Prepare your garden beds or containers with well-drained and nutrient-rich soil that is full of compost or aged manure. Lettuce plants do well in steady amounts of nitrogen, so apply blood meal or compost tea to the soil before planting.
Plant seeds ¼” to ½” deep in your favorite seed starting mix, or directly outside in your prepared beds. Start inside 4-6 weeks before your last frost date in spring, or 4 weeks early before planting out in fall. Try to situate your planting area where your plants will get 4-8 hours of sunlight a day. Heading-type lettuce will need sun closer to the 8 hours and leaf lettuces will do okay with at least 4 hours.
Thin your plants once the seedlings have formed their first real leaves. Thinning is simply removing certain seedlings to allow your plants to spread out. Leaf lettuce seedlings should be 4” apart while heads of lettuce should be 6 -8” apart. If you're growing organic lettuce heads, such as iceberg, aim for 12-14” apart. Single-leaf lettuce plants should be 4” apart.
Harvest your organic lettuce when the outer leaves are about 6” long. This ensures that the plant will survive after the leaves are removed. You can use your hands to tear off the leaves anywhere on the stalk once the leaves are long enough. Continue to harvest lettuce leaves until you are left with a center stalk. It may take as long as 80 days after planting to harvest. If you're harvesting heads of lettuce, cut the head 1” away from the soil. A new head should form in its place.