posted 9 months ago
Coffee grounds (used) are surprisingly in the low 6’s for pH in my testing and reading, with the acidity coming out in the brew. As are most conifer needles, with the acidity of conifer forest coming mostly from root exudates and fungal dominant soil processes. Still, again counter intuitively, I have seen creeks in old growth conifer forests run in the upper 7s for pH.
As mentioned above, I would suspect the compost being used is alkaline and bacterially dominant due to hyper-aerobic conditions from frequent turning. I would let it age at least a month, and if that did not suffice I would mix in up to an equal amount of wood chips and let it age unturned and with chimneys (Johnson Su/BEAM style) up to a year. It will then be in the slightly acidic range and extremely diverse, with fungal dominance. If this seems too time consuming, Iâd try intermediate amounts of woodchips or shredded leaves until you find your sweet spot.
This is all just my opinion based on a flawed memory