An exposé on using biochar as an additive for trees, shrubs, and other plants. Using this article, and trialling pots at home, I have settled on this as a viable technique for raised garden beds. You can check out some growth on the Mastodon link.
https://elk.aus.social/aus.social/@treevan/110293053188000541
A simplified recipe as below.
I don’t recognise them but here in Australia, we have our own edible Araucaria, A.bidwillii - Bunya Pine. If one is young enough, should see some nuts in 20 years or so (before phytophthora kills them - a new disease destroying Bunya Pines in our location).