I must've had it backwards. I knew ashes affected the soil one way. M-Gro was used as it became a garden. It wasnt really planned. I just started turning over the dort one day and wham. Plant after plant was slowly brought in. I really prefer adding organic amendments. Thats what my cannabis grows in. M-Gro was good for fruit production as it rocked. Yet as you mention what about by products and leaching in to the soil. Next year maybe different. I prefer heavily amended soil so i dont need to tend to it as much. Maybe a top dress after a bit.