My grandma told me to put a rusty nail in my hydrangea pot and I thought she was nuts
She swore it would turn the flowers blue, something about the iron in the water. I was trying to get that perfect cottage garden look with big blue blooms, so I stuck an old nail from the shed in the dirt of my potted plant and forgot about it. Three months later, the blooms came in this weird, washed-out pink, not blue at all. Turns out, I have alkaline soil here, and the nail trick only works if your dirt is already acidic. I felt so silly for not just testing the soil first. Has anyone else tried this old trick and actually gotten it to work, or should I just give up and buy some soil acidifier?