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How to Use Coffee Grounds in Your Garden

Two Methods:Using Grounds as a Soil SupplementUsing Grounds for Alternate Tasks

Sick of throwing out cup after cup of grounds after your morning caffeine fixes? With their high nutrient content, coffee grounds can be used to make your garden thrive. They are naturally acidic and high in nutrients like nitrogen and potassium, making them a great choice for alkaline soils or nutrient-poor gardens. With a little creativity, coffee grounds can be used to help in a variety of other garden tasks as well.

Method 1
Using Grounds as a Soil Supplement

  1. Image titled Use Coffee Grounds in Your Garden Step 1
    Add coffee grounds to your compost. One of the simplest ways to use leftover grounds is to add them to the rest of your compost. In addition to providing extra organic matter, coffee grounds are able to speed up the decomposing process in compost. Getting this benefit is as easy as pouring the leftover grounds into the compost pile and mixing to incorporate them.
    • There are two main types of composting materials: "green" compost and "brown" compost. Coffee grounds are considered to be "green" compost along with other wet, nutrient rich materials. If you add a lot of coffee grounds to your compost, balance it out by adding some "brown" compost as well — dry, bulky materials like dry leaves, twigs, newspaper, straw, corn husks, sawdust, and so on.[1]
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    Add grounds to the soil directly to increase acidity. On their own, coffee grounds have a pH of about 5.1 — fairly acidic compared to the soil in most gardens. Though this can be too acidic for some plants, it's perfect for some that require extra-high acidity. Just sprinkle a handful of grounds near the roots of the plants at the start of the growing season to get the acidifying effect. Blueberries, cranberries, and citrus fruits like coffee added to their soil. Other coffee-loving plants include camellias, gardenias, rhododendrons, and vireyas.[2]
    • Some flowering plants will give different-colored blooms in acidic soil. For example, the addition of coffee grounds to hydrangeas is good for blue blooms.
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    Consider adding lime to balance coffee's pH. As noted above, coffee grounds' natural acidity can make them inappropriate for many "average" gardens. To mitigate this, mix a pinch of lime with the grounds. Lime is naturally alkaline (or "basic," the opposite of acidic) and will work against the acidity in the coffee grounds. This lets you add coffee grounds directly to your garden as a mulch or soil conditioner.
    • Lime (often sold as "garden lime" or "agricultural lime") is a powdery substance that's not related to the green citrus fruit of the same name. You can usually find it at hardware stores or gardening supply stores for fairly cheap.
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    Use coffee grounds to add nutrients to your soil. Acidity isn't the only thing that coffee ground have to offer. They are rich in several nutrients that are critical to healthy plants, so if your garden lacks these, coffee grounds are an excellent choice. See below:[3]
    • Coffee grounds are rich in:
    • Nitrogen
    • Magnesium
    • Potassium
    • Coffee grounds are not rich in:
    • Phosphorous
    • Calcium
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    Optionally, make a liquid plant food. You don't need to use the coffee grounds themselves in your garden — you can also make a nutritious plant food from them and use it instead. To do this, place a handful of coffee grounds into a bucket of water. Let it sit in a cool, out-of-the-way place (like your garage) for a day or two. It should create a nice amber-colored liquid. Strain the remaining grounds out, then use the liquid to water your plants.
    • It will have the same acidity and nutrient content as normal coffee grounds, so use it with caution if your plants don't require high acidity or nitrogen, potassium, etc.

Method 2
Using Grounds for Alternate Tasks

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    Use grounds to deter pests. Slugs and snails can chew up your most prized plants, but they are not fond of coffee grounds. Sprinkle a handful of grounds around the bases of plants you want to protect. If you're worried about increasing the acidity of the soil, make a solid ring of grounds farther away from the base.
    • It's thought that this works because the caffeine in the coffee grounds hurts these pests.[4]
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    Use grounds to keep cats out of your garden. Coffee grounds aren't just good for tiny pests. They can also be used to keep feline friends from playing in your delicate plants. In this case, use the grounds just as you'd use them to repel snails — sprinkle them around the plants you want to protect. The acidifying effect on the soil may be unavoidable here due to how much you'll need to use.
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    Use coffee grounds as worm food. If you participate in vermiculture (raising worms), you have a great opportunity to use up your coffee grounds. Worms love to eat coffee grounds, so feel free to add plenty to your worm bin or a worm-containing compost pile. Note, however, that coffee grounds should be part of a balanced diet: fruit and vegetable scraps, newspaper, leaves, and so on should accompany any coffee grounds you add.[5]
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    Use grounds to discourage fungal infection. There is some evidence that coffee grounds can be used to prevent certain types of fungus from attacking your plants. A light sprinkling of coffee grounds may be able to prevent Fusarium, Pythium, and Sclerotinia species of fungi from taking root. Tomatoes, eggplants, and peppers are especially vulnerable to fungal infections, so coffee grounds make an especially good choice for these plants.[6]


  • Unsure what your garden's pH level is? See our article on testing soil pH.
  • For a steady supply of free grounds, start a sharing relationship with your local cafe. Many cafes will give away their used coffee grounds for free and in convenient packages. If they're not already doing so, ask if they will keep some aside for you. Often, the grounds are simply treated as waste, so many cafes will be happy to give them away.

Article Info

Categories: Compost Mulch and Soil Preparation