Coco Coir Mushroom Substrate: How to Grow Mushrooms on Coco Coir

The empty husk of the coconut is the waste product of the coconut industry, processed into coco coir, a substrate with multiple uses that has been increasing in popularity recently.

And before all to start, yes, you can use coco coir to grow mushrooms. It is one of the best to choose from, and let’s dig deeper.

Coco Coir Mushroom Substrate: How to Grow Mushrooms on Coco Coir

How do mushrooms grow?

Unlike others, one can’t simply “plant” mushrooms just like other crops. If a farmer wants to start making profits from this cultivation, there is a need to invest in the habitat that the fungi will be growing in. Mushrooms grow from fungal spores that thrive in damp, dark conditions. They require a medium that is high in decaying plant matter.

To create this “habitat”, one crucial part of it is recreating the “high in decaying plant matter” environment, or from now called Mushroom Substrate.

Coco coir mushroom substrate recipe 

Soil and perlite with coco coir as part of the recipe to mushroom substrate:

Soi and coco coir are usually used for plants. With that, it’s also not recommended to use this substrate for mushrooms.

Perlite shares the same path. But while normally you don’t use perlite in the substrate for the mushroom itself, they play the role of keeping up the humidity level in bigger scale farms.

Pasteurization of coco coir:

Although coco coir is naturally resistant to bacteria, it’s still organic material and contains nutrients that attract pathogens. So yes, to be safe, they should be pasteurized so that there is no other organism competing with the mushroom in terms of nutrients.

Coco Coir as Mushroom Substrate


3 Steps to make Coco coir growing mushrooms

Step 1: Get what needed:


  • A container with a lid.
  • A big pot to boil water
  • Measuring cup
  • A clean stirring tool


  • 650g of compacted coco coir (brick)
  • Fine Vermiculite
  • Optional Gypsum
  • Water

A standard brick of dried coco coir weighs around 1.43 pounds (650 grams) and expands five to seven times in volume when you add water.

Ensuring Proper Watering for Optimal Expansion

The ratio is of the following:

  • 1 brick of 650g of dried coco coir
  • 8 cups of dry vermiculite
  • 16 cups of boiling water (optional 1 cup of gypsum, with additional water)

After the process, this should give a substrate that has the correct moisture content.

Step 2: Boil and prepare:

  • Add 16 cups of water into the boiler, aim to get them to about 65 or more Celsius degree and left in 6 mins to pasteurize,
  • While the water is boiling, place all the other ingredients into the bucket. 1 brick of dry coco coir and 8 cups of dry vermiculite (and gypsum)

Step 3: Pour and stir:

  • The next step is just one of the many ways to do this. Make adjustments accordingly.
  • Pour the water into the bucket and close the lid for 1 hour. This is to rehydrate the coco coir brick to the state that its able to be mixed fully with vermiculite. Use the mixing tool to stir the mixture fully.
  • Close the lid and let it cool down for about 6 to 8 hours.

To evaluate the substrate:

  • The substrate should be at field capacity, which means that when you squeeze a handful, it should hold together and only release a few drops of water.
  • If too much water comes out, it’s too wet. If no water comes out and the substrate isn’t staying together in your hand, it’s too dry.
  • When well mixed and cooled to room temperature, your coco coir vermiculite substrate is ready to use.

How to grow mushrooms on coco coir substrate

Step 1: Gather Supplies

To grow mushrooms on coco coir, you’ll need:

  • Mushroom grain spawn – It is recommended to purchase mushroom grain spawn from a reputable local supplier.
  • Prepared coco coir substrate – As following steps from the prior sector.

Containers or grow bags – You can use your bulk coco coir substrate to grow mushrooms in bags, buckets or other suitable containers.

Step 2: Inoculation

  • Inoculation is the name given to the process of adding mushroom spawn to your prepared coco coir substrate.
  • Before starting, wipe clean all work surfaces and clean your hands as well with soap to avoid contamination.
  • Also, ensure your substrate has cooled down enough as high temperatures could kill the mushroom mycelium.

 How to Grow Mushrooms on Coco Coir Substrate

How Do You Inoculate Coco Coir?

You can inoculate your coco coir substrate in the bucket you used for pasteurization or move it into a clean tote where it may be easier to mix the spawn into the substrate.

