Mushroom Cultivation: 5 Common Mistakes to Avoid

Failure is part of the process when learning any new skill. Mushroom cultivation is no different. Here at the Fungi Academy, we have learned many lessons from failures over decades of mushroom growing experience so that you don’t have to! 

Outlined below are what we’ve come to recognize as the most common mistakes experienced by beginner mushroom cultivators. Growing mushrooms becomes a much easier process once you avoid these errors.

  1. Not understanding sterile workflow
  2. Being impatient
  3. Don’t cut corners
  4. Create favorable mushroom growing conditions
  5. Succeed first, experiment later
  6. Additional mushroom cultivation advice
  7. Conclusion

Not understanding sterile workflow

Contamination is the most common form of failure when cultivating mushrooms. Incorrect sterilization is the lead cause of contamination.  All life on Earth competes to survive, so provide your mycelium with the best environment in which to thrive. When cultivating mushrooms it’s important to limit the number of microorganisms competing for the same resources.

Contamination from our breath, clothing, and skin can all mean the end of what was otherwise a perfect mushroom cultivation procedure. Sterilization comes in many forms, so here are some important things to remember:

Gear up

Use clean protective clothing, a face mask and gloves. You don’t need to have a lab coat, any clothes that are freshly washed are good. Your clothing can carry all kinds of spores and other invisible contaminants.

Mushroom cultivation outfit

Use aseptic solutions

For an alcohol spray, as close to 70% of alcohol to water is the preferred ratio. Hydrogen peroxide (H₂O₂) is also an ally and kills any unwanted competition.

Treat all equipment, work surfaces, containers, and gloves with alcohol before any work commences.

Continue to apply alcohol spray throughout any procedure to mitigate the risk of contamination. Important: Sterilization with alcohol only happens once it has fully dried by evaporation, so be patient.

Sterilize the substrate

We bow to the almighty pressure cooker for our substrate sterilization. It’s a core element for our mushroom cultivation process. Depending on what substrate you’re using, cooking it at 15psi. for 15-70 minutes will free it of any microorganisms looking for a feast!

Pressure cooker

Pro-tip: if you can’t get a pressure cooker that reaches 15psi, you can cook your substrate at 10psi and multiply your cooking time by 1.75. Always operate with caution!

Use proper mushroom cultivation equipment

When performing culture transfers, having the proper equipment helps. While HEPA filters and flow hoods are the most effective, they are also the most expensive.

A still air box (SAB) is an affordable alternative. For a beginner, a SAB is really all you need. So don’t worry too much about getting a flow hood immediately. 

Still air box

IF you are really serious about growing mushrooms from spore to ready mushrooms, then you need a pressure cooker. So many people have asked us how to do without it. Do yourself a big favor and get a good pressure cooker. This is one of the biggest and most important investments for a home mushroom lab. You can get them cheaper if you look for used options.

Sterilize your tools

When dealing with liquid cultures or agar transfers, flame sterilization is the best method. Heat the end of your syringe or scalpel with a flame until it is red hot after it touches any surface.

Remember to let it cool before resuming so that you do not kill your fungal friends!

Sterilize your scalpel

Pasteurize your supplements

Again, this is something that will vary depending on the supplement you use. Coldwater pasteurization with limestone (or soap), hot water pasteurization, and steam pasteurization are all common techniques to kill off rival fungus and bacteria. This prevents any unwanted competition during the fruiting stage.

Because sterilization occurs at every step of the process, it is essential to be diligent at all times. The last thing you want is to waste your time, energy, and resources because of contamination on the final stage! 

Being impatient

While speed and efficiency are important at certain times of mushroom cultivation, it’s essential that you have a controlled, methodical approach.

First-time cultivators are always eager to get to the finished product, but growing mushrooms is a meticulous and thorough process that should not be rushed. Patience is a virtue in life as when cultivating mushrooms!

Waiting for mushrooms to grow

Recommended procedures:

  • Always allow your substrate to completely cool before inoculation with mycelium
  • If storing mycelium in the fridge, allow it to warm to room temperature before transfers
  • Ensure your mycelium has fully colonized your substrate before starting the fruiting stage
  • Limit exposure to air by gathering all necessary materials and thinking through every action before execution.

Don’t cut corners

There is often a temptation to cut corners in the mushroom cultivation process in order to save money, time, and materials. However, this practice can actually have the opposite effect.

Overcompensate with sterilization (at least in the beginning)

There’s no such thing as an over-sterile environment or substrate. This means using your 70% alcohol solution liberally and a little bit over pressure-cooking your substrate.

Cutting corners here will most certainly lead to contamination and render the entire process a failure.

Know where to save money

Like most things in life, higher initial investment in mushroom cultivation will save you more in the long run.

