Frequently Asked Questions


What is mycelium?

Check out our blog post to learn more.

Is mycelium safe to use?

Mycelium is safe to use. It is mainly composed of natural polymers as chitin, cellulose, proteins, etc, so it is a natural polymeric composite fibrous material. But we definitely do not recommend eating the substrate.

Is mycelium waterproof?

No, the material will lose rigidity and will become susceptible to degradation when repeatedly exposing it to water. It does repulse water for some time and it even floats! Of course, it not raining all the time. In between showers the material will passively dry and maintain some rigidity. But in the long run, it will lose.

We are working on the development of a bio-based coating that makes our material 100% waterproof.

After the Mycelium has been baked, will it biodegrade safely when left outside?

Yes, it will biodegrade. But there is something you need to know about it: biodegradation takes place under influence of outdoor conditions, and these conditions can differ from location to location. It is probably easy to understand that a product will biodegrade easier in a hot, humid, and tropic environment than on the north (or south) pole. Also, the size of the product is important: crumbling your mycelium product will speed up the biodegradation. There is more: biodegradation is quicker when there is oxygen. So, in a marine environment like the sea, underwater, biodegradation is even more difficult. But we are happy to tell you that Mushroom ® Packaging is also marine compostable.

What about watering a plant in mycelium pots, how does the humidity affect the pot since it is biodegradable?

It’s a smart idea to have an extra internal pot to catch the water because mycelium pots are biodegradable and constant(long term, more than 5 days) contact with water will result in the pot wall and bottom slowly absorbing the water, making the pot squashy, but also attracting external molds.
I have several mycelium plant pots at home (with an internal pot) and they’ve been lasting for a long time already.


Can mycelium be stored in wet areas?

It is better not to store mycelium in wet areas, because when the mycelium gets wet it will lose its strength. So, the material itself should be kept dry. Furthermore, other fungi might exist in wet areas which consider mycelium as nutrition. One way to protect it is by using a coating. On demand only, offers the coating of product for its customers

How can I change colour of mycelium?

There are two ways: use a biobased paint or a milk paint. We recommend using a milk paint. If you want the mycelium to do the work, you just need more time. That is a tricky process because growing the substrate too long means that you may see mushrooms coming out, which will weaken the base structure. We usually extend by one week to create darker, greyish but sometimes also brown or orange colours.

So, how long does the final mycelium material last?

The durability of the product strongly depends on its surrounding environment. If you keep it indoors, in a climate typical for Europe (north as well as south), it will remain intact for a lifetime. However, if the product is in constant contact with soil or wate outdoors, it will gradually starts to degrade. Additionally, high humidity could speed up the process.

I want to use my mycelium cool box to keep my food cooled. But are your materials suitable for food or beverage containers?

Our materials are not certified for direct food contact. The materials are water permeable and are not recommended for applications such as disposable cups.

MycoComposite ™

What exactly is MycoComposite ™?

Our material is made of mycelium, which is the root structure of fungi, combined with organic agricultural waste. In our case that’s hemp fibres. The hemp is industrial hemp, used for fashion, and we get the waste fibres.  After bake-off, mycelium is chemically the same as Chitin. More Info:

What are the properties of your MycoComposite™?

We have summarized the properties in a spec sheet for you. Click here to download the specifications sheet.

How does the production look like?

Our production process begins by mixing the mycelium with hemp fibres. Once combined, we fill specific growth forms and let the product grow for several days. Afterwards we place it in bog ovens. This step ensures that the mycelium stops growing. You can find all the steps also here in our youtube video:


I want to experiment with my product once I received it. How can I adapt my products post-production ?

The possibilities are endless! You can for example cut the material with a saw, drill holes in it or cover it in laminated wood. We recommend natural, biobased sealants as the purpose of the material is to not add toxins to the environment. The material can be sanded and finished with beeswax, milk paint, water-based polyurethane, and more.

I am looking for a sustainable packaging alternative for my product. Is my business product suitable for MycoComposite™?

Every case is different, but we are happy to explore possible packaging solutions for your product. Reach out to use and we can discuss how suitable your product is. 

At GROWN bio, we focus upon sustainable packaging solutions for people that are looking for circular alternatives. We grow packaging for bottles, electronics, cosmetic products or any other shape that needs to be packed. Check out this page to find out more about mycelium packaging!   

Mushroom® Packaging

How do I learn more about Mushroom® Packaging?

Follow us on Facebook, Instagram, Twitter or LinkedIn for our latest developments and research! Are you curious about the possibilities for Mushroom® Packaging for your own product? Have a look at this page about our packaging solutions.

Why is mycelium the ultimate packaging solution?

Learn more about that here.

How long does it takes to compost mycelium packaging?

