Ideas for Recycling Spent Coffee Grounds

I once read an article where scientists at the University of Nevada, Reno, were able to extract the leftover oils from spent coffee grounds from local coffee shops and convert the oil into biodiesel to fuel cars. I thought that was awesome, using something that would have otherwise been trashed and (literally) squeezing one more use out of it. As I questioned if spent coffee grounds could realistically power my car one day, I wondered how many people knew that they could reuse spent coffee grounds and recycle them today in a number of ways.

The hack

Before you throw out your spent grounds, check out the following uses.

Fertilizer – Spent coffee grounds make a great organic fertilizer for your lawn or garden. Set the wet grounds aside for at least a day or two. After they dry up you can start spreading over whatever needs fertilizing. Don’t apply too much on any particular spot, though. The nitrogen will release quickly so make sure to just use about 5-6 tablespoons per plant. After spreading the grounds, apply a little water to speed up the absorption. Coffee grounds do not have phosphorus (commonly used in fertilizers) so I don’t recommend using them on plants that flower, but the grounds work very well on shrubs, plants and grass.

Insect repellent – For whatever reason, insects really don’t like coffee. It’s a natural repellent. You probably don’t want to line the inside of your house with coffee grounds, but you may want to try sprinkling some spent grounds on ant hills and around the perimeter of your house, at least by your doors, a barrier of sorts to keep the bugs away.

Fridge deodorizer – Remember earlier when I suggested that you don’t try to keep your coffee fresh by storing it in the refrigerator unless you wanted your coffee tasting like leftover pizza and asparagus (because coffee is porous and tends to absorb the tastes and smells of the things around it)? Well, that’s exactly the same reason why you should store spent coffee grounds in the fridge, to absorb the different odors inside. Try refilling the Arm and Hammer box with spent grounds the next time it needs changing.