Lettuce - Salad Bowl This variety crops all summer long, and is slow to run to seed. Pick individual leaves as needed or whole 'non-hearting' heads. Sow outdoors thinly, from March to August where they are to crop, 1.5cm deep, directly into finely-prepared, fertile, moisture-retentive soil, which has already been watered. Allow 25cm between rows. Early sowings may benefit from cloche protection. Seedlings usually appear in 7-14 days. Thin out to 20cm apart. No thinning is necessary if only baby leaves are required. Water well until plants are established. Regular sowings, made every two to three weeks, will ensure a continuous supply. Harvest from April to October.