If you make a daily pot of coffee, you have a fabulous source of organic matter right at your fingertips. In compost jargon, coffee grounds are a "green," meaning an item that is rich in nitrogen (yes, I know coffee grounds are brown. In your compost, they're green. Trust me.) Coffee grounds are approximately 1.45% nitrogen. They also contain magnesium, calcium, potassium, and other trace minerals.
There are several ways you can put used coffee grounds to work in your garden:
- Put coffee grounds in your compost bin. As noted above, they are a valuable source of nitrogen.
- Add grounds directly to the soil in your garden. You can scratch it into the top couple inches of soil, or just sprinkle the grounds on top and leave it alone.
- Create a slug and snail barrier. Coffee grounds are both abrasive and acidic, so a barrier of grounds placed near slug-prone plants may just save them from these garden pests.
- Make coffee ground "tea." Add two cups of used coffee grounds to a five-gallon bucket of water. Let the "tea" steep for a few hours or overnight. You can use this concoction as a liquid fertilizer for garden and container plants. It also makes a great foliar feed.
- Add coffee grounds to your worm bin. Worms love coffee grounds! Add some to your worm bin every week or so. Just don't add too many at once, because the acidity could bother your worms. A cup or so of grounds per week for a small worm bin is perfect.