How to Grow Mushrooms in Coffee Grounds – Home DIY Guide
If you are curious about growing a variety of mushrooms in used coffee grounds, you have come to the right place.
In this guide we provide a step-by-step handbook to successfully grow mushrooms in coffee grounds.
You can expect to learn:
- the type of equipment you need to lay the correct foundation for your mushroom growing adventures,
- the stages of fertilization and growth along the mushroom growing journey, and
- the many benefits of growing your own mushrooms from coffee grounds.
However, before we jump into the guide, we thought it would be a good opportunity to briefly talk about why we love to get behind these styles of mushroom cultivation.
Why Should you Grow Mushrooms in Coffee Grounds?
When it comes to creating a better future, there is no better way of creating sustainability than using the waste products of one industry to fuel another.
Coffee and its derivative drinks is one of the most widely consumed beverages around the world. According to Statista’s research, in 2020/2021, around 166.63 million 60 kg bags of coffee was consumed worldwide. And the consumption rate is only increasing year-on-year.
As you can imagine, with the large quantities of coffee enjoyed around the world, the resulting spent coffee grounds is significant. So finding an alternative use for the waste products (like growing mushrooms and fertilizing your garden soil) is much more preferable when compared to the alternative of leaving it to occupy space in landfill.
Apart from the satisfaction of contributing to a greener future, growing mushrooms at home is a hugely rewarding process. Not only does it provide gratification of growing your own food for personal consumption and friends/family, there are many health benefits of including fungi in your diet.
Now, let’s get into why you are really here – our instructional guide on how to grow mushrooms in coffee grounds.
How to Grow Mushrooms on Coffee Waste
In this section we are going to take you through the steps to grow mushrooms in coffee grounds in your own home. And what is even better is that there is no requirement for sophisticated equipment or hard to find materials. So let’s begin.
Equipment / Materials Required
- fresh spent coffee grounds (must be day fresh)
- mushroom spawns of your choice
- cut pasteurized straw chopped to roughly the length of your hand
- clear plastic bags (to hold your coffee/mushroom mixture)
- secure plastic ties
- sterilizing alcohol
- sterlized sharp knife (like an X-acto Knife)
Stage 1: Coffee Collection
First step in this journey is to collect your fresh coffee grounds from the cafe. It is important to note that you need coffee grounds used only on that day. Anything older than on the day may result in other unwanted mold sneaking in and over-growing your mushrooms.
IMPORTANT – only collect FRESH coffee grounds used within 24 hours of brewing.
Now you can simply walk in on the day and ask. However, it is likely you will catch the owner off-guard and unprepared – especially if they are busy. Take it from us (as previous cafe owners), it is always preferable if you are given a few days notice, so preparations can be made to store the spent coffee grounds in a place out of the way. It also doesn’t hurt if you buy a cup of coffee or two to support your local cafe!
If you are unsure how to approach your local cafe for their coffee grounds, check out our tips below in the troubleshooting section.
How much coffee waste should you collect? That will depend on the size of your project, however to make things simple for you, we employ a method of calculating out the other materials using the original coffee biomass:
- Coffee grounds
- Pasteurized Straw is 15 – 20% of coffee weight, and
- Mushroom Spawn is 10 % of coffee weight.
So, for example, if you picked up 5 kg of waste coffee, you would need approximately 1 kg of straw and 500 grams of mushroom spawn to grow a successful batch of mushrooms.
Stage 2: Preparing the Materials
To prepare the materials, you should sterilize all the equipment to ensure you eliminate the chances of unwanted substances entering your growing ecosystem.
Make sure your pasteurized straw has been drained of any excess water and combine it with the coffee waste. Ensure to break apart any of the coffee pucks using clean gloves and is mixed evenly through the straw.
Stage 3: Introduce mushrooms spawns into the Spent Coffee Grounds
Now it is time to introduce your mushroom spawns of choice. To do this properly, break it into small pieces and spread evenly around the coffee grounds/straw mixture. This will help the mushrooms spawn evenly throughout your composition.
Once combined, bag up your mushroom/coffee/straw mixture into a sterilized clear plastic bag and seal using an airtight tie.
Turn your plastic bag over and make sure no materials come out. If you find some mixture coming out, you need to redo the tie.
Stage 4: Let Nature Do It’s Thing
Locate a dark, humid temperate area in your house that has a stable temperature sitting around 65 – 75 degrees Fahrenheit (18 – 24 degrees Celsius) to store your plastic bag for 2 – 3 weeks.
Finally, use your sterilized knife to puncture the bag seven times for air holes (approximately half an inch wide). You should aim to create holes:
- 3 times evenly spaced around the top of the bag (the end that is on the opposite of the tie),
- 2 times in the front of the bag, and
- 2 times in the back of the bag.
It is important to move your plastic bag to your dark temperate location first BEFORE puncturing the holes. This is to ensure you minimize the amount of mixture you lose and don’t make a mess through your house.
Through this 2-3 weeks, you should see the mushroom spawn begin to produce mushroom mycelium growth. These are the white mycelium that looks like fluffy spider webs spreading across your mixture.
