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1. THANKS I am grateful to Alla Safray. If she hadn’t reproached me with my laziness in an appropriate to her gentle and delicate form, this article wouldn’t have been written yet for a long time. I am grateful to Aleksey Prisyazhnyuk (Kherson) and Vitaliy Vorona (Kramatorsk, Donetsk region) for permission to use the materials received on their farms and for their excitable participation in the writing of the final variant of this article. I am grateful to Sergey Morozov (agricultural sector “Mokrinskiy”, Nizhniy Novgorod region) for permission to use the materials received on his farm. 2. FOREWORD. So it turned out, that last years I worked as the main technologist on the large and largest enterprises DEALING WITH industrial production of mushrooms in CIS. Since May, 2006 I work on my own. I am engaged in technological support of mushroom farms. I am thinking of founding a specialized consulting firm. What has changed? I have to travel a lot. There is an opportunity to visit fungi culturing parties… I met abnormalities in development of pleurotus fruit bodies which I had never seen so far at the enterprises I was working at. It must be confessed I referred it to the fungi cultivation folklore. My picture archives grow with menacing speed. And there is also a chronic shortage of time which I need for processing and analyzing collected material. Though, there are some topics I am possessed by. And then in our house the phrases like: «Daddy, are you here now or where?» can be often heard. Dear colleagues, here I represent to your discussion my reflections on the theme: « INFLUENCE OF CLIMATIC PARAMETERS ON PLEUROTUS FRUIT BODY FORMATION » 3. INTRODUCTION. Several years ago the article written by F.F. Karpov with remarkable illustrations was published in our magazine. It was the first correct attempt in Russian to systematize deviations of pleurotus fruit body formation, depending on various faults of climatic cultivation parameters. You certainly have heard a lot of interesting things from your colleagues, venerable mushroom growers, and from popular lecturers about distortion of cap


formation, stalks of hymenophore plates depending on climatic parameter deviation. But, as it seems to me, all these reasonings have two common disadvantages: 1) nobody brings QUANTITATIVE values of these parameters when considering their influence on a fruit body formation; 2) nobody gives a binding to definite strains of pleurotus; I suggest: I shall try to state my supervision, confirm them with pictures and analyze them. And you will read them attentively and in turn analyze. And if you do not agree with something and CAN GIVE A REASON of your objection, please do write to me. Maybe something useful to all of us will be born. Do you agree? 4. WHAT DOES MUSHROOM NORMAL GROWTH DEPEND ON? The common opinion is that growth and form of a mushroom fruit body is influenced by the following climatic parameters in a growing room: carbon dioxide concentration, air relative humidity, temperature and, in much smaller degree, light exposure. Few authors add also air motion speed around fruit bodies. I stated my opinion on the given question in the article published in 2006: «Now we can measure CO2. And what for?». Let's try to understand each factor separately. 5. CONCENTRATION OF CARBON DIOXIDE. Pay your attention to PICTURE 001.

The history of this PICTURE. Substrate blocks after first flush of fructification are switched to the mode of rest. Supply of fresh air is blocked. Recirculation is opened 100 per cent. The ventilation system capacity has probably not decreased. Owing to the boiler-house malfunctions there is a lack of steam for mode maintenance in two substrate fermentation tunnels and heating of the growing room. The temperature in the growing room has not practically changed for 2 days and was 14°С. CO2 concentration within the first day has risen up to 1 500 ppm, second day - up to 2 000 ppm. Air humidity remained at 90 - 92 % according to the operator records. On one of substrate blocks in the zone of active air movement a small concretion of mushrooms remained. The strain is NК - 35.


I.e., it is possible to consider that only concentration of CO2 has changed. And here is what we received. See PICTURE 001. On PICTURE 002

you can see which distortions occurred in the form of fruit bodies at increase of CO2 concentration up to the level of 1 300 ppm during the night owing to operator’s mistake. The strain is NК-35. Air humidity did not significantly vary. The operating mode of ventilation system did not vary. On PICTURE 003

you can see absolutely similar situation. Only the concentration of CO2 rose to 1 050 - 1 100 ppm during the night. The commercial form of a mushroom joint of the strain NК-35, grown in the same room but without deviation of climatic parameters, is shown on PICTURE 004.


