In general, most of the acidity is removed from the grounds during the brewing process, the grounds have an average pH of 6.9 and a C-N ratio of 20:1. They are particularly great for mulching acid-loving plants like rhododendrons and azaleas. They also function as an excellent accelerator for compost to increase nitrogen balance. Consider coffee grounds “green” material, similar to grass clippings. Microbes will turn the coffee from slightly acidic to a neutral level, so they will not turn the compost pile acidic. Coffee grounds should be limited to 25% of the volume of your compost pile.
Coffee Grounds are one of the best-kept garden secrets, and offer the following benefits:
- They smell great
- Good source of N
- Coffee grounds used as mulch will help reduce slugs and snails
- Great food for worms and worm farms
- Available in large quantities for free from Starbucks – Thanks!!