Coffee Grounds Hydrangea Color. Essentially, this means that you’ll want to make your soil more acidic. A cheap and easy way to change your hydrangea to blue is fertilizing the soil with used coffee grounds.

Thus, when coffee grounds are added to increase the acidity of the soil, it causes hydrangeas to change color. A cheap and easy way to change your hydrangea to blue is fertilizing the soil with used coffee grounds. Essentially, this means that you’ll want to make your soil more acidic.