The set climatic parameters are: concentration of CO2 900 - 950 ppm (so-called fuel-economic mode), air humidity 92 - 94 %. The ventilation system capacity is the same, as on the previous pictures. As it seems to me, we can draw preliminary conclusions for the strain НК-35: - at sufficient speed of air motion (however, we shall speak about air motion later) air relative humidity about 92 - 94 % and concentration of CO2 near 900 - 950 ppm we can grow mushrooms of market quality; - the increase in CO2 concentration up to a level of 1 050 ppm during a night causes «reversing» of mushroom caps upwards; - when concentration of carbonic gas increases further, stronger «reversing» of mushroom caps and lengthening of their stalks is observed; - very high concentrations of CO2 practically completely suppress development of caps. A stalk elongates and becomes thin. A mushroom as if tries to reach the area of fresh air. (Here I recollect a recently read brochure, in which the author recommends to realize forcing treatment of pleurotus fruit bodies at CO2 concentration 0,5 - 0,6 %, i.e. 5 000 - 6 000 ppm! God save us from this kind of “manual”!) 6. AIR RELATIVE HUMIDITY. By the descriptions in the literature and stories of both beginners, and venerable mushroom growers the attributes of excessive air humidity are: - thick, as if goffered plates of hymenophore, - thick, short, barrel-like stalk of a mushroom, - not developed and frequently funneled cap. By the way, in April, 2005 at the seminar in Donetsk I heard one more interesting version from the respected consultant and lecturer: «The attribute of the increased air humidity is the ZIGZAG form of a stalk». During 6 months I daily came to work with my camera. At first there were 7, then 9 growing rooms with the general capacity of about 550 tons of substrate. And there were no cases with barrel-like or zigzag line stalk! Though, we tried to work when air humidity was more than 90 %. There were mistakes of operators at which air humidity exceeded 95 - 96 %. And again no "barrel-like" stalks appeared! My


curiosity has not come yet so far to do experiments in the room containing 50 - 55 tons of fructifying substrate! Suddenly an idea came: And what, if to direct a jet of finely sprayed water on the growing joint? Is it possible to have greater humidity? So I did. See PICTURE 005.

Again it was the strain NК-35. We received goffered «fat» hymenophore. And the other properties did not show themselves! Maybe NК-35 is not an appropriate strain for testing? I have repeated the experiment with A 3000. The result is on the PICTURE 006.

Something comes out of the standard point of view. 7. THE MOISTURE EVAPORATION SPEED. Let's try to discuss. A mushroom lives on reception of a nutrient solution from mycelium in a substrate block. Unlike plants, a mushroom has no system of active transport. I.e. mushroom metabolism intensity is determined by the speed of water evaporation from a fruit body. The speed of evaporation changes in the following way:


- with increasing of air relative humidity the speed of water evaporation from the area of a wet surface falls. - with increasing of air flow speed above a wet surface speed of water evaporation from the area increases. - with increase of evaporation surface in equal conditions water evaporation increases. Probably the key factor is exactly a speed of air flow around the evaporative surface. When this idea was finally generated, I began to stay at work for nights. Several evenings I made mesh "barrels", fitted them with the film and tried to create a protective screen around concretions of fruit bodies. I tried to create a stagnant zone around several fruit bodies not to increase air humidity and concentration of CO2 around them. I should note that if I haven’t had an aspiration psychrometer and the Mickey Foley’s CO2 concentration measuring device, I could not do anything! At last in couple of weeks I guessed to replace a plastic foil by gauze and received the first results: - PICTURE 007.

The result of artificial stagnant zone formation around mature fruit bodies of pleurotus strain M 5. - PICTURE 008.

The result of artificial stagnant zone formation around mature fruit bodies of strain NК-35.


Then the same experiment was conducted two months later with young mushrooms of the strains A 3000 (PICTURE 009)

and К-12 (PICTURE 010).

Intensive dark color of the caps of fruit bodies is explained by low temperature in the growing room. (10 - 12 °С) I would like to emphasize once again: in neither of these cases the concentration of CO2 exceeded 850 ppm, and air relative humidity - 93 %. The quality of other fruit bodies in these growing rooms remains unchanged. By the way, in this case the reversing of mushroom caps and corrugated plates of hymenophore are possible to explain as attempt of a mushroom to increase the area of moisture evaporation. I can refer some deviations from conventional typiform to impossibility of creation of a small stagnant zone with enough low speed of air motion in growing rooms with good distribution of air. So I would suggest to change the expression «too high air relative humidity» with «insufficient speed of evaporation». 8. IMPORTANCE OF QUALITATIVE AIR DISTRIBUTION IN A GROWING ROOM Now many mushroom growers already competently calculate which quantity of air is necessary to supply to the growing room reasoning from loading it with the substrate. For at least 2 years I don’t meet attempts to calculate the capacity of ventilation system reasoning from physical volume of the room. I shall illustrate the given position with two series of pictures:


