Description of the Morel Project

Indoor cultivation of black morels
An example of our indoor cultivated black morels.

Table of Contents

1. How did our interest for cultivation of morels emerge?

In 1977, when we started studying biology at the University of Copenhagen, we became seriously interested in the biology of edible mushrooms and their possible cultivation. On the basis of various literature studies, we then carried out many experiments with the cultivation of white button mushrooms and oyster mushrooms in particular under private conditions. In the spring of 1978, our lifelong interest in the cultivation of the much more complicated and valuable morels suddenly aroused, as we learned the following interesting points below.

The Black Morel (Morchella sp.), like the Common Morel (Morchella esculenta), are highly prized edible mushrooms. The former, however, is by far the most important international commercial product. Despite more than 100 years of research worldwide, there is no controlled method for year-round commercial cultivation of morels indoors. The global annual turnover of black morels is thus based exclusively on mushrooms collected from the wild in spring.

This very challenging information led to further literature studies and the conduct of numerous private experiments in the period 1982-1986 using mycelium isolated from morels found in the Danish wild.

Then suddenly, in 1986, we heard that an American research group had just patented a controlled method for cultivating morels indoors, year-round (see “Cultivation of Morchella” in the bibliography). Therefore, in the autumn of 1986, we became very eager to try to replicate the American patent first and then, if possible, to improve the method significantly. However, a major question loomed: Where could such advanced research, including climate-controlled cultivation chambers, be carried out in Denmark – and how, if at all, could the project be financed?

2. Many years of morel cultivation research at KVL and KU

Cooporation with KVL and KU
In cooperation with Associate Professor Kaj Bech, who was the head of the then Mushroom Laboratory at the Department of Agricultural Sciences at the Royal Veterinary and Agricultural College (KVL), we succeeded in obtaining funding from the Danish Agricultural and Veterinary Research Council for a morel project, which was initiated on 1 January 1987 at KVL. Throughout most of the subsequent period up to the present day, we have continued the very extensive research work at KVL and later at the University of Copenhagen (KU). Thus, KVL merged with KU on 1 January 2007 and changed its name to LIFE – The Faculty of Life Sciences. On 1 January 2012, the situation changed again, as our great collaboration with KU was merged into the Faculty of Natural and Life Sciences (SCIENCE).

Throughout the years, we have been very satisfied with the cooperation we have had with KVL and KU, which has been based on various forms of cooperation agreements. A very central part of this cooperation has been our rental of various facilities, including advanced laboratory equipment and well-functioning climate chambers of a maximum of 20 square metres.

As mentioned earlier, at the beginning of the period at KVL we received funding from the National Board of Agricultural and Veterinary Research, corresponding to the employment of one person for four years. From September 1988 up to the present day, we have also been funded by the following private companies, except for a few short periods of unemployment:

  • A/S International Morkelproduktion
  • International Svampe Produktion ApS
  • Petersgaard A/S
  • Kunststof Holding ApS

During the whole period from September 2008 up to today we have thus been financed by Kunststof Holding ApS.

As can be seen from the above, over the years of research we have collaborated with a very large number of people from KVL and KU, and not least with the four companies that, through various private investors, have provided most of the funding for the entire project. We owe all these people a very big thank you – not least for their perseverance and belief in the project’s potential!

3. Dissemination and protection of the accumulated knowledge

At the beginning of the morel project, we wrote two articles about our initial work at KVL published in 1987 and 1992 (see bibliography).

In 2006, we filed an international patent application for the cultivation of morels in collaboration with a private patent agency. The application described, among other things, two of the most central cultivation principles which are also used today in our fully developed method for the controlled indoor cultivation of black morels, all-year-round. However, shortly after the application was approved, we decided, on the advice of the Danish Patent Directorate, to withdraw the application before it was published worldwide, as in practice it is relatively easy to circumvent a patent of this type. Therefore, we have decided to keep the key points of our method secret, not least because we are currently considering the commercial possibilities. This is why we are unfortunately unable to provide any more information on the cultivation process than is given on this website.

