Dear Dot: Can I compost coffee and tea?



Dot tackles your thorniest questions from a perch on her porch.

Dear Dot,

Someone told me that used coffee grounds are really good for my backyard compost. Is that true? Where can I get some?

–Tea Drinker, Tisbury

Dear Tea Drinker,

I am the proud owner of no less than four composters: three outdoors that I use in warmer weather for food scraps and yard waste, and an indoor vermicomposter (the Latin vermis = worm) that exists in my basement year-round devouring my food scraps, tea bags, and coffee grounds with an efficiency that would make the Swedish blush. Composting delights me, as does your question.

It feels like magic — you dump in your banana peels, your carrot peelings, your soggy, blackened lettuce that was part of your I-really-mean-it-this-time plan to eat more salads, and, yes please, your used coffee grounds — and it becomes nutrient-rich fertilizer for your plants.

Adding coffee grounds to your compost is particularly good on the Vineyard, because our soil is acidic, says Roxanne Kapitan, a 30-year composting veteran and manager of Oak Leaf Landscape in West Tisbury. “Good for growing blueberries,” she says. “Not so good for vegetables.” She explains that adding coffee grounds creates a pH of 6.5 to 6.8. “Almost all vegetable plants need that exact pH level.” Of course, I say, pretending to know what pH is.

Adding coffee grounds to your compost is particularly good on the Vineyard, because our soil is acidic.

Coffee grounds, which are considered “green” in compost parlance despite their actual color, neutralize or alkilize soil, and also accelerate decomposition. If your compost pile has just carbon (considered “brown,” and including twigs, leaves, even coffee filters, compostable coffee cups, or the newspaper you read with your coffee), it won’t heat up effectively. These are some magic beans: If your soil is sandy, coffee grinds will help it hold water. If your soil is more claylike, they will break it down so it doesn’t hold so much water. 

You might be able to convince your neighbors to save their coffee grounds for you. Mocha Mott’s takes its grounds to IGI, but also gives them out to composting customers, but please bring your own containers, and call or check in first so they can show you the ropes the first time. Espresso Love in Edgartown also offers up used grounds, but supply is first come, first served. And, again, check in first.

One more thing, Tea Drinker. As long as the tea bag itself is not made of synthetic materials, it can be composted. A blogger who goes by The Wild Minimalist has a comprehensive list of which popular US teas come in compostable tea bags. Or play it safe and open the bags, adding just the tea leaves to your compost.

Love, Dot

    Latest Stories

    What’s So Bad About … Carbon?

    Carbon is the chemical backbone of all life on Earth. But when we release too much...

    Building the M.V. Atlas of Life

    An Island biologist gets help from the community to fill in the blanks. A long morning walk...

    The No Nukes Festival: A day of music, friendship, and hope

    The No Nukes Festival was held on Martha’s Vineyard 45 years ago, and there are still...

    Farley Pedler Built a Small House, and Then He Built a Bigger One

    A builder takes a passive progressive approach to building for his family and his Island. Farley Pedler,...

    Laurie David and her 2021 Nissan Leaf

    For our second issue of Blue Dot Living I’m taking a cruise with environmental activist Laurie...

    Right at Home: Ben Robinson and Betsy Carnie at the Barnhouse

    A collage of creative, sustainable living.  It is a chilly June morning when I visit Ben Robinson...

    Citizen Science: A people-powered solution

    Not only can regular people do real science, the process could prove healing for individuals, communities,...
    Dear Dot
    Dear Dot is here to answer all your sustainable living questions from her perch on the porch. Got a question for Dot? Send her a note for a chance to be featured in an upcoming issue.

    Read More

    Related Articles


    Please enter your comment!
    Please enter your name here