The potting soil that I use is peat based with a pH of 6, so a little more acidic. Our soil & tap water in Calgary is very alkaline 7.5 to 8 pH. I do amend the soil with compost etc, otherwise it would be hard as a rock. I think the Epsom Salts make a huge difference for my garden, containers and in-ground planting.
I also add Epsom Salts around my tomatoes & peppers.
