Bobbi, It means either waster lots each day and make sure they have fertilizer or just pile more compost on top. I usually do a combo of the two. By next year, the soil underneath becomes nice and workable. The shallow debth is not ideal for tomatoes but I was too lazy to dig and do it the "correct" way. But you can just grow a tomato plant in a compost bag on its side with slits cut in and plant. No deeeper than what I have set up. So it can be done.
