What Is Hydrogen Peroxide and Why is it Used in Mushroom Cultivation?
According to Wikipedia, hydrogen peroxide is a clear and odorless liquid similar to water with a strong oxidizing capacity. Due to its oxidizing properties it is used as a bleach or cleaning agent. For consumers, it is usually available from pharmacies at 3 and 6wt% concentrations. Commercial grades from 70 to 98% are also available, but the latter require special care and dedicated storage. Hydrogen peroxide decomposes into water and oxygen while this process is thermodinamically dependent. This means that hydrogen peroxide decomposes slowly at low temperature while its decomposition is fast at high temperatures. Uses of hydrogen peroxide include: domestic, therapeutic, explosive devices, as a rocket propellant, etc. I will list here some of its domestic uses:
- between 3%-8% it is used to bleach human hair
- used to whiten bones
- 6% is useful for disinfecting cuts and to stop bleeding in superficial cuts
- it can be used to clean tile and grout on floors
- at a concentration of 35% it is used as an antimicrobial agent
Hydrogen peroxide in a certain concentration proved to be efficient in killing living cells and it is currently used against contaminants found in the compost designed for mushroom cultivation. However, the proper concentration seems to be an essential factor for destroying simple organisms such as bacteria, yeasts, and other contaminants present in the substrate but without affecting the multicellular mushroom mycelium. Therefore this method has the advantage that allow you to pay less attention on overall contamination.
As far as I know, and underlined by Randall and others, commercial hydrogen peroxide is obtained chemically (but there are also natural ways to obtain hydrogen peroxide). Personally, I didn't used this method because I always considered some of the traditional techniques to cultivate mushrooms to be organic and therefore healthy. However, today I will get a bit deeper into this method and I will analyse this aspect too and I will discuss it bellow.
|Randall R. Wayne: The inventor of |
hydrogen peroxide method
of growing mushrooms
Pros and Cons of the peroxide method
According to Randal hydrogen peroxide acts to some extent against all commonly-encountered airborne contaminants of mushroom culture and does not kill established mushroom mycelium or interfere with its growth and fruiting. This has the advantage to reduce the need of costly and elaborate facilities and equipment for environment contamination control so much needed in traditional mushroom cultivation. However, what peroxide does NOT DO is to eliminate all need for concern about sterile technique in isolating mushroom tissue fragments and does NOT kill established live multicellular organisms (such as green mold) beyond a certain size. It will kill isolated spores, yeast, and bacteria that find their way into your cultures. In addition, peroxide does NOT protect the mushroom mycelium itself from aerobic contaminants.
Health aspects of the peroxide method
As Randall stated, commercial peroxide is prepared chemically, it probably would not be considered compatible with organic certification standards; however, he considers the use of peroxide to be in the spirit of organic cultivation because when added to the substrate decomposes entirely into water and oxygen while there can be no trace of the added peroxide left in the mushroom crop. Besides, hydrogen peroxide itself is found naturally in all aerobic living organisms and in a variety of natural environments.
Materials and method
According to Randall's method for growing mushroom you will need the following:
- a balance for weighting
- kitchen plastic bags
- a pot for boiling water
- 5 gallon bucket
- mushroom spawn
- substrate material (pellet fuel, recycled pelletized paper fiber, etc -with few exceptions: see below)
- 3% hydrogen peroxide
Peroxide will provide little or no benefits to substrates that still have a great deal of biological activity, such as compost or pasteurized straw, or fresh wood chips that have been treated with boiling water. The first material suitable with this method seems to be was pellet fuel for wood pellet stoves. Especially because this substrate comes previously heat-treated, so it will not cause peroxide to decompose. You need also to look for a brand of pellet that does not contain any additives. Another material used by Randall with peroxide was recycled pelletized paper fiber. A material that does NOT work with peroxide is raw sawdust.
A. Preparing the substrate with peroxide
- Take a 5 gallon bucket with a lid and clean it thoroughly.
- Next rinse the bucket and its lid with boiling water
- Place the bucket on a scale and scoop in about 8.0 pounds dry weight of pellets (hardwood) or 6.0-6.5 pounds (softwood pellets)
- If you are using a solid denatured nitrogen source you may use it at this stage
- Add your lime to the pellet fuel
- Boil in a covered pot half the amount of water you want to add to the pellets. I usually boil 3.5 quarts (3.5 liters) for 9.0 lbs of oak fuel pellets.
- When the water has boiled for a minute, set the lid of the bucket on one side and pour the boiling water over the substrate. Seal the lid and mix the substrate.
- Boil in a separate covered pot the other half of the water you want to add to the pellets. When the water has boiled for a minute set this pot aside to cool with its cover in place.
- Set the bucket of substrate aside to cool, with the lid in place. Cooling usual takes several hours.
- With a boiling water rinsed measuring cup, add about 1/2 cup of 3% peroxide solution to the pot of cooled, boiled water you've set aside.
- Pour the peroxide mixture into the cooled bucket of substrate and mix thoroughly. This gives a final peroxide concentration of about 0.03%, or a one to one hundred dilution.
- Let the substrate finish cooling to room temperature. It is now ready to use.
B. Adding supplements
If you are using sources of nitrogen supplements such as millet or rice bran, you will have to pressure cook them. While still hot, the sterilized supplement gets poured into the cooling pasteurized substrate. This is necessary to eliminate the the endogenous peroxide-decomposing enzymes before pasteurization. Other supplements that are considered natural and that do not need sterilization include: human urine and animal urine. Calculating how much supplement to add you'll find out by consulting Stamets's Growing Gourmet and Medicinal Mushrooms.
C. Inoculating supplemented sawdust
- Inoculate the pellet fuel sawdust by braking up the spawn briefly, then pouring it directly in the container with the substrate. I close the lid and mix everything together.
- I pour the mix into bags and then twist the mouth of the bag closed and seal it with a twist tie.
- Lastly I compress the sawdust by pressing it down on the bag, gently but firmly.
- The bag is ready for incubation. And from here on out I'm following standard mushroom growing procedures.
Taking a closer look to the inventors overall image we know that he is a scientist in Biochemistry, a field that is particularly relevant to the topic treated here. I personally agree that the word of a scientist weights more than the word of those without any connection to science. With that said, Randall's peroxide method of growing mushrooms looks good according to my point of view. It has the advantage that significantly reduces potential contamination of substrate, while adding hydrogen peroxide to it decomposes into water and oxygen, that seems to be environmental and human health friendly. However, I'm not 100% sure that a commercial product such as hydrogen peroxide derived from chemicals may not cause any harm to human health. Therefore I still encourage growers to follow traditional mushroom growing methods.
What is your opinion related to growing mushrooms with hydrogen peroxide? Did you used this method? What about its efficiency? Please leave a comment and let us know about your experience. If you like this article please give it a 'Like'.
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