Urban Biosphere: Mushroom cultivation sector

BIOSPHERE EXPERIENCE

https://wiki.lowtechlab.org/wiki/Biosph%C3%A8re_Urbaine_:_Fili%C3%A8re_culture_de_champignons/en

Dernière modification le 04/10/2025

Difficulty

Easy Easy

Duration

4 hour(s) hour(s)

Cost

50 EUR (€)

Description

This tutorial was created as part of the low-tech urban lifestyle experiment conducted by Biosphère Expérience in Boulogne Billancourt. It presents the steps involved in making the mushroom towers used by Corentin, Caroline, Virginie and Laurine during the experiment, as well as the stages of cultivation from inoculation to the fruiting of oyster mushrooms.

Summary

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Introduction

The project - Urban Biosphere

For four months, Corentin and Caroline experimented with a low-tech lifestyle in the city in collaboration with a network of local actors. The idea is to take advantage of the high population density to share knowledge, divide up the work and pool resources. Emma set up and coordinated temporary networks made up of local organisations and citizens. A total of 14 people from the Boulogne Billancourt area took part in this experiment !

Sector - oyster mushroom cultivation

Mushrooms are delicious and nutritious, but their high cost on the market often poses a financial challenge. To solve this problem, Emma has created a temporary oyster mushroom cultivation facility that covers the entire reproduction cycle. Using straw pellets and grain mycelium produced at ChampiLab, Virginie, Laurine, Corentin and Caroline have recreated the entire oyster mushroom cultivation cycle. The idea is to pool space to create workshops for making cultivation towers, but also to store equipment and towers during the incubation phase. This tutorial aims to democratise oyster mushroom cultivation on a regional scale.

Organisation process during the experiment :

• Every 2 weeks, grain mycelium was prepared at ChampiLab (see tutorial Biosphère Urbaine - Clônage de champignons)
• Every 2 weeks, the 4 participants in the experiment met at ChampiLab to make 8 growing kits. Each person left with 2 mushroom towers to grow at home.

The aim of this experiment was to produce 1 kg of oyster mushrooms per person. To produce this quantity of oyster mushrooms, it is advisable to use 5 kg of substrate (in this case, straw). To avoid having towers that were too heavy, we decided to build 8 towers weighing 2.5 kg each, producing 500 g of oyster mushrooms each (2 towers per person).

If you would like to learn about oyster mushroom cultivation without setting up a production line, visit the participatory science tutorial dedicated to home oyster mushroom cultivation.

Materials

Production of 8 mushroom towers

This is a exhaustive list of materials. If you already have some items, we recommend buying second-hand and adapting the dimensions and sizes throughout the tutorial.

• Flexible PLA sheet (or other material depending on availability)
  • 8 x (48 x 66) cm
  • 8 x (20 x 20) cm

• 2 m of wooden battens. Here we have chosen a 24x13 cm profile
• Wooden board: 8 x (20x15) cm
• 56 Ø 5 mm screws
• Suspension for the towers (optional): 8 x 2 m of rope. The length of 2 m depends on the layout of your home

Assembly of the 8 cultivation kits

• 5.7 kg of straw pellets
• 1 45-litre box for preparing the substrate
• 28 g of slaked lime
• 14.5 litres of water
• 1.7 kg of grain mycelium
• Cotton fabric
• 1 bottle of 90° alcohol
• Clay balls

Tools

This is an exhaustive list of tools to be adapted based on what you already have.

• A pair of scissors
• Stapler
• Soldering iron or nail (see step 4)
• Hand saw or jigsaw
• Tape measure
• Drill/screwdriver
• Wood drill bits: Ø 3 mm; Ø 8 mm
• DIY gloves
• Safety goggles
• Face mask
• Hygienic gloves
  

Step 1 - Set up the production

If you wish to set up this type of production, you will need to find a shared space in the area and neighbours who are keen to participate in the project. Of course, I encourage you to adapt this sector to suit your needs and the organisation that works best for you.

How to find a shared space ?