4. Collection of genetic variants of the Black Morel (Morchella sp.)

According to “Nordeuropas svampe” (see bibliography), the Black Morel (Morchella conica/elata complex) is a species-rich group of closely related species, which are so similar both macroscopically and microscopically, that they are almost impossible to determine without the use of DNA analysis. Since the latter has not been possible for us, and we have therefore been unable to determine how many species we have actually made culture experiments with, we have chosen to use the term Black Morel (Morchella sp.) for all the isolated mycelia from the wild with which we have worked.

Since we started our research with morels at KVL in 1987, we have based our many experiments almost exclusively on the Black Morel (Morchella sp.) and only to a lesser extent on the Common Morel (Morchella esculenta), which we have predominantly found in nature in the form of fruit bodies. After isolation of mycelium from a given fruit body on a special nutrient agar, we used this to produce sclerotia under sterile conditions, which were then entered into our two gene banks. Note that morel sclerotia consist of aggregated, nutrient-rich, winter-hardy, orange-brown cells, which, among other things, form the nutrient background for fruit body formation in spring.

Although, as mentioned above, we have not analysed the DNA of the fruit bodies collected from the wild, we have nevertheless taken the liberty of using the designation “a genetic variant of Black Morel (Morchella sp.)” for a given fruit body, but only if, in the subsequent cultivation process, we were able to ascertain from the isolated mycelium that the variant in question possesses one or more quite specific characteristics, which differ from all other material in the gene bank. Of the many properties we evaluate, the ability to develop sclerotia, conidia and fruit bodies under well defined conditions is particularly important, but the medium size and appearance of the fruit bodies are also of key importance.

Throughout the above period, we have made exciting trips for black morels to relevant locations, mainly in Denmark, but also in Sweden, Austria, Switzerland and France, almost every spring. In addition, we have obtained a good number of fruit bodies, mainly from Turkey. The combined efforts in this area resulted in the isolation of mycelium from as many as 347 different fruit bodies up to May 2021. However, as the fruit bodies were of highly variable quality in terms of freshness and moisture content, we only succeeded in isolating mycelium and subsequently producing sclerotia from 224 of these fruit bodies, which were then entered into the two gene banks. Subsequently, this entire collection of sclerotia formed the basis for various cultivation experiments in order to determine, among other things, how many genetic variants of Black Morel (Morchella sp.) there actually are and, not least, how good the isolated variants are to produce fruit bodies under controlled conditions.

5. Establishment of two gene banks with sclerotia from various genetic variants

From the very beginning of our research at KVL, we established a gene bank at about 3 °C, containing sclerotia from progressively more genetic variants of the Black Morel (Morchella sp.). These sclerotia have served as basis for all experiments carried out in the following years.

However, as it became increasingly clear to us over the years that the various variants lose their ability, to a greater or lesser extent, over time to exploit a given nutrient source or develop fruit bodies, we were forced to develop a better storage method. It was obvious to try to develop a method for storing the sclerotia under optimal conditions in liquid nitrogen at ÷196 °C, which we actually succeeded in doing in 2016. Subsequently, our gene bank was established at this extremely low temperature in November 2018. This always contains an abundant supply of sclerotia from our five most valuable genetic variants, as well as typically about 10 newly discovered variants from the last spring, which are tested in various ways. All frozen variants should thus be assured of “eternal youth” for many years to come.

Equipment used
Some of the equipment used for freezing mainly our five most valuable genetic variants of black morels at ÷196 °C.

6. Production of sclerotia and mycelium rich inoculum

Over a number of years, we worked intensively to build up as broad a knowledge of the sclerotial stage of the Black Morel as possible. Thus, we uncovered how a large number of physical, chemical and biological parameters affect the formation of sclerotia both qualitatively and quantitatively. This resulted in the development of an optimal method for the production of sclerotia under sterile conditions. Subsequently, the sclerotia are used in our two gene banks and as inoculum in various fruit body experiments.

As we learned that in some cases it is advantageous to use mycelium rather than sclerotia as inoculum in the cultivation process, we also spent some time developing an optimal method for producing a sterile, mycelium rich inoculum. This included the precise identification of the physical, chemical and biological parameters that ensure a product of the highest quality.

Sclerotia lumps-The Danish Morel Project
Large clumps of fine sclerotia produced under sterile conditions.
Mycelium rich inoculum produced under sterile conditions
Mycelium rich inoculum produced under sterile conditions. The substrate is crumbled just before use.

