Triad -- Some of us can't live without our coffee. That little morning jolt is necessary to start the day. There are some gardeners who feel like plants enjoy it just as much. Is there anything to that? Jeff Gillman got answers in his book, "The Truth About Garden Remedies".
In theory, according to Gillman, coffee grounds contain nitrogen. When it breaks down, it should add the element to the soil. Coffee is also acidic so it would make sense that adding the grounds to the soil would make it more acidic too.
Here's what actually happens. When the grounds are added to the soil, they begin to decompose... and the acidity is neutralized. That means increasing the soil's acidity isn't likely. If you want to add nitrogen to the soil, the best way to go is still fertilizer. While coffee grounds aren't necessarily bad for it, the soil doesn't really benefit either.
If you still have some discarded beans you're determined to use, there is a place for them. The compost pile does benefit from coffee grounds. In the compost pile, they are able to break down and release nitrogen. Plus, they raise and maintain a higher temperature. That can help kill pathogens in the pile.
Here's what you should never do. NEVER just pour coffee on your plants or in your compost pile. You're likely to end up with dead plants. Just enjoy that cup of coffee instead.
The Truth About Garden Remedies, Jeff Gillman