I needed to find a place with several spaces: a laboratory, a storage room, and a workshop space. While exploring the area, I looked for existing places such as a biolab (a collaborative laboratory for exploring living organisms) or spaces in the city. In our case, there is no Biolab in Boulogne Billancourt, which led me to discuss with the city to find the right space: the Maison de la Planète.

How to find people to set up a production line?"

For my part, I widely disseminated the information via the city's networks (website, article in the city newspaper), our social networks, and local associations, contacting them by email and telephone. Some examples of associations: Shifters, Transition Town, Low-tech Lab, etc.

More generally, I talked about the project to everyone I met on a daily basis. If you want to talk about it to your family, friends, and colleagues, I invite you to use all the documentation in this tutorial to help you feel confident in presenting the objectives and benefits of setting up such a sector on a regional scale.

In addition, 250 citizens in France and abroad have experimented with growing oyster mushrooms as part of the participatory science program. Feel free to join the WhatsApp groups set up during the experiment! You may find people near you who are interested in setting up this sector.

Step 2 - Purchasing equipment

Depending on the setup you choose and how you reuse materials, we estimate that it will cost between €10 and €50 to grow mushrooms. This depends on the materials used, where you get your grain mycelium (homemade or purchased from a supplier), etc.

Before making your purchases, we strongly recommend that you read the entire tutorial. We encourage you to make group purchases to avoid waste and share any delivery costs.

Step 3 - The following steps concern the fabrication of the 8 mushroom towers.

If you want to learn how to make grow kits, go to step 7 !

Step 4 - Cutting materials

As a reminder, this tutorial shows you how to make 8 mushroom towers. Adjust the instructions according to the number you wish to make. Each tower requires 2 wooden frames.

Wooden frame

• Using a hand saw (or jigsaw), cut 28 pieces of wood batten measuring 13 cm in length (1)
• Using a hand saw (or jigsaw), cut 28 pieces of wood batten measuring 15 cm in length (2)
• Make 14 frames by assembling 2 pieces of wood (1) and 2 pieces of wood (2). For a neat finish, pre-drill holes using a 3 mm drill bit, then assemble with 5 mm screws
• Optional: on all the frames, drill two ⌀8 mm holes in two opposite battens (see photo 1). This will allow the rope to pass through if you want to hang your towers during fruiting (see step 5). The diameter of the holes depends on the diameter of your rope

PLA

• After drawing 8 rectangles measuring 48 x 66 cm and 8 squares measuring 20 x 20 cm on your flexible PLA sheet, cut them out with scissors

Wooden board

• Cut 8 pieces of wood measuring 20x15 cm. These will support the weight of the towers
  

Step 5 - Fabrication of the 8 mushroom towers

1 tower

• Position one end of a 48 x 66 cm piece of PLA inside one frame and staple it in place. It is perfectly normal for the PLA to overlap
• Position the other end of the PLA inside the second frame and staple it in place.
• Staple a 20 x 20 cm square of PLA to the second frame
• Attach a 20 x 15 cm wooden board to the second frame (this will support the weight of the tower). For a neat finish, pre-drill holes using a 3 mm drill bit, then assemble with 5 mm screws

8 towers

• Repeat these steps to make the 8 mushroom towers

Step 6 - Finishing touches

The mushrooms will need to find a way to grow outside the tower. To do this, we will make holes in the PLA to facilitate the development of oyster mushrooms.

1 tower

• Make holes approximately 5 mm in diameter in the PLA walls using a soldering iron (see photo 1) or a heated nail (see photo 2). You can space them about 10 cm apart

After making a hole where two pieces of PLA meet, press them together to stick them (see photo 3)

• Optional: in the same way, make 2 holes in the PLA square, at the level of the holes in the lower frame, to allow the rope to pass through (see step 5)

8 towers

• Repeat these steps to make the 8 mushroom towers

Step 7 - Tower attachment system (optional)

This step is for those who wish to suspend their mushroom cultivation during the fruiting phase (at home).

• Pass the rope through one of the holes in the upper frame, then through the hole in the lower frame (see photo 1). Tie a knot at this end (see photo 2).
• The rope then passes through the other two holes in the upper and lower frames. Tie a knot at this end (see photo 3).

