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How to Grow Mushrooms [Beginner’s Guide]

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Many people are becoming interested in growing mushrooms at home. It is a great way to learn more about fungi and be rewarded with a (hopefully) bountiful harvest. Some varieties are fairly easy to grow with minimal equipment and knowledge, while others are a little more challenging. 

Mushroom grow kits are a great option for beginners. They consist of a fully colonized block of mycelium, which you just need to spray with water to trigger fruiting. In some cases, you will be picking your first homegrown mushrooms in just a matter of days. 

Once you understand a little more about how mushrooms grow, you might want to attempt growing mushrooms from scratch. Sure, there is more that can go wrong, but when you get it right, the results are even more satisfying. 

Read on for our beginner’s guide on how to grow mushrooms from start to finish. It may be simpler than you think! 

Growing Mushrooms 101: Anatomy and Life Cycle

Before we discuss how to grow mushrooms, we will give a brief overview of the mushroom life cycle. This will help you understand the different stages of growing mushrooms, what you need to do, and what could potentially go wrong. 

First, it is essential to recognize that mushrooms are the “fruit” of a much larger organism known as a fungus. The main body of the fungus is made up of a solid white mass called mycelium. You usually can’t see mycelium because it tends to be buried beneath the soil or deep within a rotting log or tree. But when you grow mushrooms, you will become intimately acquainted with it. 


Mycelium is made up of tiny strands known as hyphae. These hyphae start their life as a microscopic spore, which is similar to a plant seed. When a spore germinates, it sends out a single hypha, which joins together with other hyphae to form a network of mycelium. 

When the conditions are right, this mycelium starts to produce mushrooms. They start as a small structure known as a hyphal knot, which develops into a “pin,” then a “button,” and finally, a fully formed mushroom. The mushroom’s role is to produce more spores and start the life cycle again. 

You can read more about this process in our in-depth article on Mushroom Anatomy and the Mushroom Life Cycle.

How Long Does It Take to Grow Mushrooms?

Growing mushrooms from scratch can be a lengthy process, although it is a rewarding one. How long it takes will vary depending on the type of mushrooms and conditions, but you can generally expect it to take at least two months or more.

You can speed up the process by using pre-colonized grain spawn or mushroom grow kits. These are great for beginners as they significantly reduce the time and effort associated with growing mushrooms, and there is far less that can go wrong.

However, anyone ready to take their mushroom-growing skills to the next level will surely enjoy the adventure of growing from scratch. Watching a few tiny spores turn into a generous mushroom harvest makes all the hard work worthwhile!

How to Grow Mushrooms: Conditions and Equipment

Three basic elements are essential for growing mushrooms:

  1. Mushroom spores. This could be a spore print, spore swab, or spore syringe.
  2. A substrate to germinate the spores on.
  3. The right growing conditions.

Depending on the type of mushrooms you want to grow, you might also need some special equipment. Not all items are essential, but they will provide better results if you use them. The only other things you need are patience and willingness to learn.

Here’s how to get started.

Growing Conditions

Mushrooms usually grow in damp or humid conditions. Therefore, you need to create a climate-controlled environment for optimal growth. This is usually known as a fruiting chamber.

You can create a fruiting chamber in many different ways, and the best method will depend on what mushrooms you are trying to grow. Small mushrooms will happily grow in plastic storage tubs, while larger species tend to grow out of plastic grow bags, sometimes known as unicorn bags. These bags must be kept in an enclosed environment like a mini-greenhouse or grow tent.

Unfortunately, the damp and humid conditions that mushrooms favor are also ideal for contaminants like mold and bacteria. Mycelium is very prone to contamination, and this is one of the most common reasons for an unsuccessful grow. Good hygiene practices and physical cleanliness are crucial throughout the growing process to reduce the risk of contamination. It is also best to grow mushrooms in a low-traffic area that won’t be disturbed too often.

Mycelium can grow very happily in the dark, but mushrooms require fresh air and light to trigger fruiting. A little ambient light is sufficient; it needn’t be particularly bright. But if your fruiting chamber does not receive natural daylight, you might need to use a grow light instead.

