April 5, 2014


Mushrooms grown on green waste

Spent coffee grounds and pulp can be re–used to grow mushrooms that have great health benefits

By Daniel Hills

Coffee is grown under stringent conditions. From growing beans, to roasting and brewing, almost every step in the processes of taking a bean from the farm to getting it into your mug is monitored closely to maximize flavor and uniformity of taste. Coffee is also one of the most wasteful crops, only about .02% of the coffee is ingested. The byproducts created to brew your favorite cup of joe don’t have to waste away in a landfill where they contribute to the creation of greenhouse gases. Waste from the coffee making process can be used as compost fertilizer, or most productively as the foundation for growing mushrooms.

In the coffee making process most of the waste comes from the pulp and the grounds. The pulp is the outer area of the coffee bean; this is shed before the bean leaves the farm. The second source of coffee waste is what is leftover after brewing has taken place those are the spent grounds. These two sources of coffee waste are known as lignocellulose, a naturally occurring biomass present in plants, which happen to be exactly what mushrooms grow best on.

There are multiple ways to employ spent coffee grounds for growing mushrooms– you can also use coffee bean pulp if you live near a coffee farm. Basically you just need to mix mushroom spawn and coffee grounds, keeping the mixture damp, and mushrooms will grow on their own. You can buy mushroom spawn online and follow this how to guide, you can also buy pre mixed kits, then all you have to do is cut the bag open and watch you mushrooms grow, but you won’t be using any coffee grounds of your own.

Mushrooms are a great source of potassium and the presence of linoleic acid, an unsaturated omega–6 fatty acid, means they help also prevent breast cancer, eczema, and osteoporosis, among other health benefits. Anyway to repurpose or use household waste to keep it out of the landfill is great, be creative and come up with unique ways to minimize our carbon footprint.

Have a cool way of re–using organic waste? We want to hear them! Email editor[at]theoptimist[dot]com with your re– sourceful ideas.


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  1. Frances Griffiths

    I have just put my coffeegrounds in the compost for 20 years….along with the filter paper. It all disappears eventually, & the earth looks rich.

  2. Coffee grounds are a great soil conditioner, especially for acid-loving plants, such as Azaleas, Camellias, Rhododendrons, ferns, etc. When planting, mix them into backfill; for established plants, scratch into soil surface, then water in.

  3. Amanda Petrona

    You mention organic waste. Coffee beans are not always organic and are usually sprayed with pesticides. (Although I imagine your readers would be using organic beans.) I have heard that some mushrooms can be used to remove toxic elements from the environment (Paul Stamets 2000, Growing Gourmet and Medicinal Mushrooms), but it is not clear if the toxic elements are transformed or stay in the mushroom. Would the mushrooms from non-organic coffee also contain pesticides?

    Also, the quality of spawn varies depending on the company. Some companies will “water down” the spawn . Be careful and order spawn from a reliable company.

  4. Jon R. Schulz

    Readers should know that growing mushrooms on spent coffee waste and grounds is one of the game changing ideas developed by ZERI starting in 1994 and presented in the book Blue Economy which is an initiative of the ZERI foundation. Here are the web sites: http://www.zeri.org, and www,blueeconomy.eu. Blue Economy plans to help entrepreneurs world wide create 100 million jobs in the next 10 years from 100 innovations from nature. Growing mushrooms on coffee grounds is one of these business cases.

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