Stage 5: Nurture and maintain mushroom habitat
Once you can see the mushroom mycelium takeover your mixture, the next stage is the exciting part. You should be able to observe baby mushrooms to develop. They will look like little pin heads beginning to shoot up from the mixture.
It is at this point you can carefully move the plastic bag to a lighter area of your house that will receive indirect sunlight. It is important that the bag does not receive direct sunlight, otherwise it could upset the ideal growing conditions of your mushrooms.
At this point you can also widen the holes in the plastic bag. We recommend opening the holes to a maximum width of 2 inches to prevent the mixture from spilling out.
Again, widen the holes only AFTER you have moved your plastic bag to minimize the amount of mixture loss.
To maintain the humidity, use a spray bottle to lightly coat the mixture two times per day. Once in the morning and evening.
Stage 6: Enjoy your Homegrown Gourmet Mushrooms
Now is the moment you have been waiting for – enjoying the delicious mushrooms you have so lovingly cultivated from ground coffee.
Depending on the mushroom varieties you have chosen to grow, you will recognize your mushrooms are ready to harvest once the tops of flattened (around 10-14 days from the first signs of the baby mushrooms sprouting).
Benefits of Growing Mushrooms on Coffee Grounds
You now have the blueprint for how to grow your own mushrooms by repurposing spent coffee grounds. And if you aren’t like us and already halfway out the door to pick up all the necessary materials to begin your mushroom growing journey, here are a few benefits for you to ponder over and get you more motivated.
Coffee waste is a real environmental concern.
As we mentioned earlier, with world consumption levels increasing, any way to decrease the impact of the coffee industry on landfills and the environment is a win in our books.
The repurposing of the coffee waste as a medium to grow your own mushrooms just makes sense. It has a dual positive impact.
- As we mentioned before, it helps to reduce the volume of rubbish being dumped in our landfill. And if you look at the bigger picture, not only are you helping to reduce the amount of coffee grounds ending up as rubbish, you are also helping to eliminate the plastic and styrofoam that would be used to package up the mushrooms in your local shop.
- By growing your own food, you are stepping your way closer to being self-sufficient and helping to reduce your carbon footprint on this earth.
Sourcing enough fresh coffee grounds for your mushroom growing project is not going to be an issue, unless you are living on a remote piece of land. Locating a coffee shop is simple. Chances are you already have a cafe in mind from your daily commuting around your streets. However, if you aren’t too familiar with your area is the simple manner of pulling up Google Maps and searching for local cafes.
Easy Process – most of the work is done for you
If you are unfamiliar with the coffee extraction process used by most cafes, boiling hot water is pushed through fresh coffee grounds at an intense pressure to extract the wonderful oils and flavors of the coffee bean.
This coffee extraction process effective sterilizes the coffee grounds, and completes most of the heavy lifting when it comes to the mushroom growing process.
For the benefit of those who are just getting into the mushroom growing hobby, when you are using other mediums, such as saw dust or straw, as the primary material to grow mushrooms, you are required to sterilize it.
This process involves steaming the materials or running it through boiling water. As you can appreciate, depending on the size of your project, this task can be dangerous and inefficient.
So with this process effectively complete, you are free to simply and easily create your mushroom growing bundles and fertilize the materials with the mushroom spawn.
Mushroom Coffee Grounds: Trouble Shooting
Below are a few trouble shooting tips to overcome some of the issues that you may encounter throughout your journey.
How to approach café owners
We understand approaching cafe owners can be a bit daunting for some, so we have compiled a few tips below to help you break the ice with your local cafe.
- visit your cafe in non-peak times. This may feel like an obvious tip, however some people may overlook the fact that cafe owners are juggling multiple tasks and employees throughout the day. You can increase your chances of catching the owner for a conversation when they are winding down or not serving customers.
- plan ahead and contact your local cafe a few days in advance of when you need the freshly brewed coffee waste. Allowing the cafe owner to inform their staff that you want the coffee grounds will help you by decreasing the amount of contaminants in the coffee grounds you receive. We know from experience, the coffee waste bin is just that – a waste bin. So to ensure you get high quality coffee waste, the owner can advise their coffee maker not to throw other miscellaneous items in the bin, like dirty napkins or milk bottle lids.
- Become a regular. Cafe owners and their staff love to get to know their customers. It’s part of the service. So the more you can show your face and order your ‘regular’ cup of coffee, the more likely they will say yes to providing you with the coffee grinds.
- Give the cafe owners with containers or bags to collect the coffee grinds in throughout the day.
So there you have it – a comprehensive step by step guide to growing mushrooms from waste coffee from your very own home.
There are so many fantastic benefits to be had with growing mushrooms using this process. Such as using inexpensive equipment, positive environmental impacts and becoming self sufficient by growing your own food.
Even though it may feel daunting, many cafe owners would love to support you by providing you with the resultant waste from the coffee brewing process. Not only does it reduce their carbon footprint, but it also helps them reduce their rubbish removal costs.
It truly is a win-win for everyone involved.
Let us know about your mushroom growing journey and if you encountered any issues that we can help out with.