Step 8 - The following steps concern the preparation of the cultivation kits

Where to find the inputs?

Straw pellets

Be sure to use organic straw pellets that are free of fungicides. For this experiment, we used 20-liter bags of straw pellets. You can find them at mushroom growing supply stores or pet stores.

Slaked lime (or lime putty)

It allows you to pasteurize the substrate to prevent contamination (see step 8) and can be easily found in DIY stores (€10 for 4 kg, Bricorama)

Mycelium grains

As part of this experiment, we recreated the entire oyster mushroom cycle. Find the tutorial to discover how we made the grain mycelium here: Grain mycelium at ChampiLab. If you don't want to make it yourself, you can buy it from a supplier such as Breizh Bell (Brittany) or La Mycosphère (Belgium).

Step 9 - Preparing the workspace

Before starting, it is important to thoroughly disinfect all equipment used to prevent contamination.

• Wear gloves and a mask
• Clean work surfaces, the substrate preparation tray, and all containers and equipment you use with a cloth soaked in 90° alcohol

Step 10 - Pasteurization and rehydration of straw pellets

Pasteurizing straw pellets prevents contamination in the substrate. Several techniques exist, but here we have chosen to test lime pasteurization . This process involves adding slaked lime to the straw pellets in order to destroy pathogenic germs. Slaked lime is used in particular to increase the pH of the straw, creating an environment that is less conducive to the development of bacteria or mold but more conducive to the development of oyster mushroom mycelium. The straw pellets then need to be rehydrated to create an environment conducive to mushroom growth.

This step requires wearing a type 2R mask to avoid inhaling fine particles. Avoid touching the lime or straw pellets during handling.

For the rehydration stage of straw pellets, you need to achieve approximately 60% moisture content (no water should drip when you squeeze the straw). Here, we use 2.5 L of cold water per kilogram of straw pellets to be rehydrated, but this depends on the quality and size of your straw pellets. I recommend conducting several tests to find the ratio that works best for you.

For pasteurization, it is recommended to use one cup of slaked lime (approximately 80 g) for 50 L of cold water. Here we use 14.5 L of cold water for 5.7 kg of straw pellets, which means 23 g of slaked lime.

As a reminder, the quantities indicated are sufficient to make 8 oyster mushroom growing kits. Adjust the quantities according to the number of kits you wish to make :

• Pour 5.7 kg of straw pellets into the substrate preparation tray
• Pour 23 g of slaked lime into the substrate preparation tray
• Rehydrate the straw pellets by adding 14.5 L of room temperature water to the substrate preparation tray
• Leave the straw pellets to soak in the water for at least 20 minutes to allow them to absorb the water. During this process, you can mix the contents to distribute the water evenly
• Your substrate is ready when water does not run out when you squeeze a handful of substrate

Step 11 - Preparation of the 8 mushroom towers

Similarly, it is important to thoroughly clean mushroom beds to prevent contamination.

If you reuse the towers after fruiting

• Remove the mycelium block and keep it to make mycelium objects, insulating bricks, or use it as mulch for your vegetable garden. You can also plant it in your garden: the mycelium will find new nutrients in the soil, which may encourage mushroom growth (we have never tested this technique).
• Clean the towers thoroughly with a brush and water to remove any pieces of mycelium.
• Clean the towers with a cloth soaked in 90° alcohol. Keep the square of cloth, as it will be used at the end.

If you use new towers

• Clean the mushroom stems with a cloth soaked in 90° alcohol. Keep the square of cloth, as it will be used at the end.

Step 12 - Inoculation of the 8 mushroom towers

Inoculation consists of introducing the mycelium in grains into its culture medium, in this case straw pellets.

• Use a pair of scissors disinfected with 90° alcohol to open the bag of grain mycelium. Find instructions for purchasing or making grain mycelium in step 5 of the tutorial
• Carefully break the block of grain mycelium through its bag (see photo 1).
• Fill your towers in layers: a layer of substrate, a layer of mycelium, a layer of substrate, a layer of mycelium, and so on, finishing with a layer of straw pellets (see photo 2). Ideally, one person should be in charge of distributing the mycelium while the others fill the towers with substrate. We recommend that you continue to wear your mask during this step to avoid contamination.