7. Several attempts to replicate the US patent

The year of 1988 was a very special year for us. At that time, we started our very first attempt to cultivate black morels under climate controlled conditions at KVL. The plan was to try to replicate the American patent mentioned earlier (see “Cultivation of Morchella” in the bibliography) and hopefully harvest the first morels. However, this proved to be impossible. Despite countless attempts over a number of years, combining every conceivable parameter in various ways within the framework of the patent, the morels just would not appear. Therefore, we became increasingly frustrated with the situation and started to include various physical, chemical and biological parameters in the experiments which were not covered by the patent. But unfortunately without any success!

So it came as a great relief when we suddenly learned that other scientists worldwide were also having trouble replicating the US patent. In fact, it seems that the patent’s specifications only give rise to a successful fructification in connection with just a very few variants.

8. Completion of four subprojects as inspiration for the morel project

We gradually realised that we had to look beyond the US patent for important clues as to how the controlled indoor cultivation of black morels might be realised. Therefore, we carried out four subprojects in the following years, which are described in detail in appendix 1-4.

9. Emergence of the first indoor black morels and subsequent effective optimisation

Emergence of the first black morels indoors
Immediately after the first black morels had emerged outdoors in spring 2004, as described in Appendix 4, we planned an experiment under indoor conditions that would copy the successful outdoor experiment in as many ways as possible. To our great delight, everything went as we had hoped. Thus, already in autumn 2005, the finest black morels appeared in the cultivation boxes with an average yield of 349 g per square metre.

One of the first cultivated black morels
One of the first black morels of variant 147 emerged indoors in autumn 2005.

Now we finally had a valuable blank test, which allowed us to start an efficient optimisation of all the relevant parameters in the indoor cultivation process. The hope of being able to develop a fully controlled method for the indoor cultivation of black morels all-year-round was now suddenly somewhat more realistic. The main elements of the optimisation process are outlined below.

Testing of various relevant cultivation methods and lineups
After the indoor cultivation breakthrough in 2005, we tested several potential cultivation methods and lineups over a number of years until we finally selected the most interesting method at the end of 2015, which we have further improved since then. Throughout the development work, we have predominantly used special Rako boxes of 0.11 square metres each as cultivation units. In an attempt to develop a larger and more rational unit, we designed and manufactured a so called “pallet cultivation system” in early 2018, with a surface area of 0.87 square metres, which in principle corresponds to how a commercial cultivation system should be constructed. The system is mobile, as it can be moved around very easily with a pallet lift. The pallet cultivation system is based on a very specific and crucial cultivation principle, which is not mentioned on this website.

Mobile morel pallet cultivation system
Technical drawing of the fully developed mobile pallet cultivation system, the details of which we unfortunately cannot reveal.

Development of an artificial morel soil 
Already in 2005, we were convinced that it was essential to develop a well defined, artificial morel soil to meet our desire to develop a stable and efficient indoor cultivation method. If a more or less random, natural soil is used instead, the risk of unwanted bacteria, fungi and pests suddenly introducing themselves, resulting in a reduced yield of morels, is far too great. Furthermore, the varying mineral content of natural soil from one period to the next will give rise to problems of various kinds.

As a consequence of the above issue, we decided to develop an artificial morel soil. Here we chose to use our artificial truffle soil, mentioned in Appendix 1, as the starting point for the experiments because of the close relationship between morels and truffles. As a result of this lengthy development work, we now have a perfect and well defined artificial morel soil, composed of five different natural products in a precise ratio to each other and with a carefully adjusted mineral content. During the work, we always had in mind to include ingredients with as high a product safety as possible.

Development of two commercially suitable nutrient substrates 
Also in 2005, we agreed that the previously used nutrient source based on coniferous bark, which gave rise to the first appearance of morels both outdoors and indoors, now needed to be replaced with a more stable and effective nutrient source. Therefore, we initiated a countless series of experiments under both sterile and non-sterile conditions, in which all kinds of more or less enriched organic nutrient sources were tested and evaluated against a subsequent fruit body formation. During this development work we learned the crucial fact that a satisfactory yield of morels can only be achieved if the entire cultivation unit is in ecological balance. In particular, it is important that the mineral content and the carbon/nitrogen ratio of both the morel soil and the nutrient source are carefully balanced.

