Lettuce like rich well drained soil that is not allowed to dry out. Dig plenty of manure or compost into the ground, rake the surface and finish with a general fertilizer. I prefer to sow lettuce in seed trays, that way I have optimum control over quantity and quality, the necessary thinning out is avoided and I stand a better chance against the onslaught of slugs in the early stages. Allow enough space between the lettuces, particularly the loose leaf varieties (mizuna can grow quite large) and keep watered.