When the spawn and substrate are evenly mixed, transfer the inoculated substrate to your grow bags or containers.

If you’re using a monotub fruiting chamber, you can place the prepared coco coir substrate in the monotub and inoculate it in the tub.

You’ll need to add mushroom spawn at a minimum of 20% spawn rate to wet coco coir vermiculite substrate.

And growers recommend a spawn rate of 50% when using a plain coco coir substrate to speed up colonization.

Mix in the spawn through the substrate as evenly as possible.

Unevenly distributed spawn may result in slower colonization and increase the chances of contamination.

Step 3: Incubation

This step involves putting the bags or containers of inoculated coco coir substrate in a warm dark area at around 65 – 77°F (18 – 25°C) and leaving them to incubate.

  • The mushroom mycelium will spread from the grain spawn and grow through the coco coir substrate, feeding on the organic material.
  • The name given to this process is colonization.
  • How long the mushroom mycelium takes to colonize the substrate varies from species to species.
  • The colonization speed is also affected by the spawn rate used and incubation temperatures.
  • When the mycelium has spread throughout the substrate and completely covered the surface, it’s time to place it in fruiting conditions.

Step 4: Fruiting

  • This stage is the most exciting part of the process as you finally get to watch your mushrooms grow.
  • To encourage fruiting, you need to replicate the ideal fruiting conditions for the mushroom species you’re growing.
  • Light, humidity, airflow and temperature play an important role in this.
  • Depending on the type of mushrooms and where you live, you could create fruiting conditions on a kitchen counter or windowsill.
  • But for those in hotter, dryer areas, a greenhouse, monotub, shotgun fruiting chamber or Martha grow tent will all help to create ideal fruiting conditions.
  • Once in fruiting conditions, it won’t be long before you see mushroom pins forming on the colonized coco coir substrate.

Pros and cons of using coco coir mushroom substrate

Advantages of using coco coir substrate 

Coconut coir as a mushroom substrate that is easy to find and use, that is also come with all the upsides of following:

  • Coconut coir is 100% organic and biodegradable and reusable, made non-toxic during the coir extraction process.
  • Has a highly moisturizing ability – this is an important benefit of using coconut coir when growing mushrooms. Because coco coir has good water-absorbing  and water-holding properties, it will retain moisture for a longer time.
  • Easy to find and use – easy to find in store, or to get as they are also easy to deliver.
  • Good disease resistance – In coco coir, it is naturally resistant to pests, bacteria, and mold, which make it easier for beginners who just got into growing mushrooms and can’t afford pasteurize because of the lack of expensive equipment.
  • Excellent aeration – Coco coir has a fine powder or fibrous texture so the porous structure of coco coir allows good air exchange, which is important for the mushroom substrate during the incubation phase.
  • To make up for the lack of most of the essential nutrients such as Potassium, Sulfur, and Phosphorus, coco coir provide traces of Magnesium, Calcium, and Nitrogen that help contribute to mushroom growth.


Disadvantages of using coco coir substrate

Each type of substrate has its own drawbacks, coconut coir also has its downsides, but if you use coco coir correctly and have treated all harmful chemicals, you can avoid the following disadvantages:

  • Residual salts in poor-quality products: The manufacturing of coco coir isn’t standardized as different brands have different methods of doing it, some neglect or half-hearted the de-salt process, it ends up with high EC levels (salts still retain high contents), which can lead to serious harm to crops. This can be prevented by carefully choosing the used product
  • Uncertainty in nutrients: To some mushrooms, the coco coir already has enough of what they need. But in other cases of more picky mushrooms, if the nutrients are not provided in time, it could lead to more unfortunate endings.
  • Possible chemical residues – During processing, some manufacturers use chemicals and thereby retain chemical residues that can affect fungal growth. Therefore, you need to treat the coir thoroughly or find a source of quality pasteurized coir before starting to grow.
  • Product quality varies – Not all commercially processed coir is the same, in each facility, the manufacturer will have different processes and in some cases, the processing will destroy some natural elements.

Coco Coir Block/Brick 5kg



It is important to know what type of mushroom you are about to grow, as there could be a lot to prepare just from the type chosen.

While coco coir is readily available and inexpensive, it is advisable to choose carefully. Also, each type of mushroom has its “best”, researching before growing could prevent deficiencies in quality and other of such.

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