As a result of the above work, we now have the recipe for two very different organic nutrient sources, one based on a sterile and the other on a non-sterile colonisation with morel-mycelium. Both sources of nutrients give rise to an impressive fruit body formation that could be used on a commercial scale. The nutrients are also cheap, stable and easy to obtain.

Is it beneficial to include plants in the cultivation process?
As can be seen from the photo and video material on this website, grass is part of the overall cultivation process of black morels. Unfortunately, we cannot reveal any further details.

Development of an optimal climate programme 
Over a number of years, we developed an optimal climate programme for the entire cultivation process using the various climate chambers. We worked on the temperature requirements, the length of the day, the intensity of the light and the spectral composition of the light. This includes the successful replacement of incandescent lamps with the highly energy-saving LED light. Finally, we carried out humidity experiments and also exposed the morel-mycelium to “artificial rain” of varying duration. The climate programme entails the following points:

  • Optimal competition conditions for the morel-mycelium.
  • It is possible to predict fairly accurately when a given variant will appear on the cultivation beds and later on harvested.
  • The average size of the morels can be regulated to a certain extent.
  • A maximum yield of morels.

10. Achieved fruit body results in the climate chambers throughout the optimisation period from 2005-2021

Since the first black morels appeared indoors in 2005 and up to and including 2021, we managed to produce fruit bodies from 73 out of 80 quite characteristic genetic variants of the Black Morel (Morchella sp.), which we found and isolated from the Danish wild since spring 2003. This corresponds to a success rate of about 90%, which apparently far exceeds the results achieved by other researchers in testing the US patent mentioned earlier (see “Cultivation of Morchella” in the bibliography).

cultivated black morels
Here is a small sample of the fruit bodies that we have managed to cultivate in the climate chambers. At the top left, variant 192 and at the top right a mixture of fruit bodies from variants 195 and 198. Below, variant 240 on the left and 243 on the right. Overall, we have managed to produce fruit bodies from 73 genetic variants under these highly controlled conditions.

Our cultivation research also revealed the interesting fact that there is a relatively large difference in the appearance, size, development rate and productivity, when genetic variants are cultivated under controlled, indoor conditions. To look for new variants in the wild in spring can be compared to looking for gold, since gold in this context corresponds to finding a variant which, when cultivated, is both attractive, weighs at least 25 g on average (compared to the normal weight of about 7 g), develops at maximum speed and produces a yield of at least 3 kg of black morels per square metre.

Overall, we can conclude that variant 195 and 234 are our most productive variants. We thus succeeded in obtaining a yield of 4.2 kg of morels per square metre from variant 195 within a total cultivation period of 22 weeks, corresponding to an annual production of 10 kg per square metre. For variant 234, we obtained a yield of 4.1 kg of morels per square metre within a cultivation period of 20 weeks, corresponding to an annual production of 10.7 kg per square metre. Unfortunately, as the fruit bodies from 234 weighed only 8.4 g on average, they were growing so close together within a large part of the cultivation area that they became more or less deformed and were very difficult to harvest.

In conclusion, since the appearance of the first indoor black morels in 2005, we have harvested a total of 152.5 kg of morels in the climate chambers at KVL and KU. It is also a fact that the yield of black morels in kg per cultivation round has been increasing overall from 2013 onwards, with the highest yield of 26.7 kg in the latest round in 2021.

11. A controlled method for year-round indoor cultivation of black morels is finally developed

Today, we are very pleased to announce that, after the implementation of the optimisation programme mentioned earlier, we finally have a fully developed method for the controlled indoor cultivation of black morels, all-year-round. This means that the method contains a combination of all the optimal conditions we identified, such as the best growing unit, genetic variant and morel soil, as well as the optimal nutrient substrate and climate programme. We can therefore conclude that the method is now so well developed that a commercial production can be started after an appropriate automation of the cultivation process.

As the final cultivation unit we use the previously mentioned pallet cultivation system, which in principle corresponds to how a commercial cultivation system should be constructed. The cultivation system of 0.87 square metres is colonised with morel mycelium from the same genetic variant during fructification, so that the cultivation unit can be considered as one large organism. In total, we produced 10 of these units, that precisely fill the space in the largest of KU’s climate chambers.

