Morning guys hope y'all having a blessed evening....
If I may chip in mr.Derby I'm not sure if by weathered you mean left open to Mother Nature or covered with tarp or plastic....haha
For my garden I dug knee deep holes bout 10-15gal, line the bottom 15cm with small rocks for drainage and fill half the hole with composted manure and bonemeal. Then rest of mix is compost/promix, kelp meal and amendments.
What would I change this coming summer make the mouths of the holes wider and half the depth of the centre hole ( hot tub seats style if you looking from above ) more area for roots to spread out for a firmer base as wind is a bugger. And if you have a bad back like me let her legs grow till waist high then lollipop for airflow and save yourself a whole lot of bending...haha