Understanding the life cycle of cultivated mushrooms

Before delving into the practical aspects, it is worth briefly recalling the life cycle of a fungus as grown:

• It all starts with the myceliumwhich is the vegetative apparatus of the fungus. It consists of a network of microscopic filaments (hyphae) that develop in a nutrient substrate. In culture, the initial mycelium generally comes from a parent strain isolated in the laboratory, multiplied first on agar and then on grains (mainly sterilised cereals such as millet and rye) to create the seed mycelium (also known as spawn).
• This seed mycelium is then inoculated in a substrate (straw, wood, compost, etc.), where it will colonise the space and develop. This is the incubation or colonisation. During this period, optimum conditions for vegetative growth are maintained: relatively high temperature (20-28°C most of the time), darkness or low light, high CO₂ levels (little ventilation) to encourage mycelial spread.
• Once the substrate is well colonised by the mycelium (you can see this because the entire substrate takes on a whitish colour due to the mycelium present everywhere), you trigger the fruit-bearing. This is the process by which the mushroom, sensing favourable conditions, will form primordia (mushroom outlines) and then grow them into full mushrooms. To induce fruiting bodies, we change the parameters: generally, we lower the temperature, increase the humidity of the air, ventilate to reduce CO₂, and switch on a diffused light. These changes signal to the mycelium that it is "in autumn" or "out of the ground" - conditions conducive to sporophore production.
• Then comes the harvest when the mushrooms reach the desired maturity. Depending on the species, the whole cycle from inoculation to harvest can take from a few weeks to a few months.
• After the first harvest (often called first flight The mycelium, if it still has resources in the substrate, can form mushrooms again. The substrate is therefore left to rest for a few days, and then good conditions are maintained for a new flush. second flightand possibly a third. Each flock is typically less abundant than the previous one, until the substrate runs out of nutrients or water, or is invaded by other micro-organisms.

This general cycle applies to saprophytic fungi (those we cultivate, which feed on dead organic matter). It should be noted that all cultivated mushrooms follow this pattern, but with different characteristics. significant variations between species. For example, the button mushroom (Agaricus bisporus) needs an additional 'casing' stage (a layer of soil, called casing soil, is added to the incubated compost) in order to bear fruit, whereas oyster mushrooms do not. Shiitake mushrooms, on the other hand, require a shock (sometimes a mechanical shock or a phase of drought followed by re-wetting) to trigger the formation of primordias.

Main species grown and associated substrates

Many species of mushroom are cultivated throughout the world, but they can be classified into broad categories according to the type of mushroom they contain. substrate they use and the mushroom cultivation techniques employed:

• Cultivated mushrooms (Agaricaceae) The best known is the button mushroom (Agaricus bisporus), as well as its brown version (crimini) and Portobello (a variety of button mushroom harvested when ripe). These mushrooms grow on a compost fermented with manure and straw. Mushrooms are grown in crates or long beds. The mycelium is incorporated into the compost (the "encemencement" phase), left to incubate for a few days (the "spawn run" phase), then covered with a layer of moist soil (potting compost). This layer serves to retain water and stimulate the fungus, which needs this air-soil interface to form its sporophores. After a few weeks, the first mushrooms appear on the surface of the mould. Production is spread over several waves. These mushrooms do not take well to competition from other microbes, which is why it is so important to have well-pasteurised compost and good casing.
• Exotic wood-rotting fungi : Here we find the Oyster mushrooms (Pleurotus ostreatus and others, such as grey oyster mushroom, yellow oyster mushroom, pink oyster mushroom, oyster mushroom king - eryngii), the Shiitake (Lentinula edodes), the Nameko (Pholiota nameko), the Reishi (Ganoderma lucidum, for medicinal use), the Maitaké (Grifola frondosa), etc. These fungi grow on substrates rich in cellulose and lignin - typically straw, woodor mixtures of various plants. They are often grown in bags or blocks, either on pasteurised substrate (common for oyster mushrooms on straw), or on sterilised substrate (more common for shiitake on enriched sawdust, reishi, etc.). These are the mushrooms that EUROSUBSTRAT CALLAC produces in the form of incubated substrates. Oyster mushrooms are undoubtedly the easiest and quickest to grow, while shiitake mushrooms are slower and more demanding. Most of these mushrooms do not need casing (with the exception of maitaké, where some grow with a thin protective layer). They fruit directly from the substrate block via openings in the plastic or on the exposed surface of the block.
• Other cultivated mushrooms : We can mention the Enoki (Flammulina velutipes), which grow on enriched sawdust, the Shimeji (Hypsizygus marmoreus) also on a lignocellulosic substrate, theJudas ear (Auricularia) on wood or sawdust, etc. Each has its own specific features, but the technique is often similar to that used for oyster mushrooms (bags, pasteurised or sterilised substrate, incubation then fruiting in an air-conditioned room).