Variant 195 has overall proven to be our most valuable with the following key cultivation characteristics:
  • The fruit bodies develop quickly and can thus be harvested relatively early.
  • The fruit bodies are very good-looking and become unusually large with an average weight of about 25 g, are distributed relatively evenly over the cultivated beds and are therefore very easy to harvest.
  • The variant is very productive, corresponding to an annual yield of about 10 kg per square metre.

To protect the environment as much as possible, we never use pesticides in the cultivation process to kill for example fly eggs and fly larvae in the morel soil. Instead, we use selected beneficial nematodes and mides that actively seek out and eat both eggs and larvae. Furthermore, we learned that incandescent lamps in the cultivation process can be replaced with suitable LED lights, which are very energy efficient.

Since we have been striving throughout the optimisation work to develop a cultivation method that is ecologically balanced and ensures optimal competition conditions for the morel mycelium, people can move freely in the cultivation room without using protective clothing or similar equipment.

small cultivated morel mushrooms
Three photos of small black morels of about 2-10 mm in height, emerged on one of our cultivation beds.

The timelapse video shows a gradual development of fruit bodies of variant 195 over a period of 11 days in June 2021.

Cultivated black morels - variant 195 - The Danish Morel Project
Variant 195 has overall proved to be our best variant, as it is very productive and develops large fruit bodies, which are well distributed on the substrate surface.
Cultivated black morels variant 234 - The Danish Morel Project
Variant 234 is our second best variant. We managed to achieve an annual yield of this variant equivalent to 10.7 kg of morels per square metre.

Harvest of fruit bodies of variant 195 from the fully developed pallet cultivation system on 30 June 2021. The total yield was about 3.7 kg of black morels from the cultivation unit, corresponding to about 4.2 kg per square metre.

12. How is the quality of the cultivated and prepared morels?

Our indoor cultivated black morels are generally of very high quality and are, almost regardless of which variants we work with, really good looking. This is partly due to the fact that we harvest them at a culinarily optimal time. The mushrooms are also always completely clean, free of dirt, grit and small animals and without damage from snail bites, for example. Both fresh and dried morels can therefore be prepared without prior brushing and rinsing. These positive characteristics have led to offers of up to 1500 DKK per kg of fresh morels.

indoor cultivated black morels
Two examples of top quality morels that are fully or partially ready for harvesting.

If you wish to dry the morels, this can be done in a large drying cabinet that we designed and manufactured a few years ago. In the cabinet it is possible to dry about 16 kg of fresh morel caps at a time in about two days at an optimal temperature and humidity. The stems are cut off before drying due to the general fact that morel stems become relatively tough after soaking in water.

Indoor cultivated black morel mushrooms ready to be dried
After filling the drying cabinet with the freshly harvested and cut black morels, the lid is put on. The cabinet is then placed in a dry, suitably warm room, and the four fans are switched on.
Dried cultivated black morels in glass jars
A small sample of the many cultivated black morels that we dried in the recent years.

Over the years, several well-known chefs in Denmark have tasted our fresh and dried black morels and been very excited with both the quality and the taste. Below is the essence of master chef Kenneth Toft-Hansen’s assessment of our dried black morels during his participation in the “Bocuse d`or” in Lyon in 2015 (the unofficial World Championships for chefs), where our morels were included in the main course. Kenneth achieved a sixth place at the championship, while he was voted the world’s best chef in 2019.

  • The appearance, consistency and aroma of the morels were of exceptional quality both before and after cooking. The flavour after cooking was also excellent.
  • The morel soaking water was excellent for making sauces etc. because of its strong flavour and lack of impurities. This is in big contrast to the fact that the soaking water used in the preparation of wild, dried morels is usually discarded.
  • After cooking, the dish tasted as if it had been made from fresh morels. This is because no bitter substances or the like were present in the morels, presumably as a result of the optimal drying process which has been used. This differs from the fact that the vast majority of dried morels on the world market contain greater or lesser quantities of unwanted bitter substances.

13. The future of the morel project

In the coming years, the plan is to continue our research activities at KU in an attempt to further improve our otherwise fully developed indoor cultivation method.

