I just dug the most kickass bed ever. It was this compacted red clay. It was so bad that when I was digging it, I actually found 5 or 6 bricks in it. But I couldn't even tell until it came out in a brick shape. I kept hitting hard stuff and thinking it was a brick but it was just clay.
Anyway, I took a pickaxe to it to break it all up, then carted off about 4 inches of soil. Added sphagnum moss, some sand and organic mulch. Turned it over a bunch of times. Now it is good draining dirt for about 8 inches. Technically, I would prefer a foot, but this is a tiny strip so I will only be planting small, shallow rooted plants.
I also "dug" the worst bed ever today. It is on a really sharp slope and was also totally compacted. If I loosened up the soil, it would just all slide down the hill. So I just graded it out a bit so the slope is not quite as bad. Then threw some organic mulch/ soil conditioner on top. Hopefully, the mulch will break into the soil a little bit. I dunno. The only thing that gives me hope is all my neighbors have the same soil and things grow on it. Granted, not much and not well, but it grows.
I have also thrown plants in there. Usually they die after a couple years because the ivy takes over, plus I ignore it. But the fact that it at least hangs on for a year or so gives me hope that with more attention and a lower grade to help hold water, it will work. At least for hosta.
Tomorrow, I dig the third tier in that hill. The soil there is loose because it is under my porch roof and never gets rained on. It is just kind of dust. So I will need to throw a lot of soil, moss, organic matter, etc. but at least it is easy to work with.