If you drink coffee every day, those grounds add up to mountains. Instead of sending them to the landfill, try some of these creative uses for them.
Compost
Rich in nitrogen, and bacteria from it, your compost pile will love some coffee grounds to help it decompose all those organic elements. Besides that, the coffee grounds will help your compost pile not to be so stinky!
Fertilizer
That nitrogen in coffee grounds also make them a wonderful fertilizer, getting microbes to grow in the soil. It also is yummy food for your plants. Note: coffee grounds are not acidic; the acid gets released into the coffee when you make it—and drink it—making the grounds safe for garden applications.
Staining Wood
To make the stain, collect your leftover coffee grounds back into the pot. Add boiling water and let sit for at least two hours, though overnight is better. Then, filter out the grounds and put the liquid into a jar or other container that a paintbrush will fit in. To apply, let the brush soak in the fluid a while, then apply it generously to the wood surface. Continue to add applications until the stain is as dark as you like.
Mosquito Repellent
Mosquitoes do not like the strong smell of coffee, and research has found that it can kill their larvae. To use coffee grounds as a mosquito repellent, put some in small bodies of water near your house, such as puddles and small ponds. Some fin it effective to burn dry coffee grounds in tin cans or aluminum-foil-lined containers in the yard. You can also try mixing some coffee grounds with hot water in a spray bottle and spray infested areas.