Equipment that reduces the chance of contamination, like a proper pressure cooker, might be more expensive but will prevent you from wasting your time, energy, and money on batches that yield no mushrooms.

Mushroom cultivation first, optimization comes last

Too often we have seen people try to maximize their outputs with minimal inputs. This means trying to stretch their mycelium, substrate, and supplement to its full potential in order to get the highest yield. Don’t be this person!

As a beginner, always use more than you think you need until you’ve mastered your technique. Work backward towards optimization once you’ve fully grasped your technique.

Attempting perfection from the onset will only lead to more mistakes.  

Create favorable mushroom growing conditions

There is no blanket strategy for growing mushrooms. Every mushroom species is unique and thrives under different conditions.

To grow mushrooms effectively, you must adjust the environment to meet the needs of each individual species. The wrong environment will quickly lead to contaminated cultures. It is very important to always check the requirements for each different strain of mushrooms that you grow. 

Mushrooms grow in a variety of habitats around the world, so each one requires separate attention. The most critical aspects are:

  • Air and ground temperatures
  • Humidity
  • Light conditions
  • Sufficient fresh air exchange (FAE)

Not having sufficient fresh air exchange is one of the most common reasons why mushrooms or mycelium does not grow well. Mushrooms that don’t have enough FAE tend to grow small and elongated. Don’t suffocate your mushroom friends, get them some fresh air.

Mushroom growing fresh air exchange

If the mycelium has colonized all the top part of your containers or jars, but a part of it in the bottom is uncolonized means there is not enough oxygen in the bottom. This is because carbon dioxide is heavier than oxygen and it has gathered at the bottom of the jar. We like to turn our mycelium jars upside down when this happens.

Succeed first, experiment later

Experimenting with mushroom cultivation techniques is one of the most enjoyable and vital aspects of being a seasoned mycophile. But do not get ahead of yourself! Stick with proven methods until you’re confident and understand the entire process of growing mushrooms from spores.

Only once you’ve mastered the technique and have an abundant source of materials should you begin to think about intervening. You need to have a firm grasp of the process before you can properly identify and isolate experimental controls.

Mad Science Mushroom Experiment

When you feel comfortable and have the means, experiment with different:

  • Supplements – Do your mushrooms prefer coffee grounds or coconut core?
  • Substrates – Does your mycelium thrive on straw, wood chips, manure, or something else?
  • Environmental conditions – Does altering the humidity produce better results?
  • Sterilization procedures – Can you save time and resources by doing less?

Experimenting with mushroom cultivation is how we all learn and grow in this field together, but it’s wait until you have an intimate understanding of your limiting factors. 

Additional mushroom cultivation advice

There are some mistakes that can only be avoided with the experience that you gain by cultivating your own mushrooms. Here are some more tips that will dramatically increase your success rate:

  • Learn how to identify early signs of contamination. It will save you time and money. As soon as the contamination is spotted the contaminated item should be completely removed from the growing area.
  • Ensure your substrate is not too wet or too dry. It should be damp but not wet, and a gentle squeeze is enough to release a few drops of excess water.
  • Label your jars and samples with species, date, and batch number to avoid confusion.
  • When in doubt, stick to the technique that brought you success
  • When working with spores, ventilate the work-space once finished and samples are secure.
  • Thermogenesis can happen when the mycelium is decomposing organic matter. The temperature in your substrate can become higher than the air temperature in the room, potentially baking and killing your fungal friends.


Never be afraid to make mistakes, it’s one of the most effective ways to learn any new skill. However, avoiding unnecessary mistakes is always a prudent practice and will save you money, time, and frustration in mushroom cultivation. 

Remember to sterilize your environment, practice patience, be liberal with your resources, adapt your environment, and experiment only after success. This way you will bypass the most common mistakes made by beginner cultivators and have a head start on becoming a bonafide mycophile!

Do you know of any other common mushroom cultivation mistakes that should be added to this list? Please let us know in the comments below.

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Join our upcoming Online Sacred Mycology School to learn how to grow your own edible, medicinal, and sacred mushrooms! 

30 Responses

  1. At each stage of the growing process,pay attention to that step only. Get those fruiting bodies out of your mind. Nature will take care of the rest, assuming you provide her with the right causes and conditions to produce those fruits. So, just basically be mindful along the way. For me, that’s become part of the joy and satisfaction of growing.

    1. You want pasteurized substrate not sterilized if you sterilize your substrate you make it very vulnerable to all contams if you pasteurize and mix casing into it and evenly mix it with your colonized spawn grain its almost impossible to get contamination and it will grow twice as fast

  2. So growing mushrooms only inside, what about banana stalks and rice stalks, how do you classify these kind of mushrooms. Thanks

  3. I think I may have taken my mushroom bucket out of the incubation process too early. It looked completely colonized, but this is my first time. Can I put it back in the incubation process after two days of air and indirect light? Thank you in advance!

