this must have been a high school project…
berries - do NOT wash in advance - that simply spreads any disease/spoilage to the whole batch, which goes bad before you can use them.
celery - aluminum is the most energy intensive packaging material - fyi for the carbonbigfoots. usually comes in a plastic sleeve - trim top to fit inside bag, give it a rinse with cold water to maintain humidity in the bag.
sealing greens inside an airtight container simply produces slimy leaves on a wet paper towel.