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Growing Oysters on Waste

Growing mushrooms on wastes has a huge potential! In the city you'll find lots of materials to grow them on: paper, coffee grounds, spent tea bags, hay, dry leaves or sawdust; while in the countryside the agricultural wastes are piling up. 

Would you toss food to the dumpster? I bet no, especially when thinking about so many poor countries out there struggling for food. Ok, let me ask you again: would you throw $ to the dumpster?
Guess what? many out there get rid of tons of $ without knowing this little dirty secret:

paper ---->food ---->$

Why toss tons of cardboard, imagine about those giant Walmart-like stores storing in their back yards piles of paper. Do they recycle that? maybe -I don't know, but definitely there are lots others tossing that paper. Paper is made out of cellulose which derives from the pulping process. With mushrooms we can simply turn this into food and sell that to restaurants or feed entire families.

What type of paper is it suitable for mushroom cultivation?
Generally all type of material that includes cellulose. I prefer to use cardboard paper because it's not treated with who knows what chemicals. However, in order to be sure of this first I used to wash the paper and then use it in mushroom growing. Although growing oysters on cardboard paper is labor (as you may see below) it is recommended in those areas where sawdust or straw is not available.

In the past led was used as part of the ink used in newspaper or book publishing so i wouldn't recommend any of that. Oyster mushrooms are able to accumulate heavy metals and any pollutants available in the air or in the substrate on which they grow therefore precaution it is best.

Steps to follow:

1. Place the cardboard in hot water (50-60 C /122-140 F) for two hours trying to maintain the temperature at the same level.
2. Let the material to cool down (25-30 C /77-86 F).
3. The heat treated and cooled material has to be squeezed so that no water drops remain after this process.
4. The material has to be 'opened up' until it gets back to its original shape.
5. The paper is then mixed with gypsum (~ 2%)
6. Add the oyster mushroom mycelium to the mix
7. The material than is placed into a plastic bag
8. Holes are made on its surface for gas exchange
9. Leave the sac for 2- to 3 weeks at 15-23 C /59-73 F (indoors or outside)
10. Once primordia start to mature spray the sac with water (2 times/day)
11. After 3-5 days you may collect your mushrooms.
12. Wait another 10-14 days for a second wave of mushrooms and collect them as well.

As you may see growing oyster mushrooms is very easy. Even a 5 year old can do it. It's pretty much like cooking. You've got the ingredients then you mix them up throw everything in a pot place that on fire then you drain them like pasta. Next you add flavor to it and let that spread everywhere.


Another great substrate found in the cities is coffee grounds. This always reminds me of the Back to the Roots story. Founded by Alejandro Velez and Nikhil Arora, 'Back To The Roots' it's a great example showing the power of mushroom success. As students of UC Berkeley back in 2009 Alejandro and Nikhil were heading into the corporate world of investment banking and consulting. However, two months away from graduation they stumbled upon the idea of the benefits of growing gourmet mushrooms on recycled coffee grounds. They started to grow oyster mushrooms on coffee grounds in a fraternity kitchen and got to collect, divert and reuse 3.6 million lbs of coffee grounds collected each day from local coffee shops. They made kits currently sold at over 300 Whole Foods across US, help families grow fresh food at home and sustain 10 urban schools and community gardens by donating them premium soil amendment based on spent coffee grounds. Well, what a nice picture. They were waking up early collect the spent coffee grounds from different local coffee shops which practically has no value for coffee shop owners -it was tossed at the dumpster anyway. And these two guys knocking at their door to pick up the garbage for free. Besides their spent mushroom substrate was sold as premium soil amendment. To use the same waste twice and to get an income from it it's a brilliant idea and reflects the mushroom power. Check out their story:

They are easy to grow on a wide range of agricultural wastes. You may use pretty much any plant that was once alive from hay to corn plant stalks, dry leaves, straw, been plant waste or cotton hulls. Best is when what you have available is free but if you're going to turn this into a business the free stuff may or may not be your best choice. The good news is that for starters oyster mushrooms are best to start with because even if you'll do mistakes they are going to be generous with you. They are tolerant and even when you'll throw the spent substrate on the trash outside it's still going to fruit like crazy. Once you put them up they will give you several flushes (usually 2-4 or even more). When growing oyster mushrooms I see two types of growth:

  • Classical growing -the low tech [without equipment]
  • Modern growing -the high tech [with equipment]

Now, this classification is not clear because you may start low tech and get somewhere in between low and high tech. It's an evolution, a process that depends on each grower. The differences are expressed in terms of yield. If you want to grow them for yourself as a hobby go for classical but if you want to turn this into a business i'm afraid that you'll need to equip your grow room with something able to give em a boost. Also if you're just starting with mushroom growing go for classical so you can see the difference so you can see what means to add a mister in that grow room.

The Closed Loop
A huge advantage for farms out there interested in the approach of a sustainable type of agriculture: I call it the closed loop.

Step 1: you grow your veggies and collect your crop. At this point what you have left is agricultural waste (corn cobs and stems, cottonseed hulls, sugarcane waste, etc).

Step 2: use this waste to grow mushrooms. At this point you collect your mushroom crop.

Step 3: use the spent substrate from your mushroom crop -turn it into compost with worms. Let them do what they know best.

Step 4: use the compost as a soil fertilizer for your veggie crop.

The investment is low or depends on how you want to start: small or big. Of course to start small is the best way because to build experience takes time. You can actually start this with $100 in your pocket if you already have a grow space and agricultural waste around. Basically there are several stages in developing such a business with low investment. Most important is to discover the difference between the low-tech and the other stages and observe how the competitor presence and yield is affected. Check out my OTHER POST to learn more about what means to turn this into a business.

Grow them for you and your family. Growing your own brings you truly fresh and healthy food on your table. By contrast, supermarket mushrooms are different because SOME mushroom producers are using various types of chemical substances designed to get rid of competitors when the substrate is freshly inoculated with fungus mycelium. This is important for them in order to get a high yield in terms of mushroom production. Such chemicals are not a healthy choice. However, best is to grow your own food the healthy way.  Go organic and you'll be happy!

Mushrooms are healthy. Many cultivated mushrooms species are considered 'functional foods' this means they provide nutrients to your body and act as a therapeutic force too (e.g., shiitakes, oyster mushrooms, ear mushrooms, etc). Among other important nutrients and therapeutic substances, they are rich in proteins, have no cholesterol, contain polysaccharides with huge medicinal value, terpenes, other active ingredients with medicinal value, vitamins and minerals. The best choice for those that want to live a healthy life.

It's rewarding. Doing what you like is rewarding. Simply by watching the mushrooms grow under your own eyes it's an amazing feeling that I recommend you to experience.

It's a way to make new friends. A hobby reunites people enjoying the same feeling or interest. Making friends and sharing your experience as a grower with them it's important because this may be a way to learn from others.

Do I mentioned business? Many people are thinking about mushroom growing as a powerful choice to achieve financial freedom. Examples are plenty. I'll let you imagine.