The Truth About Coffee Grounds

For years, gardeners have been told to dump their morning coffee grounds straight into their flower beds. But is this actually helpful, or could it be harming your plants?

The Acidity Question

The biggest myth is that coffee grounds will make your soil highly acidic, perfect for blueberries and azaleas. In reality, most of the acid in coffee is water-soluble, meaning it ends up in your cup, not the grounds. The used grounds are only slightly acidic, hovering around a pH of 6.5.

The Nitrogen Factor

Coffee grounds are rich in nitrogen, a vital nutrient. However, it is not immediately available to plants. The grounds must decompose first. If you add too many uncomposted grounds directly to the soil, they can actually tie up nitrogen as they break down, temporarily starving your plants.

The Best Way to Use Them

The ideal way to use coffee grounds is to add them to your compost bin! They are considered "green" matter and will heat up your compost pile beautifully when mixed with "brown" matter like dried leaves or cardboard.