Used coffee grounds

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Used coffee grounds in boxes.

Used coffee grounds are the waste product from brewing coffee. In the late 19th century, used coffee grounds were used to adulterate pure coffee.[1] Initiatives have succeeded using coffee grounds as a substrate for the cultivation of oyster mushrooms.[2][3] Used coffee grounds have other homemade uses in wood staining, air fresheners, and body soap scrubs.[4] They may also be used industrially in biogas production or to treat wastewater.[5]

In gardens[edit]

Composting worms moving about in used coffee grounds.

In gardens, coffee grounds may be used for composting or as a mulch[4] as they are known to slowly release nitrogen into the soil. The coffee grounds are rich in potassium, magnesium and phosphorus. They are especially appreciated by worms and acid-loving plants such as blueberries,[6] although due to acids being leached from the grounds while in use, they typically have a neutral pH. Used coffee grounds are particularly noted as a soil amendment.[7] Gardeners have reported the use of used coffee grounds as a slug and snail repellent,[4][8] but this has not yet been scientifically tested.[5] Some commercial coffee shops run initiatives to prevent the grounds from going to waste, including Starbucks' "Grounds for your Garden" project,[9] and community sponsored initiatives exist, such as "Ground to Ground".[10]

Use in fortune telling[edit]

In divination and fortune-telling the patterns of coffee grounds are used for predictions.

See also[edit]


  1. ^ Pendergrast, Mark "Uncommon grounds : the history of coffee and how it transformed our world" 2010 Basic Books. ISBN 978-0-465-02404-9
  2. ^ (in Dutch) Zelf oesterzwammen kweken op basis van ... koffiegruis?
  3. ^ (in Dutch) Oesterzwammen en koffiedik?
  4. ^ a b c "Don't Throw Out Your Leftover Coffee Grounds!". Huffington Post. 4 August 2014. Retrieved 25 December 2014. 
  5. ^ a b Chalker-Scott, Ph.D, Linda (2009). "Coffee grounds— will they perk up plants?" (PDF). Master Gardener. Puyallup Research and Extension Center, Washington State University. Retrieved 25 December 2014. 
  6. ^ Martin, Deborah L; Gershuny, Grace, eds. (1992). "Coffee wastes". The Rodale book of composting. Emmaus, PA: Rodale Press. p. 86. ISBN 978-0-87857-991-4. Retrieved January 5, 2010. 
  7. ^ "Coffee Grounds Perk up Compost Pile With Nitrogen". Life at OSU. 10 June 2009. Retrieved 1 April 2018. 
  8. ^ "NORTH COAST GARDENING: Winter vegetable growing". Eureka Times-Standard. 24 December 2014. Retrieved 25 December 2014. 
  9. ^ "Coffee for Your Plants? Starbucks Offers Free Coffee Grounds for Gardeners". Retrieved December 13, 2015. 
  10. ^ "About Us | Coffee Grounds to Ground". Retrieved October 26, 2011.