawberries
  • Cucumbers
  • Carrots
  • Radishes
  • Tomatoes
  • Bush Beans
  • Pole Beans