PICTURES 011, 012, 013

are made lengthways in the first block row from the central pass, in the middle and at the end of the row, accordingly. The strain A 3000 was used. The temperature of growing is 12 - 14 °С. Rh = 90 - 93 %. The concentration of CO2 is in the range of 800 - 850 ppm. Before the next loading of the growing room with the substrate the entrusted representative of the director doubled the quantity of air nozzles in each pass without any permission. It is possible to assume that in such a way he tried to reduce resistance of air distribution system in the growing room to increase the fan delivery. But, naturally, he halved the air flow speed from air nozzles … The result is shown on the series of PICTURES 014, 015 and 016


from the center of the growing room to the wall. I tried to take pictures at the same locations of the substrate blocks. The Strain A 3000. The temperature of growing is 11 - 13 °С. Rh = 90 - 93 %, CO2 concentration is in the range of 800 - 850 ppm. I ask you to compare these series of pictures once again. In fact, nothing has changed, except for speed of air motion between "the walls" of the substrate blocks. As a result of the first cycle of cultivation 14 % of the received mushrooms have been sent for industrial reprocessing because of the low fruit bodies quality. In the second flush there were 32 %. You can give an economic estimation of this unreasoned decision. Initial data: - the loading of the growing was 55 tons of a substrate. - the farm’s average productivity in 2 flushes was 19 %. - the productivity in 2 flushes after inserting 2 additional nozzles in this growing room was a little less than 16%. - the price for a mushroom sent for processing was approximately 40 cents for kg lower than for a mushroom sold in retail trade. Impresses? 9. THE BOUNDARY LAYER. So, we assumed that distortion of a mushroom fruit body formation at normal carbonic gas concentration is caused not so much by high air relative humidity, as by low speed of moisture evaporation from the present fruit bodies. Well, you will ask, why does this Yakushenko attach importance to those formulations? Patience, please. If it is possible to understand the reason correctly and the mechanism of observable phenomenon occurrence, we shall have an opportunity to predict correctly the consequences of our actions and to correct expensive mistakes. Let's argue again:

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A mushroom perceives CO2 concentration, air humidity and temperature with its receptors. We suppose that these receptors act a little above the surface of a mushroom. But, in any case, they measure values of the listed parameters directly in the air boundary layer around the fruit body. The mushroom evaporates water, exhales carbonic gas. I.e. sates this boundary layer with water vapor and carbonic gas. Carbonic gas and vapor diffuse to air. This process is slow enough. And the “thinning” of our boundary layer accelerates the removal of CO2 and reduces its concentration near receptors. If this reasoning is true, we can normalize the form of fruit bodies and all mushroom growth process without increase of general air input per a growing room. We shall merely increase the air flow speed directly above fruit bodies and thereby “tear off” the air boundary layer, as well as save energy on air preparation. Or, conversely, sustain serious losses. It has been shown in the previous section. Is it really that simple? Let's think, how is it possible to check up such assumption? How is it still possible to thin a boundary layer if there is no opportunity to increase speed of air motion in a boundary layer? Do you remember that according to the various authors opinions the speed of exchange processes in a mushroom halves at 5 - 10 °С temperature decrease? At the reduction of temperature the speed of CO2 and water vapor excretion will decrease. At the constant speed of diffusion it will cause reduction of thickness of a boundary layer. Is that true? It is necessary to check up the given assumption. Within the last 3 months on three various farms I saw a similar picture. See PICTURES 017 and 018.

In the first case we have a typical situation of "too high air humidity» - a thick stalk, fat goffered plates of hymenophore and pressed cap… It is badly combined with the real air humidity, it is only 80 - 83 %! But the concentration of carbonic gas between the blocks is near 1 050 ppm! The temperature is approximately 15 °С. It seems that in this case there is more logic in increasing fresh air inflow for reducing the concentration of CO2, and to warm up a supplied air to decrease its relative humidity. In the second case the bad thing is that the concentration of CO2 might be increased as the bottom part of stalk is extended. But at the moment of arrival there was a classical picture of increased air humidity. And really, at the moment of my arrival we had concentration of CO2 near 800 ppm and air humidity near 92 - 94 %.

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The temperature was approximately 16 °С. The recirculation is completely disabled, only input ventilation is functioning. It would seem necessary to warm up the supplied air to decrease its relative humidity. The general things in both cases were enough powerful ventilation systems and absolutely unsatisfactory air distribution systems in the growing room. They did not provide satisfying air distribution in the room and along the substrate block rows. The only urgent way to reduce thickness of an air boundary layer and to normalize process of fruit bodies growth in both cases, to my opinion, was the decrease of temperature in the growing room and, curiously enough, the increase of recirculation fraction in the input system of ventilation. In the first case it was necessary to lower the temperature in the growing room to 13,3 °С. Thus it was possible to pass to a mode of approximately 55 % of recirculation and 45 % of fresh air. 3 days after the survived mushrooms began to look like the ones on PICTURE 019.

In the second case the process was normalized at gradual reduction of the temperature to 13,5 - 14 °С and transition to the ratio of fresh air - recirculation of 50/50. Three days later we made the PICTURE 020.

