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How to grow iceberg lettuce
Plant the iceberg lettuce six to eight weeks before the last expected spring frost.
Fill the bottom of each cell of the tray with some standard potting soil before you sprinkle a few seeds into each cell. Cover the seeds with with a light layer of potting soil.
Plant iceberg lettuce seeds in a shallow seed tray. Check the seed tray every day, and water the seeds whenever the soil feels dry.