Equipment and Supplies

We have listed some of the equipment and supplies that are necessary for growing mushrooms below. Some of these are essential, while others are optional and depend on the mushroom-growing technique you choose:

  • Mushroom spores (a print, swab, syringe, etc.)
  • Still air box (see below for how to create this)
  • Isopropyl alcohol 70%
  • Paper towels
  • Disposable gloves and a face mask
  • Microporous tape
  • Agar plates
  • Scissors
  • A scalpel or craft knife
  • Lighter or another flame source
  • Grain (millet, rye, wheat, etc.)
  • Pressure cooker*
  • Quart mason jars with lids, or mushroom grow bags
  • Incubation chamber (see below)
  • Seedling heat mat with thermostat (optional)
  • Bulk substrate (coco coir, coffee grounds, wood pellets, etc.)
  • Cooking thermometer (optional)
  • Fruiting chamber (see below)
  • Spray bottle for misting

*It is possible to grow mushrooms without a pressure cooker, although the results may not be as reliable. We will explain an alternative method in Step 6 below. 

Growing Mushrooms: Step-By-Step Guide

Precisely how you grow your mushrooms will vary depending on your chosen variety. We have provided a general overview of the steps involved but recommend that you carry out further research to learn the specific requirements of each species. 


1. Create a still air box

Professional mushroom growers use a piece of kit called a laminar flow hood to create a clean working environment. It is a large air filter that prevents mold and bacteria from infecting the growing medium and contaminating the developing mycelium. However, this equipment is a significant investment, so most people start out using a still air box instead.

A still air box provides a clean environment and reduces the risk of contamination while you work. It is where you will carry out all of your inoculations and transfers, and there are a couple of ways to make one. 

Most people use a large, clear plastic storage container as their still air box. Some cut two hand-sized holes in the side of the box, allowing them to work inside, although it is also possible to just place the box upside down on a kitchen counter. With the second method, you simply pull the box forward a few inches so it overhangs the counter enough to fit your hands inside. It is easiest to do this while sitting on a chair.

Using the second method can make working inside the still air box slightly more awkward but saves making holes in the side of the container, which you can then use later as your fruiting chamber. It is worth experimenting with both methods to see which you prefer.

2. Inoculate your agar

Agar is a nutrient-dense gel that is ideal for germinating spores. It is made from a type of algae and is often used as a gelling agent in foods. You can either cook your own agar from scratch or save time and effort by buying pre-poured agar dishes. We recommend buying your agar from a mushroom specialist to ensure it has been prepared in a sterile environment and is not contaminated with bacteria or mold. 

Before starting work, put on the face mask and gloves. Then disinfect the inside of your still air box and work surface using isopropyl alcohol and clean paper towels. Disinfect your scissors and scalpel and place them inside the box. Then, peel away the outer layer of the microporous tape to reveal a fresh surface and place that inside the box, too.

Next, disinfect the outside surfaces of your agar dishes. Place the disinfected dishes inside your still air box, but keep them closed for now.

Finally, open your spore print, swab, or syringe. If you are using a syringe, you may wish to disinfect the surface of the barrel. The needle should be sterile, but you can use a flame to sterilize it for a few seconds if you wish. Always use naked flames outside the still air box – isopropyl alcohol is very flammable!

Now you have everything prepared, it is time to inoculate your agar. Remove the lid from one of the agar dishes. If you are using a spore print, use the scalpel blade to scrape a few spores onto the agar. Sterilize the blade with a flame first – do this outside the box. If you are using a spore swab, swish it gently across the agar in an ‘S’ shape.

If you are using a spore syringe, squeeze a couple of drops out onto the agar. Technically, you could skip this step since spore syringes should already be sterile. However, it is still worth testing the liquid for contaminants. Plus, it is exciting to watch your mycelium growing out on the agar! 

Keep the agar dishes open for as little time as possible before closing them up again. If you have traditional-style Petri dishes, you can use a strip of microporous tape to seal up the edges. If your agar is already in an airtight container, this is usually not necessary.

It is best to inoculate several dishes in case one or more of them becomes contaminated. Repeat the process described above, remembering to disinfect anything that goes inside the still air box first. 

3. Incubate your agar

It is best practice to note the date you perform each stage of your grow for future reference. Write the date on the outside of your agar dishes using a Sharpie or simply jot it down in a notebook. 

Next, move the dishes from the still air box to your incubation chamber. You will then need to keep them there until healthy mycelium fully colonizes the agar. Your incubation chamber could be anything from a storage box to an unused cupboard. However, it is essential to choose somewhere clean and enclosed that will not be disturbed too often. 

