Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to grow iceberg lettuce [title] Plant the iceberg lettuce six to eight weeks before the last expected spring frost. [step] 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.

Ending1: [title] Plant iceberg lettuce seeds in a shallow seed tray. [step] Check the seed tray every day, and water the seeds whenever the soil feels dry. Ending2: Pat down with your hands the soil to keep it moist. [title] Grow each iceberg lettuce seedling without additional potting soil. Ending3: [substeps] The trays should be placed in a well-ventilated area, and only ever open to 24 hours of sunlight. Iceberg lettuce seeds should be transplanted before the frost, so that the temperatures do not rise too much. Ending4: [substeps] You can do this in the spring or after the frost. [title] Water after there's still water.

Answer format: ending1/ending2/ending3/ending4