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  • Writer's pictureAnn Allanson

Why Use Coffee Grounds for Gardening

Updated: Apr 16, 2020

Plant shoot from coffee grounds

It's spring which means gardeners are itching to get their hands in the dirt! Well, for acid-loving plants, here's one ingredient that's a must, coffee grounds.

Coffee contains nitrogen, phosphorus, potassium, and trace minerals, as well as properties that help to stimulate the growth of beneficial microbes. When grounds are stored they tend to develop green or blue-green fungus that looks like mold.

The green fungus called Trichoderma, is very beneficial to the soil. The blue-green fungus is moderately beneficial. At any rate, moldy coffee is good to use directly in the garden, on your houseplants, or in the compost pile.

Take a look at some of the benefits.


Coffee Grounds as Pest Control ​​​

Aside from the slimy, icky factor of slugs and snails, these little creatures are quite destructive in the garden. To control them, scatter 2-5 pounds of coffee grounds per 100 square feet. They hate caffeine!

In fact, researchers discovered that a 1%-2% caffeine solution kills slugs and snails in two days. Concentrations as low as .01% repel these pests. (A cup of instant coffee contains .05% while brewed coffee contains more.)

Leftover Grounds for Composting

Using leftover grounds for composting is another way to add nitrogen to your soil, which helps produce healthy plants. And with coffee filters now biodegradable, you can toss the filters in with the rest of the heap!

Cheap, Eco-Friendly Fertilizer

Spring Flowers

Adding equal parts of topsoil and grounds will help to create a potting mixture indoor plants will love.

For flower beds, just sprinkle it straight on top, no thicker than a half an inch.

Otherwise, the grounds can fuse together creating a solid crust. This won't allow water to penetrate.

Use either a rake or a fork to spread the coffee evenly. Acid-loving plants like hydrangeas, tomatoes, and Lily of the Valley love this. If you're not sure about your plants, simply test it with a small amount on an individual plant.

What a cheap, eco-friendly way to love your soil and your plants to better health!


A big word that just means you invite earthworms to do the work for you. Not a bad deal for either of you! Earthworms love coffee bits and are instrumental in turning organic waste into extremely high-quality garden soil.

But why do they like them so much? Worms need gritty food to aid in their own digestion. That's why coffee grounds are perfect for them.

It's no wonder since worms are a gardener's best friend. They are a great way enrich the soil, keeping it full of nutrients.

Suppressing Fungal Disease

You may not know it, but coffee grounds are actually anti-microbial. When added to your garden soil, they can help stop fungal disease such as Pythium, Fusarium, and Sclerotinia.

Coffee Grounds

Studies show that as part of a compost, the grounds help to prevent these diseases from taking hold.

When you're ready to take a break from gardening, pop into the Coffee Cave. We'll fix you right up with a smoothie, your favorite cold brew or deluxe cup of coffee.

Visit us on the web!

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