Depending on what mushrooms you are growing, it might be necessary to maintain a specific temperature within the chamber. You can use a seedling heat mat with a thermostat to keep the mycelium within its preferred range. The optimal temperature will depend upon the mushroom type, so research carefully this before you begin. 

Check your inoculated agar every few days to see whether mycelium is forming. Healthy mycelium is white, and you should see it steadily filling your dishes over the course of several days. You will also need to be on the lookout for contamination during the incubation period. If you see green, blue, brown, black, pink, or orange patches, you likely have contamination and will need to discard the affected agar.

If a dish is contaminated but also contains healthy mycelium, you can perform a transfer and start again (see below).

4. Transfers

If you need to make a transfer, set up your still air box and follow the disinfection procedures described in step 1.

Remove the contaminated agar dish from your incubation chamber and prepare a fresh one. Disinfect the outside of both dishes and place them inside the still air box, keeping them closed for now. 

Take your scalpel and sterilize the blade using a flame – do this outside the box. Allow it to cool for a few seconds. 

Then, open the contaminated dish and cut out a small wedge of healthy mycelium as far away from the contamination as possible. Use the blade to pick up the mycelium wedge by stabbing it in the center, and close the dish immediately.

Then, open the fresh agar dish and drop your mycelium wedge into the center of the gel. Close it as quickly as possible and seal it with microporous tape if necessary. Write the date on the outside of the dish, or add it to your notebook. 

You may need to continue repeating steps 3 and 4 several times until you have a fully colonized, uncontaminated agar dish.

5. Prepare your jars or bags

If you are using grow bags, there is not much you need to do here since they are designed with all the features you need for a straightforward grow. However, if you are using mason jars, you will need to do some preparation.

As mycelium develops, it needs to exchange gases, just like plants and animals do. Therefore, your jars must allow it to “breathe.” The best way to do this is by drilling a few 1mm holes in the jar lids and covering them with microporous tape.

Avoid making the holes too large because too much air flow might trigger your mushroom pins to start forming before the grain is fully colonized. It could also increase the risk of contamination.

6. Sterilize your grain

Mycelium needs plenty of nutrients to thrive, and once it has exhausted the agar, it will need another growing medium. Grains such as millet, rye, and wheat are ideal for this purpose. You can also use popcorn or wild birdseed. Each of these has pros and cons, so do some research before deciding which is best for you. 

Once you have chosen your grain, you will need to wash, soak, and simmer it. How long this takes depends upon the grain, as some are larger than others. Next, you need to sterilize the grain, preferably using a pressure cooker.

Place the washed, soaked, and simmered grain into your mason jars or grow bags and place them in your pressure cooker. If using jars, cover the lids with tin foil to ensure no water gets inside. Stand the containers on some spare lids or a folded teatowel so they do not touch the bottom of the pan. 

Set the pressure cooker to 15 PSI and sterilize your grains for at least 90 minutes for jars or 3–4 hours for bags. Leave them to cool for 24 hours.

If you do not have access to a pressure cooker, you can sterilize your grain jars in a regular pan. Cover the lids with tin foil to ensure that no water gets in, and place them on top of some extra lids or a folded teatowel to prevent them from touching the base.

Fill the pan with cold water to around halfway up the jars and turn on the heat. Once the water starts boiling, turn it down to a steady simmer for about two hours. Check your pan regularly to ensure it does not boil dry. If the water level gets low, top it up with some more boiling water from the kettle. Leave the jars to cool for 24 hours.

Another option is to purchase pre-sterilized grain bags from a mycology supplier and skip this step altogether.

7. Inoculate your grain

Once the grain jars or bags have cooled, you need to inoculate them with mycelium. If you have followed the steps above, you should have some healthy mycelium grown on agar, which you will now add to your sterilized grain. You can also use a spore syringe to inoculate the grains directly, provided you are confident it is uncontaminated.

Disinfect and prepare your still air box and equipment as described in step 1. You should also disinfect the outside of the jars or grow bags as a precaution.

Next, flame-sterilize your scalpel blade - do this outside the box. Then, open one of the fully colonized agar dishes and cut it in a criss-cross pattern to make small squares. Open the first grain jar or bag and tip in the agar. Close it back up as quickly as possible to reduce the risk of contamination.