Here is a summary table of some major species and their typical mushroom cultivation conditions:

Species of mushroom	Mushroom growing substrate	Incubation (colonisation)	Fructification (key parameters)
Oyster mushroom (Pleurotus) - e.g.: grey, yellow, pink oyster mushrooms	Enriched pasteurised straw (bran), or straw/sawdust mix. Sometimes sterilised enriched sawdust for certain strains.	10 to 15 days at ~24 °C. Mycelium very rapid, colonisation visible in a few days. High CO₂ maintained in incubation.	Temperature 18-20°C (depending on the species, pink oyster mushrooms will fruit even at 25°C). Humidity 80-90 %. Need moderate fresh air (CO₂ 700 to 1000 ppm depending on variety) and a little light (a few hundred lux). Air renewal in the room: 8 to 10 times the volume per hour. First harvest ~7-10 days after fruiting begins. Subsequent flushes possible every 2 weeks or so.
Shiitake (Lentinula)	Pasteurised straw enriched with bran or hardwood sawdust (oak, beech) enriched with bran, sterilised and compacted into blocks.	6 to 7 weeks at ~25°C. The mycelium colonises and then matures (formation of a brown "bark" on the surface of the block, a sign of good incubation).	T° 18-20 °C. Humidity 85-95 %. High fresh air requirement (CO₂ < 800 ppm). Lighting: at least 16 hours of light per 24H00. Sometimes a physical shock. Three types of shock: - physical, hydraulic and temperature shock. Harvest in 7-10 days once induced. Several flushes (2 to 4) over several months.
Button mushroom (Agaricus)	Compost made from horse manure + straw, fermented then pasteurised (Phase II), seeded (Phase III) then covered with topsoil.	10 to 15 days at ~25°C for colonisation of compost (in potting soil).	This crop is more technical, but in broad terms: T° 16-19 °C. Humidity 85-90 %. Need moderate fresh air (CO₂ < 1500 ppm). No light required (bedding mushroom). Mushrooms emerge through the mould approximately 14 days (if the temperature curve is respected) after fruiting. Harvest for 6 to 8 weeks in 3-4 waves.
Pholiote	Enriched pasteurised straw (bran) or a mixture of sawdust and bran (rich substrate) sterilised in blocks or bottles.	~4 weeks at 22-24°C. Fragile mycelium, requires strict cleanliness.	T° 15° to 20°C. Humidity 90-95 %. Low light levels. Significant fresh air (CO₂ < 1000 ppm). Produces small clusters of mushrooms in about 2 weeks. 2 or 3 flushes possible.

(The exact parameters may vary depending on the strain and installation; the above values are typical orders of magnitude).

As you can see, each species has its own "recipe for growing mushrooms. As a professional grower, you'll need to adapt your facilities and planning to suit the mushrooms you choose. Some growers specialise in one species (e.g. being a mushroom grower specialising in oyster mushrooms), while others diversify to smooth out the risks or fill the market in several segments (e.g. oyster mushrooms + shiitake mushrooms, which makes it possible to offer customers a wider basket).

Controlling mushroom cultivation parameters

Whether you grow one species or several, the control of environmental parameters is at the heart of a successful mushroom farm. There are often four key parameters:

1. Temperature Temperature: This is the main lever for controlling the different phases. A high incubation temperature accelerates colonisation (although care must be taken not to exceed the limit of the species, otherwise the mycelium will die or contaminants will proliferate). A lower fruiting temperature is almost always necessary. Each species has its own optimum fructification range.
2. Hygrometry (humidity) Mushrooms need very humid air to develop properly, otherwise their tissues dry out (causing abortion or deformation). We generally aim for >85 % relative humidity during fruiting, often around 90-95 %. This can be managed with humidifiers (fog generators) and by avoiding dry draughts. Beware, however, of excessive condensation, which can drip onto fungi and encourage bacterial diseases.
3. Ventilation and CO₂ : During incubation, CO₂ is often left to rise (little ventilation) as this encourages mycelial growth and not fruiting. In the fruiting phase, conversely, the CO₂ produced by the mycelium must be evacuated to stimulate the primordias and prevent the mushrooms from "spinning" (growing with elongated stalks and small heads, a sign of lack of oxygen). Each species has its own tolerance to CO₂: oyster mushrooms are quite demanding (they need lots of fresh air). Good aeration, without violent draughts, ensuring a sufficient supply of oxygen, is therefore essential. Air extractors coupled with filtered fresh air intakes are used in mushroom growing rooms.
4. Light Unlike plants, mushrooms (with the exception of shiitake mushrooms) do not need light for their energy (no photosynthesis), but light often plays a role in triggering or directing growth. For example, oyster mushrooms need a minimum amount of light to form their caps properly and to orientate themselves (cold diffuse light is often recommended, equivalent to 12 hours day / 12 hours night for fruiting). On the other hand, others such as Agaricus (button mushroom) and Enoki grow very well in complete darkness. So you need to know what your species needs. Moderate light intensity (a few hundred lux) in a day/night cycle is common for most exotic mushrooms.

In addition to these main parameters, there is the cleanliness/hygiene which is crucial in preventing contaminants (green moulds such as Trichoderma, mucor, bacteria) from spoiling the party. This means cleaning the rooms thoroughly between cycles, filtering the incoming air, wearing clean clothes, etc., especially during the incubation/early fruiting phases when the mycelium is not yet dominant.

