I would recommend following use case #2 in the following post, up to the point where you get a sequentially number index number starting at 0 and counting up as you add rows.
Once you have that index number column, add a basic date column to accept a date and populate it with a date in the first row. Then add a single value column to populate that date on all rows. Finally add a math column with a formula to add the row index number to the date. That should be it.