Another extremely important and exciting area of work is to continue our search for new, particularly valuable morel variants in the wild in the spring, which could replace our best genetic variants to date.

However, the overriding and most exciting challenge, we face in the coming period, is to find the best way to commercialise the fully developed indoor cultivation method.

14. Other research projects around the world

For more than 100 years, scientists around the world have worked intensively to develop methods for both indoor and outdoor cultivation of the highly prized morels.

By far the most interesting work in this field, in our opinion, was the publication of the American patent mentioned earlier (see “Cultivation of Morchella” in the bibliography), which described a controlled method for indoor cultivation of morels. On the basis of this method, as far as we are aware, morels were actually produced commercially for a long period, but subsequently ceased due to serious problems.

Based on “A comprehensive review on Morchella importuna: Cultivation aspects, phytochemistry and other significant applications” (see bibliography) and other sources, we therefore conclude that in 2021 there is no controlled method worldwide for the commercial indoor cultivation of morels, throughout the year.

However, especially in recent years, a significant outdoor production of black morels has been established, mainly in China, with harvesting only in spring. Very large areas have been used, but due to major problems such as soil conditions, pests and climate, the yield of morels is variable and often very low. In some places, however, some form of climate management is used, resulting in higher and more stable yields.

15. Bibliography

Kirk, J., Kirk, K. & Bech, K. 1987: Dyrkningsforsøg med morkler. – Ugeskrift for Jordbrug 45: 1387-1390.

Kirk, J., Kirk, K. & Bech, K. 1992: Dyrkningsforsøg med morkler. – Svampe 25: 5-10.

Læssøe, T. & Petersen, J. H. 2019: Nordeuropas svampe.

Ower, R. D., Mills, G. L. & Malachowski, J. A. 1986: Cultivation of Morchella. US Patent no. 4594809.

Ower, R. D., Mills, G. L. & Malachowski, J. A. 1988: Cultivation of Morchella. US Patent no. 4757640.

Ower, R. D., Mills, G. L. & Malachowski, J. A. 1989: Cultivation of Morchella. US Patent no. 4866878.

Petersen, J. H. 1998: Svamperiget.

Sambyal, K. & Singh, R. V. 2021: A comprehensive review on Morchella importuna: Cultivation aspects, phytochemistry and other significant applications. Folia Microbiologica 66: 147-157. 

Appendix 1: Development of mycorrhiza between the Summer Truffle (Tuber aestivum) and hazel in an artificial, well defined soil

Description of the experiments
Summer Truffle (Tuber aestivum) is a valuable and rare edible mushroom in Denmark, which is closely related to morels. The fruit bodies develop from accumulated nutrients in the mycorrhiza, which typically develops in association with oak and hazel. As the composition of the soil largely determines how well the mycorrhiza develops, we set out to investigate, on the basis of a very large number of soil analyses, whether it was possible for us to develop such an effective, artificial and well defined truffle soil. Based on summer truffles from Italy and Sweden, as well as our own finding of a 130 g truffle from Denmark, we succeeded in this, as fine and dense mycorrhiza was subsequently developed in various pots as well as in an outdoor experimental area of 36 square metre. 

Summer truffle found in Denmark
Summer Truffle of 130 g found in Denmark.
Mycorrhiza - The Danish Morel Project
Microscope photo of mycorrhiza between Summer Truffle and Hazel developed in one of our experimental test flasks under sterile conditions.

The 36 square metre bed was set up in 2001 to try and develop large amounts of truffle mycorrhiza on four hazel plants in our developed artificial truffle soil – and perhaps subsequently the much sought after truffle fruit bodies. As a result of the gradual development of mycorrhiza in the bed, we observed the following very positive results over the following years:

  • The leaf colour of the hazel changed gradually from yellowish (chlorotic) to fine green during the first growing seasons despite a very high lime content in the soil.
  • In the first years, large amounts of weeds appeared on the bed, mainly dandelions. However, in subsequent years the weeds gradually disappeared, apparently as a result of the release of plant inhibitors into the soil by the truffle mycelium. The phenomenon is known from nature as "burnt out", which is typically seen in connection with the development of large amounts of truffle mycorrhiza in the soil and often also the coveted truffles.
  • During 2007, mycorrhizae developed particularly well within the trial area, strengthening our high hopes that the first ripe summer truffles could be dug up from the area, probably in November 2007.