Optimising yields and quality

Once the basic techniques are in place, the aim of every grower is tooptimising performance (quantity of mushrooms obtained) and the quality (size, appearance, flavour) of its production. Here are a few tips and levers for optimisation:

• Using high-performance strains : It all starts with the right mycelium. Some strains of oyster mushroom, for example, may produce 20 % more than others or be more resistant to summer heat. Working with a reputable mycelium supplier or substrate supplier that incorporates these good strains is an advantage.
• Choose a rich, suitable substrate As mentioned above, the substrate recipe influences yield. A substrate with a good balance of nutrients will produce more mushrooms. Be careful, however, not to overload with easy nutrients (nitrogen), as this can lead to contamination. Here again, using a substrate formulated by experts (such as EUROSUBSTRAT CALLAC substrates) will ensure you have the best possible base.
• Scrupulously respect the parameters Every uncontrolled deviation (temperature too high or too low for a few hours, poorly regulated humidity) can cost yield. Automation helps a lot (sensors and a PLC to control misting and extraction). Visit your rooms regularly, several times a day, to spot any problems early (an incorrectly placed sensor, a broken fan, etc.) before the mushrooms suffer.
• Harvesting at the right time Neither too early nor too late. A mushroom harvested too early is lighter (and therefore loses potential weight), and too late can sporulate or deteriorate. Find the ideal harvesting stage and organise yourself so that you can pick quickly from the entire surface when it's ready. Careful picking (without damaging the substrate, by removing the plants cleanly) also prepares the next flock well.
• Renew the substrate at the right rate Keeping an exhausted substrate in the room for too long takes up space with little result and can increase health risks. It is often better to remove the blocks after 2 flushes (at least for oyster mushrooms) and replace them with fresh ones, so that the space can always be used for active production. The right rate is calculated on the basis of the cost of the substrate versus the additional harvest expected from an extra flush.
• Keeping a mushroom cultivation diary Record the dates of sowing, induction, harvesting, quantities obtained, incidents, etc. This data will enable you to analyse what works best, compare the performance of different strains or substrates, and continually improve your methods.
• Staff training If you have a team, make sure they understand the imperatives of mushroom growing (remembering to close a cold room door, handling substrates with clean gloves, grading the harvest according to customer requirements, etc.). Raising everyone's awareness of "good practice" can prevent a lot of losses.

By following these paths, a mushroom farm can gradually increase its yields significantly compared with more approximate management.

EUROSUBSTRAT CALLAC's technical support for your mushroom cultivation

At EUROSUBSTRAT CALLAC, we see our role as going beyond the supply of substrates. We are committed to supporting our grower customers in the success of their mushroom cultivation. In practical terms, this means :

• Providing personalised advice on mushroom cultivation parameters: for example, if you are using our oyster mushroom substrates and you notice a delay in fruiting, our experts can help you adjust the incubation time or temperature reduction at the right time.
• Inform you about specific features of each substrate When you receive a EUROSUBSTRAT CALLAC substrate, it is accompanied by recommendations on its best use (e.g. "slit the bag on the top and sides for grey oyster mushrooms, leave in the closed bag for 4 days then open", etc.). Following these instructions will ensure you get the most out of the substrate.
• Remain on hand in the event of a problem: Are you experiencing unusual contamination, or a disappointing flight? Rather than looking for a solution on your own, you can contact our technical team who, with their wealth of experience, will often be able to diagnose the source of the problem (for example, a CO₂ level that's a little too high, or a substrate that's suffered a heat stroke) and suggest solutions. This reactive support can save precious time and prevent the problem from recurring.
• Offer training courses or visits: for new customers, we can organise a tour of our facilities or a visit to your site to discuss best practices for growing mushrooms. These knowledge transfers are part of our support mission.

In short, we don't just want to be a supplier, we want to be a leader. your partner in mushroom growing. Mushroom growing, as we have seen, has many technical facets. Having an ally with 30 years of accumulated expertise in this field is an asset we can put at your service.

Conclusion: combining technology and the living world

Mushroom cultivation is an exciting activity that combines scientific aspects (microbiology, agronomy) and the management of living organisms, with all their unpredictability. Success in this field requires a detailed understanding of the needs of mushrooms and the ability to implement appropriate techniques. This means choosing the right substrate, mastering mushroom cultivation parameters and being vigilant at all times.

EUROSUBSTRAT CALLACwith its high-quality substrates and support, strives to make growers' work easier by providing them with the best "technical" support (ready-to-use substrates, expert advice), so that they can concentrate on the art of monitoring the growth of their mushrooms.

Whether you grow oyster mushrooms, shiitake mushrooms, pholiotes or other speciesWe hope that this overview of mushroom growing has provided you with some useful insights. If you have any further questions or need practical help to improve your cultivation, don't hesitate to contact EUROSUBSTRAT CALLAC. Together, we can pool our skills to bring your mycicultural projects to fruition!