Composting is a process that is executed by nature. The temperature, wind, soil activity, rain, all play a role in that process. Plus, the size of the to-be composted product.

Here an example from The Netherlands:

  • If you keep a compostable mycelium packaging in your house, it will stay good forever, if your house is dry and well ventilated
  • Throwing a compostable packaging in nature outdoors:
    • Will take several (>5)  months in winter
    • Will take several weeks (> 5) in summer (more soil activity, and here in NL we have frequent rain)
    • Will take several weeks (>weeks) in winter when you break the packaging in small pieces
    • Will take until 4 weeks in summer when you break the packaging in small pieces
  • Throwing a compostable packaging in water is perfectly OK, it does no harm. But the composting takes longer because of the lack of oxygen that speeds up the composting.

What can you pack in mycelium?

From glass bottles, radiators, watches, ventilators, cosmetics to candles, we can almost pack anything. Learn more about that here.

Is mycelium packaging CO2 neutral?

For an in-depth answer, I’d recommend visiting our landing page: Obviously, the CO2 negativity (or positivity) is depending on the distance the mycelium packaging is shipped.

Disposal or recycling instructions for mycelium packaging?

You can simply break it into small pieces and return it to mother earth. It will naturally degrade without leaving any harmful residues.

Is there any cost comparison between mycelium packaging and traditional packaging materials?

Mycelium packaging is currently still more expensive than plastic foams. The main reason is that the current production processes for mycelium products are not yet fully automatic, while other materials in the packaging industry are made at large scale. By doubling the production in the last years. Mycelium products have already reduced by a factor 50%, and further improvements are made month by month.

But it’s incomparable when it comes to the price it takes on the well-being of our planet and our health. 😉

How strong is Mushroom® Packaging?

Watch this:

Can you pack food in mycelium based products?

Mushroom® Packaging is not tested for direct food contact, so it can not be used to pack food if it is directly in touch with the myclieum. Prepacked food can be packed in Mushroom® Packaging.

Can you pack cosmetic articles in mycelium?

Yes! Learn more about it here.
We offer packaging solutions for cosmetics that align with the values of the industry. Sustainability is at the core of everything we do, from our products and packaging to our entire supply chain. 
Mushroom® Packaging is the perfect solution for your product.

Is Mushroom Packaging compostable?

Yes! Our packaging is fully home and marine compostable due to its organic composition.

What are the primary environmental benefits of mycelium packaging compared to traditional packaging materials?

Mycelium packaging stands out as a clear winner when compared to traditional packaging materials, especially when considering its environmental benefits. Made from organic materials, it’s entirely biodegradable, meaning it naturally breaks down without leaving lasting pollution. The production uses just two main ingredients: mycelium, the root structure of fungi and local agricultural waste, ensuring that the packaging is truly sustainable. 
In our case, the local waste is hemp, a plant known for its remarkable ability to capture large amounts of CO2. 

In comparison to plastic foams, the environmental advantages are very big: by replacing Styrofoam (EPS) with mycelium packaging, fossil sources are saved – the stay in the earth – while in organic waste fibres that would normally be incinerated or composted, get a second life. That is more local and less CO2 intensive:

Moreover, unlike paper packaging which often leads to deforestation, mycelium packaging involves no tree cutting. This means we’re not just avoiding harm to our forests, but we’re actively using a material that benefits the planet when it goes back to nature. The entire process showcases a commitment to a more sustainable and harmonious relationship with our environment.

Are there any potential allergenic concerns or health considerations related to mycelium-based packaging?

No, there are no allergenic concerns or health considerations known.

How strong is Mushroom® Packaging?

Check out this YouTube Video:

Is Mushroom® Packaging scratch proof?

Check out our Sratch Test:

Grow It Yourself Kit

How should I get started with my GIY Kit ?

We have created an instruction video for you as well as an instruction manual for the Grow-It-Yourself Kit and an instruction manual for the GIY Packaging Kit. Do you still have doubts or questions after looking at the instructions and FAQ’s? Don’t hesitate to contact us!

I received my substrate, but how should I store it?

Mycelium grows in ambient temperatures. Before using the substrate, you want to slow down the growing process. Place the substrate in the refrigerator (1 – 7°C) and best use it within five days. Don’t place your substrate in the freezer.

Ooh No! I wasn’t able to use my GIY substrate within five days, do I need to throw it away ?

No, you don’t have to – as long as you haven’t opened the bag yet! We encourage you to do a little experiment and still use your substrate. If it’s very difficult to break up the substrate in small particles, it might be that the mycelium already started doing its job by gluing the particles together. Don’t worry, just add a little bit of water to prepare it for production.

