How Coffee Grounds Can Upgrade Your Compost Pile

It's easy to assume that your coffee grounds no longer have a purpose once they've been deployed to make your morning cup of joe. But rather than tossing them in the trash (or putting coffee grounds down the garbage disposal, which you should never do), there are plenty of ways to reuse them that don't involve consuming them in any way. Making compost is already a sustainable way to return your leftover scraps to the soil, pumping the dirt full of nutrients from your discarded food. When you add your coffee grounds to the mix, not only are you avoiding wasting them, but you're actually enhancing the quality of your compost.

Not all leftover food provides quality material for your pile. For instance, you should never add meat to your compost. But previously brewed java can bring nitrogen to your composting efforts, which encourages everything to break down. In fact, it's often advised to add nitrogen fertilizers to your pile to help everything decompose properly. And while coffee alone isn't enough to do the job, it can provide a little boost. Plus, the caffeine in coffee grounds may repel garden pests like slugs and snails when mixed with water.

While adding coffee grounds to your compost pile comes with plenty of benefits (and prevents you from wasting your extra java), there are a few important things to keep in mind, here. If you're a daily coffee drinker, avoid dumping all of your leftover grounds into your dirt. Any good pile requires a balance of "browns" — elements packed with carbon or carbohydrates — and "greens," which are full of protein and nitrogen (like our coffee grounds). If you overwhelm your compost with too much nitrogen, it may heat up too rapidly, so aim for a 4:1 ratio of brown to green components. 

At the same time, don't count on your coffee to be your only nitrogen-infusing ingredient, since some of your soil's microorganisms will use it up. Instead, try incorporating items like fruit and veggie leftovers, eggshells, or a nitrogen fertilizer. But if you do want to sparingly pour your grounds on your compost, feel free to add them to piles in your garden as well as indoor composters. All you need to do is sprinkle them on top, then mix them in. And if you still have java to spare (we're looking at you, daily drinkers), we've rounded up nine more uses for your leftover coffee grounds, so you don't ever have to worry about wasting them.