Finally getting around to putting in my submission for the first 6 ft section completed of hugel bed at the specifications for this bb. It is intended to be a good deal larger at some point but other tasks have my attention for now. This was a slow hand-build process aimed at achieving long lasting fertility. My techniques evolved as I went. You can see my more detailed series of posts on the ongoing project with lots more photos here:
https://permies.com/t/269642/Hand-built-hugelkultur-frog-pond#2830247
Most of the soil came from digging a pond on the site and thoroughly mixing that mostly subsoil with ground charcoal and compost from onsite. I live in Atlanta, city in a forest, so plenty of wood around our properties and the neighbors. We deal with a lot of aging trees coming down or dropping limbs, especially the massive water oaks (Q. nigra) which grow very fast but are relatively short lived. A large pecan had come down a couple years earlier and a lot of that went in too. Beyond that there was beech, boxelder, privet, black cherry, american elm, mimosa (Albizia), a little pine, and probably more species that I have forgotten.
Aside from the required comfrey, sunchokes, and Sepp grains I also transplanted tomatoes, milkweed, elecampane, trailing nasturtiums and kale. I seeded with iron and clay cowpeas, bush beans, illinois bundleflower, vetch, and burr clover for nitrogen fixers as well as beets, carrots, salsify, vegetable mallow, papalo, other greens and a packet of mixed edible flower seeds.
The mound was somewhat mulched as it was built as I used weedy plants (lots of cleavers) to hold the soil in place as it ascended. I used lots of old plant stalks of things like goldenrod in a penetrating manner as I did the secondary covering of the steep sides. A little bit of full on wattle construction was helpful at holding it up here and there too. Additional mulches came in the form of old tomato vines and such from spring garden cleaning, fast growing green weeds like lactuca and pokeweed, as well as the material from cleaning off the nearby woodshed roof and gutters. I also coppiced some nitrogen fixing Albizzia and stripped it of leaves and twigs and bark for mulching with.
This took quite a while working on it intermittently and I found it a challenge at times. I would prefer to construct them a good bit wider for that height but the space was too tight for that. Hopefully I'll get back to completing the next 12 feet before too long.