  4. How do I know when the mycelium run stage is complete snd its time to move on to the next stage? Thanks.

  5. I heard about mushrooms consume oxygen I use a bubble humidifier. Hint fill 1/4 pure water 1/4 hydrogen peroxide which turns to oxygen and pure H2O plus keeps things sterile fights contamination provides sterile water small amount of oxygen have found great success with this method

  6. Zozo here a mushroom grower since 2017. The fisrt time I started to grow mushrooms at my farm everything went well. I did them straight on the ground and i didn’t experience any contamination I harvested about 3 kgs everyday. But as I continue growing them in buckets the contamination appeared. I am having a big wendy house which I devided into two sides. The first side is for pestorization, inoculation and its very clean and tidy. And second one for growing with an aircon inside to control the temperature. But from the 15 buckets 3 of them is contaminated. I tried everything to make sure that everything is 100% clean and the subtract is not wet or dry and I pestorize the subtract correct in a boiling water for 10 minutes. I’m in need of help to be less contamination good people. I’m growing Oysters and now busy with shiitake in logs.

    1. Zozo I think the problem you are having is your sterilization process. I’m positive 10 minutes isn’t enough time. If your cooking your substrate either by pressure cooker or just in boiling water you need to be at optimal sterilization temperature for at least 90 minutes, sometimes I can get away with 75 but I would recommend using the whole 90 minutes to ensure no living contaminants occur. I would start with that if you’re still having problems then check your innoculation process. That is the only place I’ve ever had an issue but it was due to my error in proper sterilization, trying to rush processes and learning the hard way. Good luck hope you solve your problem.

    2. pastirize your substrate for a minimum of 90 mins if using coco for tubs . but if your using bags steralize for 90 mins at 15psi in a pressure cooker and no bad shit will be left . or a little trick is to put some dry casing on the top of your substrate so the mold or bad bacteria can grow.

      1. The best way to manage temperature is to grow a variety of oyster mushroom suitable for your climate and season. For instance, pink oyster mushroom likes warmer tropical climate and a variety of blue oyster likes temperate and cooler climate. By growing the right variety there’s less of environmental temperature control you have to do. This equals less energy (often monetary investments) input.

        At Fungi Academy, we have incubators for the spawn colonization stage. But at home, you can easily make this by getting a cooler pox or an old broken refrigerator. This helps to keep the temperature more stable.

        Mush love and I hope this helps.

    3. How do you pasteurize your substrate? You must not pour water over 180 degrees then it tips to sterilized you don’t want that you must keep the temp in between 150 to 180 so it pasteurized

  7. Is it possible to give too much humidity during mycillium growth stage….i upgraded my fogger system and i think it may be a little much? It soo effective it is causing puddles of water on the bottom of my tent! I mean the conditions are perfect according to my hydrometer. 80 degrees 99 percent humidity. ..obviously it cant read any higer but im just worried its too much humidity. .??

    1. Humidity can be too much, because it will encourage microbial growth in the puddles. Maybe scale back to 90%-95% humidity.

  8. Hello, I have innoculated 4 bags, with a cotton plug at the bag opening. The mycelium is steadily growing towards the bottom with clear color difference in the non consumed color of the straw. The white mycelium is NOT pure Bright white as seen in pictures. There are patches of white, more like cobweb whites. If it doesn’t turn completely white, what might I be doing wrong?

    I am not using breather bags, nor I have punctured the bags. Could this be a reason?

  9. I think I moved my block to the fruiting chamber too soon. I thought it was ready but I’ve seen others and theirs is much more white than mine. It’s been in the chamber for 2 weeks now with no pinning. Is this a failure and do I need to just toss it and start over or can it be saved? Can I put it back in the dark and warmth and hope that it fully colonizes at this point? Please advise.

  10. As a first time grower starting from liquid culture i learned quickly about having a sterile environment. I broke down and built a decent size laminar hood, build a dedicated lab and following the same process, as did prior. I was able to generate uncontaminated grain spawn. If it’s too expensive to build or buy a Flow Hood, build a simple glove box.

  11. Can anything bad happen if you use way too much liquid spore solution? A friend of mine put a whole syringe in a bag that only needs ten ccs

    1. You don’t want there to be a pool of liquid at the bottom of your spawn container. Also, spores need mating so do not shake the jar/bag after if you use spore solution. Good luck 🙂

  12. Im just starting i have 9 dif strains of sporrs and my 1st and secnd try with bags they turned a yellow. Heat around 72 in cupboard near ground and i did not have inoc ports in em so went threw the heppa filter is it that lil hole i make in it that the contaminates getting in

    1. You should definitely close the little hole where you inoculated with some tape. My guess is that the bags were not sterilized properly or the spore syringes were not clean. Maybe increase the time of your sterilization.

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