Growing Gourmet Mushrooms at Home from Waste Coffee Grounds

, written by Adam Sayner gb flag

Growing mushrooms

"Tried growing mushrooms before, and it didn't work" – if I had money for every time someone has said that to me I'd be a very rich man...and probably no longer a mushroom farmer! Mushrooms are notoriously unreliable to grow, partly due to the mass-produced low quality kits that people often try. Almost mystical organisms, they seem to pop up in the wild in an unpredictable way, often only appearing for just 5 or 6 days before vanishing back into the ground again, not to be seen in the same spot for another year or three. Yet, despite a poor reputation amongst home growers, by using a particularly simple technique and getting a bit of insight into how mushrooms grow, it is possible to successfully grow your own gourmet mushrooms at home. So how exactly are mushrooms cultivated? How can you have success at home? And more to that point - what's all this got to do with waste coffee grounds?

How Mushrooms Grow

Firstly, you must understand the life cycle of a fungus. Similar to the fruits produced by a tree, mushrooms are the reproductive fruits of a dense, root-like network of cells, called 'mycelium'. In the wild, this white network of fine threads grows out it all directions, breaking down its food into simpler molecules to further fuel its growth. When it runs out of food, or is put under some other form of environmental stress, it switches into survival mode and produces mushrooms in order to release its spores to the wind and find a better place to live. Fortunately for us humans, it's possible to recreate and manage this life cycle, and by doing so you can nurture many a fine crop of mushrooms for the table!

Mushrooms

Now, it must be said that growing your own mushrooms is definitely more difficult than growing nearly any other crop if you use the standard methods. Mushroom farming normally relies on significant pasteurization equipment and climatic control. This can be hard to recreate at home without spending a fortune.

Growing Oyster Mushrooms

The best advice for success is to start by growing Oyster mushrooms, the easiest and most forgiving variety for any home cultivator to grow. Next you must consider the growing medium. The most common materials to grow Oysters on are usually freshly cut hardwood logs or shredded straw. Growing mushrooms on logs can be quite hit or miss and will take up to a year for your first harvest. Growing on straw requires you to pasteurize the straw first, to kill off resident micro-organisms that will compete with your mycelium.

Oyster mushrooms

This is where coffee comes in. The beauty of growing mushrooms on fresh coffee waste is that the substrate is already pasteurized by the coffee brewing process, so you can bypass the whole pasteurizing step and get straight into the inoculating. Plus, spent coffee grounds are a huge waste resource, and are packed full of nutrients which your Oyster Mushrooms love to grow on.

Inoculating

Firstly order your spawn in. You'll have greater success if you use a high spawn: coffee grounds ratio. To begin with, I'd recommend using around 500g of oyster mushroom spawn to each 2.5kg of spent grounds. If the vendor you purchase the spawn from also sells filter patch grow bags, get one of these too. They will increase your chance of success by reducing contamination and providing the perfect growing environment inside the bag. If you can't source one of these, you can try using a large 2 litre freezer bag, empty ice-cream tub or milk carton – cleaned out well, and with 4 x 5mm holes cut in the sides.

Mushroom growing media

Coffee collection

Go to a busy café and ask them nicely if they can give you some spent grounds. You'll need enough to fill the bag or container you're using two-thirds full, and the grounds need to be fresh that day. Most cafes will be happy to do this – if you encounter any problems, just ask at another one. Large cafes get through kilos of the stuff every day, and most are happy to see it going to good use. Take it home and (within 24 hours whilst it's still fresh) weigh out 2.5kg of coffee into a clean mixing bowl.

Wash your hands and lower arms well and mix your spawn into the bowl, breaking it up and distributing it evenly throughout the coffee. Now load the mixture into your cultivation bag or container and close it up tight, ensuring you have cut the 4 air holes if you are not using the filter patch bags.

Spawn run

Place your bag/container in a warm (64 – 77°F, 18C – 25°C) and dark place (airing cupboard, under a bed, in a cupboard in a heated room etc). During the next three weeks, you will see the spawn come to life and grow across the coffee grounds - turning the whole mixture white by the time it has fully colonized the mixture. It's a fun time to keep checking up on it and watch it grow from day to day.