Once I opened the bag, how much time do I have to use the mycelium?

The GIY kit must be used immediately after opening.

My Grow-It-Yourself Kit is based on hemp waste. But hemp, isn’t that the stuff that contains the drug THC?

The answer is unequivocally NO… Some of you might feel sorry about that 🙂 But the hemp waste we use, is industrial hemp that does not contain THC. The only organism that grows in the kit is the mycelium.

What is sculpting mix?

This helps to make the GIY material a little bit more sticky. For example, if we fill the mould of a Mush Lume, we use the sculpting mix so that the substrate does not fall down when it is close to the top of the mould, where it is very steep/vertical.

How to use the sculpting mix?

1. Loosen your GIY substrate in a sterile environment

2. Add 30 g, measure precisely, for every kg substrate used ( 1kg substrate = 3L).

3. Add the sculpting mix

4. Mix thoroughly

5. Put the substrate in the shape you want

The sculpting mix has to be added when working the substrate, not after drying.

For more detailed instructions, check our instruction manual.

How can I create that nice soft skin?

You can do that by taking the shape out of the mould after 4 days, and placing it in a closed environment to grow 2 more days.

How thin or thick should my product be?

Make sure that the walls of your product are at least 1,5 cm and that the total thickness is not more than 10 cm.

Can I add other substances (eg. new substrates, odours, colours)?

Yes, you can. However, we cannot guarantee it will work. Make sure you work sterile, and do not mix the added substrate too much.

I am not quite sure where to place my mycelium during the growing phase. Does the mycelium need to grow in the dark?

No, this is not required. Mycelium grows just fine in a dark place, and some daylight does not matter. Do not place the mycelium in direct sunlight, this will heat the substrate and it could dry out faster.

Can mushrooms grow out of the substrate? This seems like a nice extra feature for my product?

It’s possible but it’ll weaken the structure of your product. If this is not an issue for the purpose you have in mind for your product, feel free to experiment and extend the growing period. When the substrate starts to turn brown-ish, it means mushrooms are on their way!

Please keep in mind that if you need your product to be strong, you have to stop the growing process in time.

If I had a piece of wood in the substrate to fix the part of to the wall, should I add something else (eg. glue or resin)?

When adding wood in the middle of your substrate, it is not necessary to add glue or resin. The mycelium will bind naturally to the wood, which you can attach to the wall afterwards.

Consider the weight of the mycelium composite. If it is too heavy and the wood too small, it might break.

As it is an ever-expanding living thing, I assume one pack would be enough to grow into any space?

It does not increase in size.

Can I prevent or stop contamination?

If you see a green/blue-ish spot, you have spotted contamination. If you’ve spotted this in your still closed GIY substrate, contact us.

Contamination can also occur after you’ve filled your mould or while drying. First, make sure to work sterile. Contamination can occur while filling your mould due to your working surface/hands/mould not being clean enough. Second, a few precautions can be taken to prevent contamination during the drying process. Especially thicker shapes (more than 2.5cm) and products that have been taken out of the mould but are still alive/wet are susceptible to contamination. See below for the guidelines we recommend for drying:

  • For products with a thickness > 2.5 cm:
    Place the product in the oven at +/- 40° C for 3-4 hours with the door a bit open so the moisture can escape.
    Bake off at 80°C for 2 hours.
  • For products with a thickness < 2.5 cm:
    Place the product in the oven at 80° C for 2-3 hours.

A contaminated product can be thrown away.

What is the substrate material used in the GIY Kits ?

Our GIY Kits consist of hemp and mycelium. The hemp consists of hemp waste particles of 5 to 15 mm inoculated with mycelium.

My GIY mycelium substrate arrived with some water inside of the bag. Can I still use it?

Yes! The water is a result of the drop in temperature. We keep the substrate in a very cold environment, which is not conserved during the shipping. Therefore, some water is released.

My GIY substrate is white and compact upon arrival. Can I still use it?

Yes, you can! During shipping, the mycelium is exposed to warmer temperatures and therefore starts its growth. The white is the mycelium that is doing its job. When the shipping takes longer, the mycelium will grow, and thus more white parts will be in the bag of substrate. The process even speeds up when it’s warmer outside. But in the plastic bag, the material will stay moist, and alive. 

Make sure to properly break down the substrate in small chunks to avoid air cavities when filling your mould. This will make the white colour disappear, but the mycelium will still be there! Do you want to know if it is moist enough? Make a small ball in your hand, and if it doesn’t fall apart the moist level is good. If not, add a little water.  

How long does the GIY substrate last?

You can keep the substrate refrigerated for a maximum of five days. During its storage, it loses moisture and can therefore dry out. Make sure you use it when it is still nice and ‘fresh’.

