Compost Your Coffee Grounds

Coffee Grounds Make a Great Ingredient for Your Compost Pile Photo: Marco Verch
Next time you order a latte at your favorite coffee shop, ask if they save the grounds from all the coffee they brew.

When I go to my local coffee shop, I often come out with more than a cup of coffee. Near the door, they have a bin with free bags of used coffee grounds. Like most avid gardeners, I find it impossible to resist free food for my garden!

In the spring, I spread handfuls of coffee grounds around my acid-loving plants—azaleas, blueberries, rhododendrons. The grounds are slightly acidic and besides helping to lower the soil pH, they foster the humus-rich soil texture these plants really love.

In late summer and fall, I dig coffee grounds right into the vegetable garden after removing early-season crops such as peas and spinach. In the winter, I add the grounds to my compost pile. They’re a good source of nitrogen at a time of year when that can be a little difficult to come by.

Browns & Greens

Efficient composting depends upon a well-balanced mix of ingredients, which generally fall into two categories: browns (high carbon), and greens (high nitrogen). The list at right gives examples of both types of ingredients. The ideal ratio is 25:1 (brown to green) but most people find three parts brown and one part green works quite well. Remember to layer your ingredients, keep the pile moist (like a well-wrung sponge) and turn it occasionally to incorporate a fresh supply of oxygen for the microbes.

Browns (3 parts) Greens (1 part)
corncobs and cornstalks paper pine needles dry leaves sawdust wood shavings straw woody vegetable stalks coir coffee grounds eggshells fruit trimmings vegetable peels and leaves grass clippings feathers or hair green leaves seaweed fresh weeds rotted manure alfalfa meal

Last updated: 01/27/2021