It therefore came as a shock to us when we were suddenly informed that the bed unfortunately had to be closed down in the summer of 2007 to make way for the construction of a larger building complex on KU’s areas.

Inspiration for the morel project
Fortunately, as we had hoped, the extensive work on the summer truffles subsequently yielded some important knowledge. After minor adjustments, the artificial truffle soil, that had been developed, was found to be very suitable for the controlled cultivation of black morels.

Appendix 2: Controlled indoor cultivation of Sclerotinia sclerotiorum from sclerotia

Description of the experiments
According to “Nordeuropas svampe” (see bibliography), Sclerotinia sclerotiorum occurs as a parasite on roots, stems, flowers, fruits and seeds of various herbs. As the species is closely related to the morels, and also develops fruit bodies from accumulated nutrients in sclerotia in spring, we decided at a relatively early stage to investigate this species further. We therefore began to find the most efficient way to produce large quantities of 2-5 mm black-grey sclerotia and then transform them into fruit bodies. Fortunately, after many trials, we were able to make both processes work very satisfactorily in 1998. Thus, from just one sclerotium, we were finally able to develop between two and as many as 19 spore-producing fruit bodies.

Sklerotier Sclerotinia sclerotiorum
One of our experimental trays containing 5 x 8 rows of black-grey sclerotia from Sclerotinia sclerotiorum. Note that all sclerotia have developed fine, brownish fruit bodies.
Close-up of sclerotia Sclerotinia sclerotiorum - The Danish Morel Project
Close-up of sclerotia from Sclerotinia sclerotiorum, all of which have developed about six perfect fruit bodies.

Inspiration for the morel project
Several of the results obtained with Sclerotinia sclerotiorum were of great use in our final method for cultivating black morels, especially in the difficult field of activating sclerotia to develop fruit bodies.

Appendix 3: Identification of the optimal conditions for the development of the conidial stage of the morel

Description of the experiments
Under certain conditions, the mycelium of the black morels develops an asexual stage in the form of conidia, which appears as a whitish coating on typical soil surfaces or a given nutrient source. Since a profound knowledge of conidial formation might provide some important clues to the understanding of what triggers the morel mycelium to form fruit bodies, we conducted a series of experiments centred on this topic many years ago. The experiments revealed how conidial formation is controlled by the given soil conditions, the nutrient source, the microclimate and, not least, by the genetic variant used for inoculation.

The black morel conidia stage - The Danish Morel Project
The conidial stage of the black morels is seen as a whitish coating on the soil surface in our culture boxes.

Inspiration for the morel project
Now, several years after the implementation of the experiments, we can see that many of the conditions that are optimal for conidia formation also play a significant role in fruit body formation of black morels.

Appendix 4: Outdoor cultivation of black morels 

In 2003, after a long period of unemployment and with no prospect of raising more money for our research, we suddenly found ourselves in the very unfortunate situation of not being able to stay at KVL. However, we still had a small hope of being able to produce the first black morels. In autumn 2003, we built three morel beds outdoors under private conditions, based on a very thorough analysis of a black morel location in spring 2003, where conifer bark had been laid in 2002.

April 10, 2004 still stands as a great day for us. On that very day, we discovered a large number of small, fine black morels in the three beds, corresponding to the genetic variants 146 and 147, which we found and isolated ourselves from the above-mentioned location. The subsequent yield of variant 146 was 538 g of morels per square metre, while the maximum yield of variant 147 reached 1108 g per square metre.

A bucket full of our very first cultivated black morels
The very first black morels of variant 147 harvested outdoors in spring 2004.

This decisive breakthrough meant that from autumn 2004 we could again raise money and continue our work at KVL and later KU, although now concentrating on the increasingly efficient cultivation of our own morel variants both outdoors and later indoors.

In the following five years, we continued to optimise outdoor cultivation in various small beds. In parallel with this, we tried unsuccessfully to grow large quantities of black morels outdoors at Petersgaard Gods on southern Zealand in 2005-2006, which was reported in several Danish newspapers. The reason for the negative result was that the inoculation material was not optimal, the red spruce bark used was of too poor quality, and we had not taken sufficient account of the harsh, unstable, outdoor environment.