The next time you make a pot of coffee at home, you should think twice before dumping your spent coffee grounds in the trash.
Instead, you can put those grounds to good use in your compost pile or you can add them directly to the soil around acid-loving plants.
Why coffee grounds? They are highly acidic, which help lower the pH of your soil to create optimal conditions for certain plants that thrive in acidic soil. Plus, they are full of nutrients including nitrogen, potassium and magnesium which plants love.

Brian collecting coffee grounds in Canandaigua Store
How we use coffee grounds on our farm?
Every day we collect spent coffee grounds (filters and all) from our Canandaigua store for use on the organic farm.
We add them to our compost pile and keep a pile of them separately for use a few times in the spring and fall to apply directly to the soil around our blueberries, strawberries, raspberries and rhubarb (all acid-loving plants).

Coffee grounds around the base of a blueberry bush
When applied directly, we use about a shovel full of grounds per plant a few times in the spring and fall (which equates to about a month’s worth of coffee grounds for an average household).
Interested in putting your coffee grounds to use in your garden?
First, test the pH level of your soil to see if you need to increase the acidity. You can buy a test kit to check your soil pH or…you can simply check the pH levels using baking soda or vinegar: click here to learn how.
If you would like to complete a more comprehensive test of your soil (amount of nitrogen, etc.) you can drop a soil sample off at your local cooperative extension office. For a small fee, they will test it for you and give you a detailed report as well as recommendations for how to improve its quality. To find a soil testing lab in your area: click here.
Fast Facts about pH
- The pH of soil is measured on a scale of 0-14.
- A pH of 7.0 is considered neutral.
- The higher pH levels, the lower the acidity and vice versa.
- Soil is considered “alkaline” if it has a high pH (greater than 7.5) and “acidic” if it has a low pH (less than 6.5).
- For a list of plants that love acidic soil: click here
- For a list of alkaline-tolerant plants: click here
How to lower the pH/increase acidity: sprinkle some spent coffee grounds around the base of your plants. If you are worried about adding too much, simply add the coffee grounds to your compost pile to balance the acidity levels.
If you choose to add your grounds to a compost pile, allow for 6 months to a year for the compost to have the proper carbon/nitrogen ratio. As the coffee grounds decompose, nitrogen is released. Plus, the compost will act as a better soil builder than coffee grounds alone.
How to raise the pH/create alkaline soil: If you are growing plants suited for alkaline soil and need to raise the pH, try adding 1 tbsp of baking soda to 2 quarts of water around the plants.
I never knew coffee grounds could be so useful. I also heard that they are good for deterring slugs and ants.
If you have any suggestions on how to use spent coffee grounds in other ways, let me know!