On the GIY instruction sheet, it says to use ethanol. Are there alternatives which I can use instead?

Instead of ethanol, also iso-propyl alcohol (IPA) can be used. Also, detergent, normally used for dishes, utensils, cups, etc, can be used for cleaning moulds, hands, mixing bowl, etc. Rinse thoroughly so no soap is left behind

Can I use any type of flour (eg. plain, self-raising or rice flour)?

You can use any type of flour. It just functions as a ‘kickstarter’ for the growth of the mycelium.

Can I just use my normal oven?

Yes, when baking your product, you can use your own oven.

For products with a thickness > 2.5 cm:

  • Place the product in the oven at +/- 40° C for 3-4 hours with the door a bit open so the moisture can escape.
  • Bake off at 80°C for 2 hours.

For products with a thickness < 2.5 cm:

  • Place the product in the oven at 80° C for 2-3 hours.

Is the humidity level in the room important during the growing process?

In our factory we have incubators to control the humidity level. However, when growing the mycelium yourself, just make sure you cover the mold filled with the substrate to keep the moisture of the substrate in the mold. You do not want the moisture to evaporate, or your product will dry out.

According to the instructions, I have to mix the substrate once all ingredients have been added. When is the substrate properly mixed?

Make sure to keep mixing until all flour is evenly distributed, meaning no chunks of flour in your substrate. Also, try to avoid chunks of substrate by breaking them apart in small particles with your (clean) hands or tools.

What traces would it leave in the environment?

Only hemp fibers and chitin.

Would a glazed pottery mould be suitable?

We only use recycled plastic. We are not sure, so you can give it a try. 
But check out our blog post about “Make your own growth form” for more information

Can I feed any organic matter such as food/animal waste?

The kit comes ready to use. Some people who like to experiment add all kinds of things just out of curiosity. Sometimes it works, sometimes the mycelium simply doesn’t grow on it, sometimes it attracts an external mold and contaminates. Also important, if you add other matter, don’t dilute it too much. Our advice – max 25% volume increase.

How many liters do you need per cm³?

1000cm3 is 1 liter.
However, it’s important to consider the potential shrinkage that occurs during the drying process. That is 4% horizontal and 7% vertical:
Desired shape 100*100*50mm
Mould shape 104*104*53mm (or 54…..)
Contents 104*104*53/1.000.000 = x liters

Insulation Panels

Can I hang the panels?

Yes! Make sure you have several points to attach and maybe a piece of wood attached to the panel, instead of adding screws directly into the panels. The material might still be fragile, and therefore normal screws might damage the material. Be careful and use screws with a large cap into the material.

Can I modify/saw the panels?

Yes, to a certain extent. You can cut the panels. Take into account that the cut parts will be fibrous, as this is the inside of the mycelium composite. To avoid any loss of fibres or strength, you could add a bio-based coating.

What is the heat capacity of the material?

Please see our specsheet under insulation value. Click here to download the specifications sheet.

Can I sand the panels?

No, this is not possible. Sanding the panels will result in the loss of the mycelium skin surrounding the panel.

What is the lifespan of an insulation panel?

Unlimited if kept dry in a well-ventilated space.

How long is the entire production process of a mycelium insulation board?

About 7-10 days, also please check our GIY page.

Delivery & Refunds

What countries do you ship to?

We only ship within Europe.

Do you ship to the UK?

Yes, we ship normally to the UK, which means our goods need to pass through customs clearance. In the rare case the substrate of your GIY-kit has become obsolete due to customs delay, we will give a 50% discount on the product price of your next order of similar amount.

When will my order be shipped?

All orders are sent on the next Monday. So, all orders placed and paid before Sunday 23:59 will be shipped the next Monday. This also applies for Express shipments.

What happens to my order if I am not at home during the delivery?

If you use a private address for shipping address and you’re not at home when UPS delivers, it most likely will be dropped at a UPS Access Point, so keep an eye on your email.

Can I ship my order to a country outside of the EU?

Yes, it is possible to ship your order to a non-EU country. However:

  • We apply a minimum order value of €500
  • An admin fee of €25 applies
  • We require the customer to arrange pickup and customs clearance. Most do that by simply sending us a UPS / DHL / Fedex waybill and label. Once we package your order, we will send you the dimensions you need to do this. We make sure the products are ready-packed with 3 commercial invoices.

Feel free to reach out to us for additional questions about this!

When will my order be delivered?

We cannot give a fixed delivery date. Our experience is that 90% arrives within 3-5 days and Express shipments within 1-2 days.

Will my order be shipped carbon neutral?

Yes, we ship all our orders carbon neutral via UPS.

Couldn’t find what you were looking for?

Reach out to us for your remaining questions