As a reminder, do not touch the mycelium grains or straw pellets to avoid contamination

• Press down lightly to remove air pockets (be careful, if pressed too hard it may rot).
• Cover the top of the towers to retain moisture and prevent the introduction of contaminants:
  • Clay balls (see photo 4)
  • A piece of alcohol-soaked cloth used to disinfect the towers (see photo 5). Be careful, as fungi may break it down.
  • A piece of PLA or used coffee grounds (we have never tested these techniques).

This culture may attract a few gnats

• Don't forget to date your turns to make tracking easier (see photo 6)!

Step 13 - Incubation of the 8 mushroom towers

Incubation, also known as colonization, is the period during which the mycelium grows and stores as much food as possible in preparation for the development of the mushroom.

Strict conditions must be met to promote proper colonization of the substrate:

• darkness
• stable temperature (day/night): minimum 20°C for oyster mushrooms (varies depending on species)

Here, we place the 8 mushroom towers in a room in the ChampiLab. We recommend placing a thermometer in the room to check the temperature every day. The incubation period lasts about 2 weeks!

The next steps are to be carried out once the mycelium has colonized the towers (white areas inside, see photo 2)

Step 14 - Fruiting

At this stage, the straw in your kit should be colonized by mycelium (several white areas in your kit, see photo 1). If this is not the case, wait a few more days.

How can you ensure successful fruiting? In the forest, the mycelium lives under the bark in the shade; in autumn, when it starts to rain and the temperature drops, this causes stress, which prompts it to fruit so that it can reproduce. The four main environmental factors to control during fruiting initiation are: humidity, aeration, temperature and light.

• Once the mycelium has colonised the straw (several white areas in the tower), collect your mushroom towers from ChampiLab and place them in your home in a place that is:
  • bright (without direct light on the bag) such as your shower, bathroom or kitchen
  • well ventilated

Please note that liquid may leak from your towers! We recommend placing a container under your towers (if there is too much water)

We recommend placing your towers in your shower! This way, you won't need to add water to grow your mushrooms: they will benefit from the ambient humidity and water droplets to develop

If you place your towers in your shower

• You do not need to spray them with water: the growing tower uses ambient humidity to thrive.

If you place your towers in a different place

• Spray the tower (around the holes) approximately twice a day using a spray bottle that has been disinfected beforehand. It is advisable to use water that has been boiled beforehand to avoid contamination.

Advice in case of problems during fruiting

• Contamination (see photo 3): put tape over the holes in the contaminated area and it is possible that mushrooms will grow on the uncontaminated areas. If the contamination is widespread, it is best to throw everything away.

It is not dangerous as long as the mould is not on the mushroom or nearby

• Too much water (see photo 4): Place it in a warm or less humid place.

Step 15 - Oyster mushrooms harvest

As soon as primordia (oyster mushroom buds) form, they double in size every day. Under the right conditions, the oyster mushrooms will start to grow through the holes after 2-3 weeks!

Harvest oyster mushrooms before the caps open up and release too many spores.

• To do this, gently turn the cluster with your hand, all at once. Be careful, they grow quickly! If you harvest them a little late, it's not a big deal, but they may be a little less flavourful and tender (and spread spores).

Under good conditions, you can get 2 to 3 harvests (depending on the strength and quality of the mycelium). With one tower, you can expect to harvest around 500 g of oyster mushrooms!

• When your tower no longer produces oyster mushrooms, go to step 8 (to be reviewed) to build a new growing tower!

