The patch in the photo, and the plants in the garden are in leaf mulch only, but both have been setting for a several years, so it's broken down and composted, and it really softened up the earth below it, and I've added new mulch each year to them as well.

The photo of the plant in bloom is actually in straw and burro manure that I piled up in late Summer and let sit until early Spring for two years in a row now. Last year the earth under it was still a bit hard, but this year it was soft and there were a lot of worms working it. I'm hoping it will produce better this year than last, but I haven't done any checking to see what's under it yet.

In my garden, I actually dug and loosened the soil about 6 inches deep beneath the mulch and buried my seed potato about 3 inches deep. I really didn't even expect them to sprout at all with a foot of mulch on top of that, but most all the plantings did. What I don't know is where I'll find the potatoes. I've never buried them like that before, so I'm not sure it the new potatoes will grow on top of the dirt and just under the mulch like they do in the other patches, or if they'll actually grow under the surface of the dirt.

When I first dug the trenches to make my raised beds I dug all the decent top soil up. There was only about 12 inches of hard dirt, so that's how deep the trenches were before I started filling them with leaf mulch. Under that dirt was rock hard clay and and rock and grit. It was as poor as any soil I've seen anywhere.

As I've said, I've filled the trenches every year since for about 4 years now. When I planted those potatoes this year I dug through the mulch down to the dirt which is now soft and black and rich, and full of worms, and is about 6-8 inches deep before it hits that hard clay again. It's still got a lot of rocks in it, but it's good dirt. The worms came when I put the mulch there and they've done an amazing job of enriching that soil. I figure in another year or two I'll take some of the dirt out of the trenches and make another row of raised bed with it.