Seal up any holes with microporous tape and give the jar or bag a good shake to distribute the agar pieces evenly. This will speed up colonization as the mycelium will be more evenly spread and have increased inoculation points within the grain. Repeat the process with your remaining dishes and containers.

It is up to you how much agar you put into each jar or bag. If you only have one dish, you can split it between two or more containers. However, as a rule, the more agar you put into each jar or bag, the faster it will colonize. That said, you should avoid using too much, as this could cause the mycelium to overheat and die. It is also a good idea to inoculate multiple jars or bags in case of contamination. 

Write the date on the outside of the jars or bags, or add it to your notebook. 

8. Incubate your grain

Now, you must wait for your mycelium to colonize the grain. Incubate it in the same conditions as you did with the agar. Depending on the species, type of grain, and temperature, the whole process can take several weeks.

Check the jars or bags regularly for signs of contamination. If you spot anything suspicious, it is best to discard the infected containers. Do not open them inside your growing space, which could risk spreading microscopic spores through the air. Instead, immediately remove the sealed containers from the growing space and throw them away. 

Once the grain is around 30% colonized by mycelium, shake the jars or bags to distribute it evenly. This can speed up the process significantly. Keep checking your containers regularly until the grain is fully colonized. At this point, it should look like a solid white block of mycelium. 

9. Inoculate your bulk substrate

Once your grain is fully colonized, it is time to add it to your bulk substrate. This is the growing medium on which the mycelium will eventually produce mushrooms. The best substrate to use depends on the mushroom variety. Some prefer coco coir, while others favor straw or wood pellets. You could also choose to add some extra nutrients at this stage to increase your yield. 

Before you inoculate the substrate, you will need to pasteurize it. This is similar to the sterilization process described in step 6. However, it is a little quicker since the mycelium has already developed some resistance to contaminants by now and does not require full sterilization.

Pasteurization involves heating the substrate at 150–180oF for around two hours. You can do this by placing it in a large pan of water on the stovetop. We recommend placing the substrate inside a fabric bag or an old pillowcase to make it easier to remove from the water and drain.

Boil the water, then reduce the heat slightly to a simmer. If possible, use a cooking thermometer to monitor the temperature. The idea is to pasteurize the substrate rather than sterilize it. This allows beneficial bacteria to remain in the substrate while destroying potentially harmful contaminants.

If you are growing your mushrooms in a plastic tub, disinfect it with isopropyl alcohol. It is also helpful to line the base with a piece of thin plastic, such as a garbage bag, to prevent side pins, which can be challenging to harvest.

Once the substrate is pasteurized and cooled, squeeze out the excess water and add it to your box or grow bags. Crumble in the inoculated grains and mix them evenly through the substrate. Depending on the variety, you may wish to add a thin casing layer of the substrate on top.

Finally, seal the container. This will allow humidity to accumulate inside while the mycelium colonizes the bulk substrate ready for fruiting. 

Make a note of the date. 

10. Incubate your bulk substrate

This is the final incubation stage, and it should be the fastest. Depending on the mushroom variety, the mycelium could colonize the substrate in as little as 1–2 weeks. Once the substrate has become white and fluffy throughout, you’re ready to initiate fruiting.

11. Trigger fruiting 

Fruiting conditions can be significantly different from colonization conditions, and you will need to research the variety you are growing to learn their preferences. However, all fungi need fresh air and humidity to produce mushrooms. Therefore, you will need to open the container and mist it at regular intervals. It is best to mist the inside of the container or fruiting chamber rather than the mycelium itself to prevent it from getting too soggy.

You should also introduce some ambient light at this stage. This will tell the mushrooms which direction to grow and stop them from becoming spindly.

After a few days, your first pins should start to form. You will then have the excitement of watching your mushrooms develop and finally enjoying the fruits of your labor!

Growing Mushrooms: Final Thoughts

We hope you found our beginner’s guide to growing mushrooms useful and that you feel inspired to embark upon your own mushroom-growing journey. Please remember that it is a basic overview, and the stages may differ slightly depending on your chosen mushroom variety and technique. We encourage you to conduct your own research into each stage to ensure that you get an optimal harvest.

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Published on: January 17, 2024
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