Well I got back to the deck box yesterday afternnoon.
It's been awkward digging under the bottom of the deck. But I had a great idea. I stood on the sunken patio and dug at waist level into the framed soil. It went GREAT! Very little lifting and easy tossing to the low side. I was able to move the poor existing soil evenly throughout the framed bed.
That left 4" of better soil to add. Well, I have soil in the old garden area I need to move in order to build new framed beds. So there was some digging and wheelbarrow transfer involved for several trips. I filled the deck bed about halfway to filled with garden soil, and raked it smooth.
Since it is going to be a hosta bed (and they don't love REALLY rich soil), I'm going to solve two problems at once!
Remember from yesterday when I mentioned the lawn was too high for the sunken patio to drain well? Well, I'm going to fill up the rest of the deck bed with soil above the edge of the patio. They are right in the same place. There is no grass there at the patio edge (too much foot traffic and water), so it can go right in. Hurray!
I LOVE solving two problems with one action!