Mushrooms

Fruiting

After 3 weeks, your whole bag/container of the coffee and spawn mixture should now look completely white. If you see any areas of green, this is a competitor mold. If it is just a small patch, you can try adding a little salt to the area which should kill it off and still allow the mushroom mycelium to prosper. If the whole bag has gone green, then I'm afraid it's a lost cause and will most likely be caused by poor quality spawn, or by a lot of mold spores having been mixed in with the coffee grounds somewhere along the way. However, if you have used a high rate of spawn, fresh spent grounds and followed clean hygiene, the chances are you will be looking at a nice white bag of mycelium ready to fruit you some home grown mushrooms.

Place it in a spot with plenty of fresh air and a little light – a shaded windowsill or worktop is ideal. Cut a 5cm x 5cm (2in x 2in) hole in your bag/container and spray this area twice daily with water, trying not to allow it to dry out. Mushrooms love damp, humid conditions, and they will outright refuse to grow if it's too dry.

Mushrooms

After a week or so, you will start to see tiny little mushrooms bursting into life. Over the following 5-7 days they will double in size every day. This is a really fascinating time! Each day you wake up to find them larger; looking more and more meaty and ready for the eating. When the edge of the caps begin to turn upwards, it's time to harvest and enjoy the fruits of your labor. Cut at the base of the stems and get cooking!

We're grateful to Adam Sayner of GroCycle for sharing his fantastic method of growing mushrooms on coffee waste with our readers. If you'd like to save yourself the trouble of collecting coffee waste and inoculating the mixture, Adam sells ready-made kits on his website (GroCycle.com). They also offer an online course to help you get started, find out more here: How to grow Oyster mushrooms on waste coffee grounds. If you are based in the US you might wish to check out Fungi Perfecti (http://www.fungi.com) for spawn.