Step 16 - Recipe ideas

Shredded oyster mushrooms (serves 4)

Ingredients

• 500g oyster mushrooms
• 2 onions
• 3 tablespoons olive oil
• 2 tablespoons salted soy sauce
• 1 tablespoon agave syrup
• 2 tablespoons water
• smoked paprika
• garlic powder
• herbes de Provence or spice mix of your choice

Instructions

1. Preheat the oven to 190°C.
2. If necessary, clean the oyster mushrooms with a brush or a slightly damp cloth. Do not rinse them under water.
3. Then break them lengthwise to obtain thin strips
4. Slice the onions into rings
5. Marinade: in an ovenproof dish, mix the oil, soy sauce, agave syrup, crushed garlic cloves and all the spices
6. Add the oyster mushrooms and onions to the dish. Mix everything together to distribute the marinade evenly.
7. Bake for 25 minutes, stirring halfway through cooking.
8. Crispy on the outside and tender on the inside, all that's left to do is enjoy!

Spaghetti with oyster mushrooms (serves 2)

Ingredients

• 300 g oyster mushrooms
• 140 g spaghetti
• 1 onion
• 1 clove of garlic
• 25 cl vegetable cream
• 1 tablespoon brewer's yeast
• salt, pepper
• optional: white wine

Instructions

1. Brown the chopped onion and garlic clove in a frying pan with a dash of oil.
2. If necessary, clean the oyster mushrooms with a brush or a slightly damp cloth. Do not rinse them under water.
3. Tear the 300g of oyster mushrooms into the pan
4. When browned, add the 25cl of vegetable cream, salt and pepper. You can add a little white wine, but this is not essential. Reduce to a low heat and cover for a few minutes
5. Meanwhile, cook the 200g of spaghetti.
6. At the last minute, mix the spaghetti with the oyster mushroom sauce in the pan with 2 tablespoons of brewer's yeast. It's delicious!
7. Serve on attractive plates and add pepper and brewer's yeast on top.

Giant oyster mushroom for wraps (depending on the cluster harvested: serves 2–3 people)

Ingredients

• wrap bread
• a nice bunch of oyster mushrooms
• 2 tablespoons olive oil
• 1 tablespoon soy sauce
• 1 teaspoon garlic powder
• 1 teaspoon smoked paprika
• salt, pepper
• side dish: fresh vegetable salad and brewer's yeast

Instructions

1. The marinade: mix the olive oil, soy sauce and various spices. Set aside
2. If necessary, clean the oyster mushrooms with a brush or a slightly damp cloth. Do not rinse them under water
3. Cook the oyster mushroom cluster for 1 to 2 minutes over high heat in a frying pan with a drizzle of olive oil to brown on each side.
4. Lower the heat and flatten the cluster with a heavy weight on top (ideally, press down with a saucepan).
5. Turn off the heat and brush the cluster with marinade.
6. Bake for about 15 minutes at 180 degrees to get a crispy skin without burning it.
7. Make your wrap with pieces of oyster mushrooms, fresh vegetables and brewer's yeast.

Oyster mushroom wings (serves 2)

Ingredients

• 100 g oyster mushrooms
• 100 g flour
• 100 g wheat semolina
• 1 teaspoon onion powder
• 1 teaspoon garlic powder
• 1 teaspoon paprika
• herbes de Provence
• neutral oil for frying
• side dish: fresh vegetable salad and brewer's yeast

Instructions

1. Breading mixture: mix the flour with the herbs and spices, then add the water.
2. If necessary, clean the oyster mushrooms with a brush or a slightly damp cloth. Do not rinse them under water.
3. Pour 4-5 cm of oil into a small saucepan and heat to 180°C.
4. Dip the oyster mushroom pieces in the breadcrumb mixture, then in the semolina.
5. Place in the deep fryer and fry until golden brown. Stir with a slotted spoon halfway through cooking.
6. Remove from the oil with a slotted spoon and place on a rack set over a baking tray or platter to allow the excess oil to drain off, or on a tray lined with kitchen paper or a tea towel reserved for this purpose (wash thoroughly with soap and water before putting it in the wash).
7. Fry all the oyster mushrooms in the same way
8. Enjoy the oyster mushroom wings with a lovely seasonal salad!

Notes and references

Document written by Emma Bousquet-Pasturel as part of the Urban Biosphere experiment at Biosphère Expérience. Many thanks to Pierre Bonnet from Breizh Bell for proofreading the document.

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