Lettuce prefers cooler weather and will bolt (flower) earlier in hot weather. For early head lettuce, start seeds indoors 3/1 at 68° (cover flat with a dome and expose seeds to light). Sow lettuce seeds outside anytime between 3/27 – 6/30. Lettuce seeds germinate when the soil temperature ranges from 35-80° (68° optimum). Lettuce seeds need light to germinate - plant seeds on the surface of the soil and pat gently with a hand. Keep seeds constantly moist until germination (laying row cover fabric on top of the seeds will help keep them cool and moist). Days to germination: 2-14 days. Space 8” apart for head lettuce.
Harvest the lettuce head with a knife as it forms a full size loose head but before it begins to bolt.
Lettuce is mostly self-pollinated and rarely crosses with other lettuces. Isolation distance: 12’. Minimum population size: 5-10 plants. Remove early bolting plants. If lettuce stems fall over, stake them. Harvest lettuce seeds as they begin to mature (they will form dandelion like white plumes on them). Harvest seeds by tapping stems to shake seeds into a bucket. It is best to harvest lettuce seed after several days of dry weather. Harvest seeds over several weeks.