the brown cubic rot looks like some interesting stuff to learn
thats about the only way that wood rots around here when above ground(i have no idea what it does below ground yet)
EDIT: AWESOME OP on hugel-containers btw
the only container
gardening im really doing is for my potatoes, with big buckets, so i never changed out the soil last 2 years now
last spring i mixed peat moss and compost as well as some
native soil, i planted 3 potatoes per
bucket and mulched with
straw
with each layer i just piled soil on top of the last layer of straw mulch
at the end of the year i harvested my potatoes(better than plain soil but not near as good as expected) and then mixed the straw and soil together and left it over the winter
now this spring i went to check the pots when i came back to the land.... BLACK, RICH, AMAZING SOIL!
so i then removed excess soil, planted potatoes low again, and mulched with wood chips this time
now on the second of 3rd layer, i pulled mulch aside this time with next layer of soil and replaced it onto the top, this time, when i pulled the mulch back for the new layer, there was a spud growing right on the surface of the ground, under the mulch!
i pulled this spud and cut it in half and planted it in the
hugelkultur bed, no plants coming up just yet from that but thats ok so far
i think as the years go on this is going to become better and better pots for potatoes, and i would bet harvest this year will be much bigger than last years.