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Comments

 
"A very interesting and easy to understand article."
Satish on Saturday 29 September 2012
"Thank you for the article! How much of a harvest can we expect from the "recipe" above? Once they are harvested, is it possible to start more off from what you had, or does one need to start the whole process over? i.e. Is there anyway to collect and use ones own spawn? "
Ally M on Friday 5 October 2012
"oops also forgot, does it matter what type of coffee grind waste? Espresso, flavored, decaf?"
Ally M on Friday 5 October 2012
"Thanks for the article. I am hoping to grow oyster mushrooms on a combination of coffee grounds and shredded cardboard. Have you any suggestions regarding the ratio of coffee grounds to cardboard please?"
Lindsay Allen on Monday 31 December 2012
"I think you can get atleat 3 harvests from the single mix. Regarding the quantity it would depend on the size of the bag. A 50 kg bag could give yoy 10 kg of cofee grown mushrooms. Happy new year."
Satish on Monday 31 December 2012
"Excellent article! I found this just in time because I just became interested in growing mushrooms while pondering what to plant in my garden for spring. I read that if fresh grounds can't be found you can pasteurize an older mix yourself just like you would cottonseed hulls. Would this work and would pasteurization be needed for fully composted material that is no longer "hot"?"
Wade B on Thursday 3 January 2013
"Hi! Great article :) Please help wit these three doubts regarding growing mushrooms on coffee grounds: 1. If I try to grow on somewhat large scale and ask for coffee grounds from the vendors at the end of the day, will the grounds may have contaminated after being exposed for the whole day? 2. Do I thoroughly mix the coffee grounds and spawn or just let spawn sit at the top of the substrate? 3. Do I sterilize the polythene bag in which I am growing mushrooms using alcohol or boil it? "
Pranshu on Thursday 14 February 2013
"Thank you for the article! I love this article. http://www.mushkit.com/"
MUSHKIT on Thursday 7 March 2013
"If you are in the us check out http://store.farwestfungi.com/mushroom-mini-farms.html I have always had great luck with these guys and they sell a cool little kit for growing mushrooms in newspaper"
KarenS on Tuesday 16 April 2013
"Thank you for this article,may you please come to Uganda on a volunteer basis to aid us in growing mushrooms and connect us to markets"
Innocent Twesigye on Wednesday 17 April 2013
"Very interesting, I like to forage mushrooms and grew them only once, but I should try again as they don't have many wild mushrooms in New Zealand. BTW, I found you by a site that links to other blogs, which it is good except they never put proper credits to photos or the name of blog. I complained and they removed my post but no apologies of course... it is here http://thepancupboard.blogspot.com/2013/04/how-mushrooms-grow.html, one of those blogs that uses other people's articles to get clicks and sell ads."
Alessandra on Wednesday 24 April 2013
"its such a wonderful article. MAY GOD BLESS YOUR WORK"
kayizzi tonny on Monday 13 May 2013
"I strongly believe its not that easy to grow mushrooms, even using a reliable kit could let you down. Its not an easy task to grow mushrooms and we need to take care of many things while growing. Here is one website that could be helpful to mushroom lover www.growyourownmushrooms.net This gentlemen has taken time to put lots of articles together to grow mushrooms, I hope it might help you all in growing mushrooms in better manner."
Erika on Tuesday 4 June 2013
"A Very Interesting and Detailed Outline for mushroom growing, Ive checked out an interesting website http://www.mushroomsource.ca for all supplies and tools , do visit this website"
Michael on Wednesday 10 July 2013
"can you teach us how to make blob mold?"
Liz Prall on Monday 22 July 2013
"Hello, I freeze my own coffee grounds daily until I have enough for spawning mushrooms.Is it still usable? Can I pasteurize these grounds after thawing with any success? Wat is a filter bag? Thank you"
Roger DeBolt on Monday 21 October 2013
"Surely you could microwave the coffee grounds to sterilise them if you were bothered about it? Eg http://britishfood.about.com/od/glossary/ht/sterilizingjars.htm "
Claire on Monday 11 November 2013
"Thanks for wonderful article. I have had somany failures but want to keep on trying. Please tell me how to collect and prepare the spawn. I live in South Africa. Thank You Bart Saayman"
Bart Saayman on Wednesday 8 January 2014
"I am growing my first mushrooms from a kit and and hoping to inoculate some grounds I have been saving up to keep the mushrooms going. A friend told me that if I boil the grounds for an hour and cool then they will be sterile and good to use for those of you asking about using your own grounds! I have little individual pins forming and they are growing rapidly! Im excited to experiment and see i i can successfully keep them growing!!"
Whitney on Saturday 1 March 2014
""spray the area twice daily with water" I don't understand, what kind of water do you use? Tap water, rainwater.... Thank you very much for your answer and for this really very helpful article. "
Veronika Czechmeister on Saturday 15 March 2014
"I think it might be easier for me to steam sawdust and oak "flakes" (from planing). Would that work ?"
charles marriage on Tuesday 15 April 2014
"I live in Canada and am wondering if there is a good Canadian source for spawn?"
James MacKay on Friday 22 August 2014
"I was wondering if I can use the mycelium from one of your kits after its fruited. Will this make suitabke spawn? "
Laura Otterschild on Tuesday 10 February 2015
"I think most people over-complicate things. I've grown Oyster mushrooms on a bale of straw. I poured some fertilizer on it to compost it a bit, then stuck pieces of a sawdust kit into the straw bale, and left it in a shady spot outside. I watered it whenever it got too dry, and it fruited every time we had a good downpour and cooler temps for a few days. I had some rogue mushrooms come up in it too, but they were so different that they did not matter at all. We got many flushes from it."
Laura@fermentacap.com on Monday 9 March 2015
"Can you use a styrofoam cooler to put the bag in for temperature, with a small hole for a fan to regulate CO2 and Oxygen flow?"
Liam on Tuesday 7 April 2015
"It's my understanding if I start my mushrooms indoors a ton of spores will be created. It was suggested not to even put them in the basement if someone watches TV there because eventually you'll develop allergies. "
Fran Martin on Wednesday 20 May 2015
"Hi A very interesting article, I have had fair degree of success by growing Ready to Fruit kits of Oyester mushrooms, out of 10 bales (made of finely cut straw) 5 bales gave about 5 KG of mushrooms of good quality BR NAIR"
Rajshekar on Saturday 6 June 2015
"I like growing mushrooms too but I need expand my area and also how to sell them "
caroline Asimo on Wednesday 10 June 2015
"I have a problem with my mashrooms, they grow and dry before they are ready, and yet i water them two times a day and they are not in a dry place, what could be the problem"
jonah kamwine on Wednesday 24 June 2015
"You can use your own coffee grounds to grow oyster mushrooms with this easy to use kit made by Gourmet Woodland Mushrooms. More details here: https://www.gourmetmushrooms.co.uk/shop/mushroom-recycler-kits/gourmet-mushroom-coffee-grounds-kit/"
Adrian on Wednesday 11 November 2015
"Is shredded bark mulch a good medium to grow oyster mushrooms?"
Gene on Thursday 4 February 2016

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