Basil Lettuce Leaf Seeds produce large, tender, crinkled leaves perfect for salads, sandwiches, and wraps. These mild, sweet basil leaves are a great alternative to lettuce and hold dressings well. Sow seeds directly in well-drained, fertile soil after late spring when temperatures warm, spacing them 1 inch apart. Cover with 1/4 inch of soil and keep moist; germination takes 1 to 2 weeks. Thin or transplant seedlings to 8 inches apart once established. For an early start, sow indoors 4 to 6 weeks before the last frost, ensuring warmth and good light. Pinch off growing tips to encourage branching, and regularly harvest leaves for continuous regrowth.