What is the best way to turn soil from alkaline to acid?
I recently planted a pink Hydrangea. I know that it is pink in alkaline soil and blue in acid soil. What is the best, and safest, way to turn it to acid soil?
A lot depends on the water you use, if you irrigate. Get your soil and water pH tested, and go from there. Some local plant stores will have the kits if you don't have a pH tester. They will also tell you what and how much chemical to use to get what you desire.
What is the best, and safest, way to turn it to acid soil?
I do not know if it is the best, but one way to acidify soil is adding coffee grounds. Check your local coffee houses as many of them have starting bagging the coffee grounds to take home and put in your garden. Starbucks does this. More info here:
https://www.gardeningknowhow.com/composting/ingredients/coffee-grounds-gardening.htm