Are Coffee Grounds Good For Plants?

If you are anything like me, you go through a significant amount of coffee every week. And if you are brewing at home, that means you are generating a lot of waste. Every morning, I knock a heavy, wet puck of espresso grounds into my knock box, and for the longest time, I just dumped it straight into the trash.

But living in a condo filled with potted plants my wife and I started wondering if I was throwing away free fertilizer. We’ve all heard the old wives' tales, but I wanted to know the truth: are coffee grounds good for plants, or am I just going to kill my fiddle leaf fig?

The short answer is yes, but you have to be careful, especially with indoor plants.

The Benefits: Nitrogen and Nutrients

Coffee grounds are actually a fantastic source of nitrogen. In the gardening world, nitrogen is one of the key ingredients for green, leafy growth. They also contain potassium and phosphorus, making them a pretty well-rounded organic fertilizer.

If you have a compost pile, coffee grounds are considered "green" compost material (even though they look brown). Throwing your used grounds into the compost bin is hands-down the best way to use them. They heat up the pile and break down into rich, black earth.

Using Coffee Grounds on Indoor Plants

Since I live in a condo, I don't have a massive compost pile in the backyard. I have pots. Using coffee grounds directly on indoor plants requires a bit more caution.

1. Don't create a mold farm

The biggest mistake people make is dumping wet, soggy grounds directly onto the soil of a potted plant. Wet coffee grounds are a breeding ground for mold and fungus. If you layer them too thick, they form a crust that stops water and air from getting to the roots.

The Fix: Spread the grounds out on a baking sheet and let them dry completely before sprinkling a thin layer onto your soil. Or, mix them into the soil when you are repotting.

2. Watch the acidity

Coffee grounds are slightly acidic. This is great for acid-loving plants like African Violets, Ferns, or (if you have outdoor space) Azaleas and Hydrangeas. However, some plants prefer neutral soil, so don't treat every plant in your house to a coffee buffet without checking what they like first.

3. The "Coffee Tea" Method

Instead of putting the grounds on the soil, you can soak a cup of used grounds in a bucket of water overnight. Then strain out the grounds and use the liquid to water your plants. It’s a gentler way to deliver those nutrients without the risk of moldy clumps on your soil.

The Cycle of Good Coffee

It feels good to close the loop, turning a morning ritual into fuel for the greenery in your home. But of course, before you have coffee grounds, you need coffee beans.

I source all my coffee from Trade Coffee. They connect me with independent roasters across the country who care about sustainability just as much as quality. Whether you are drinking the coffee or feeding it to your plants, quality matters.

Disclosure: This post contains affiliate links. If you buy something through them, I may earn a small commission, at no extra cost to you. It helps fuel the coffee, the testing, and the writing. Thanks for supporting the work.