9 Ways to Use Coffee Grounds in the Garden

We love our morning cup of coffee! Did you know you can use the spent coffee grounds in your garden?

Espresso, latte, French press, drip, Keurig, hot or cold, it doesn’t matter as long as there is fresh coffee to drink.

How do you drink your coffee? Do you add half and half or sugar to yours? We do!

Making all that coffee leaves a ton of used coffee grounds. We used to throw them away. We thought, what else can you do with them?

Don’t toss them! We did some research and found that you can use coffee grounds in your yard and garden.

They can improve soil quality and encourage plant growth. They might even repel the pests that visit the garden too.

. . .

You’ll be surprised at how versatile coffee grounds can be.

Here are nine easy ways to use them in the garden.

1. Coffee Grounds as Slow-Release Fertilizer for the Plants

gloved hands adding a scoopful of fertilizer to a potted plant
Adding Fertilizer

Coffee grounds are high in nitrogen and contain some potassium and phosphorous.

All of these nutrients are important to plants.

You can use the coffee grounds as a slow-release fertilizer for the garden. Sprinkle the used coffee grounds thinly onto your soil and rake in.

You could make “tea” from the coffee grounds to add to the garden. To make it, add 2 cups of used coffee grounds to 5 gallons of water. Let the “tea” steep overnight.

Use it as a liquid fertilizer for garden and container plants. Also, you can spray the tea directly on the leaves of your plants as a foliar fertilizer.

2. Coffee Grounds as Compost Ingredient

making compost with green, brown and coffee grounds
Compost Mixture

Coffee grounds add nitrogen-rich organic material to the garden’s compost pile, which improves drainage, water retention, and aeration in the soil. You can add the coffee filters too!

Add the grounds to your compost pile. Using coffee grounds to make compost will lessen their acidity. In their raw state, coffee grounds may make the soil too acidic for plants to thrive.

The grounds should be relatively dry before using them, so they don’t clump together and interfere with the aerobic quality of your pile.

Green and Brown Material

Coffee grounds and filters are a green compost material.

Brown compost material includes dry leaves and newspapers. You want a 4-to-1 ratio of brown compost material to green compost material.

If you have too much of the green component, your compost pile will begin to smell. Not enough and the compost pile won’t heat up.

Mixing some lime into the coffee grounds before adding to the compost will result in a sweeter compost. Layer the ingredients using 3/5 leaves, 2/5 fresh grass clippings, and 1/5 coffee grounds/filters. Then spread the compost with the coffee grounds in it over the garden.

3. Feed the Worms with Coffee Grounds

Earthworms for Gardening
Feed the Worms!

Worms love coffee grounds. And gardens love worms.

Incorporate small quantities of coffee grounds to your worm bin every week or so. Don’t add too much at once because the acidity could bother your worms.

Another benefit of using coffee grounds in your garden soil is that they can attract earthworms to your garden.

And that is a good thing for the garden!

4. Add Acid to the Soil with Coffee Grounds

coffee as fertillizer
Using coffee grounds as fertilizer

Coffee grounds are said to be very acidic, but, in reality, they can vary from being acidic to slightly alkaline.

A pH of 6.5 is ideal for most gardens as plants grow well in the 6.0 to 7.0 range. However, each plant variety prefers a different level of acidity. You can find out what your plants like using this Soil pH Chart at Farmer’s Almanac.

It might be a good idea to have your soil tested for alkalinity/acidity levels, so you know what it’s missing. Or, you can try this method to determine your soil’s levels.

Used coffee grounds are closer to neutral, so they will probably not work to acidify higher pH soils.

Sprinkle fresh grounds (not used) around the roots of acid-loving plants like blueberries, roses, rhododendrons, holly, and gardenias.

NOTD: DO NOT USE AROUND TOMATO PLANTS! Keep coffee grounds out of the tomato area.

5. Mulch Around the Garden with Coffee Grounds

adding mulch around the garden beds with a rake
Mulch Around the Garden

Mulching around your garden plants can help control the weeds and keep their roots hydrated in hot weather. Coffee grounds offer variable particle sizes to the soil, which is an essential key to good soil structure.

First, you could incorporate coffee grounds by mixing them with other organic matter before using it as a mulch. Compost or leaf mold are both excellent items to consider.

Conversely, you can spread the coffee grounds around the garden and rake them into the top layer of soil, so they don’t clump together.

6. Improve Soil Hydration with Coffee Grounds

a person is spooning coffee grounds into potted plant
Coffee Grounds Aid Water Retention

Are the roots of your plants drying out even after you just watered your garden?

Coffee grounds can help improve the water holding capacity of the soil and help keep your garden plants hydrated.

Do this and no more drying out between watering sessions!

7. Control Weeds with Coffee Grounds

Weeds in the Garden
Pulling Weeds

Weeds are an ongoing battle for every gardener. Talk about four-letter words!

Spreading coffee grounds on top of the soil can create a barrier and help control the weeds in the garden.

You can spend your time on the fun aspects of gardening, like eating the harvests instead of pulling weeds.

Yum, nothing is better than freshly-picked vegetables!

8. Banish Garden Pests with Coffee Grounds

Slugs and Lettuce
Slugs Can Destroy a Garden

Slugs and snails don’t like coffee grounds. Building a barrier around your plants might keep the pests out!

Be sure to have a Plan B for pest control, however, as some researchers don’t think coffee grounds are effective against slugs, snails, or even ants.

9. Repel Cats with Coffee Grounds

Cat in the Garden
Unwanted Cat in the Garden

Cats dislike the smell of coffee. If you have a problem with the neighbor’s cat digging in your garden, put some coffee grounds in the soil to keep them out.

If you have a dog, don’t put too much out as the caffeine might be harmful to dogs.

. . .

Coffee grounds are free organic matter. They can be a worthwhile addition to your garden soil and compost pile if used with care and common sense.

And, if you’re not a coffee drinker, you can pick up free used coffee grounds at Starbucks or other coffee houses. Just ask, and they’ll probably be happy to give them to you.

We’re using coffee grounds in the garden here at Windy Gardens. Have you used coffee grounds in your gardening adventures? Leave a comment below and let us know about your experiences with using them.

Here are some other ways to improve your soil the easy way!

Happy gardening!

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