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As it seems to me, the argument is convincing enough in favor of reduction of a boundary layer thickness due to the decrease of temperature in the growing room in emergency. But once again I would like to emphasize - I did not meet such catastrophic effects in the growing rooms with correctly calculated and accurately executed system of air distribution! 10. HIGH SPEED OF AIR MOTION. If moisture evaporation is to low - a mushroom tries to increase evaporation speed by increasing the area of evaporation: - It turns its cap inside out, puts the plates of hymenophore under air stream, - gofers plates of hymenophore and makes them high. What if the speed of evaporation is slightly above optimum? What can a mushroom do for its reduction? See PICTURE 021.

The mushroom as if bashfully covers the plates with edges of the cap. If the quality of fruit bodies is more or less equal in a growing room, and if the share of such "bashful" mushrooms does not exceed 20 % - there is nothing wrong. I did not notice any reduction of productivity. 11. COMBINED INFLUENCE OF SEVERAL FACTORS Unfortunately, in practice it is seldom possible to see the influence of only one factor. Do you remember how I managed to simulate a model of low speed moisture evaporation influence? I represent to you PICTURES 022 and 023.

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Such mushrooms have grown after first flush fructification synchronization. Some druses "shot" before all and began their growth at the level of CO2 decreasing from 1 500 ppm to 1000 ppm, air humidity around 90 % and at the minimal air motion. 12. "TALKATIVE" MUSHROOMS. Can mushrooms tell us about the history of climate changes in a growing room? Certainly, they can. It is only necessary to study carefully the real history of the deviations in normal fruit body development and to gain the experience. And it is possible only with scrupulous writing of technological climatic documentation and supply of devices that give authentic indications. Recently I received a very rare opportunity to trace the history of ugly fruit bodies formation, see PICTURE 024.

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The climatic history of the given PICTURE has been restored owing to the following factors: - archiving of temperature and air humidity indices in the growing room - the mechanical engineer wrote down his actions in the note-book, - the workers did not hide their actions and honestly recollected all that had happened. The desert of the farm’s director should be noted as he managed to create such a friendly atmosphere in the collective. It is necessary to point out a merit of the director, who managed to create a friendly atmosphere in the collective. So: Once upon a time there grew mushrooms of trade quality of the strain NК-35… The workers of agricultural sector thought that there was too much vacuum in the growing room. They consulted with each other and switched off exhaust fans. It is possible to consider confidently that concentration of CO2 has increased intensively. Air humidity has increased from 83 up to 86 %. See site 1 on PICTURE 024. The mushrooms began to reach all-out for fresh air. Many did not sustain this race … The others managed to escape forward and continued to stretch out, losing their last energy. See site 2 on the same PICTURE. People saw that something wrong happened in the room. They consulted with each other again and switched on the exhaust fans again. But thus they reduced the fan speed of the input system and completely closed the recirculation damper. I.e. they considerably reduced air motion speed in the growing room on the background of a little СО2 concentration reduction. The attributes of insufficient moisture evaporation from fruit bodies became prevailing. See site 3 on PICTURE 024. Before my arrival with CO2 measuring device, the experts have lowered productivity of ventilation system having reduced the air motion speed. But thus they have lowered the temperature in the room for almost 2 °С. The caps of survived mushrooms started to develop with attributes of insufficient evaporation at CO2 level near 1 000 ppm. See site 4 on PICTURE 024.

13. EXPERIENCE OR DEVICES? And now I am such a clever and skilled expert able to define without any devices by the appearance of mushrooms what exactly is wrong in the growing room? Wake up!

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The PICTURE was taken at the same time in the same growing room as PICTURE 024. But it is not a strain NК-35, but K12. The same picture is all over the room. We can speculate that same concentration of CO2 forces NК-35 to stretch the stalk all-out, and K12, conversely, to stop its growth. Thus the gentle fleshy stalk of K12 becomes rigid as though wooden. So must we now develop a complex of trouble shootings for every strain? THE SECOND STORY. In the growing room at the stage of fructification there are one-age substrate parties of pleurotus strains K12 and Chinese Black. (In February, 2006 Nikolay Semenkov, the owner of the big pleurotus farm in Millerovo city, Rostov region, kindly presented to me two packs of mycelium Chinese Black. The mycelium was transferred to the laboratory of “Biotechnologiya”, Donetsk. Now the strain is put on the industrial test) The operator committed a short-term mistake - he raised the concentration of CO2 up to 1 000 ppm and raised relative humidity to the maximum. Here is what appeared two days later. PICTURES 026 - K12. PICTURE 027 - Chinese Black.

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THE THIRD STORY. I would like to draw your attention to three more PICTURES. See PICTURES 028, 029 and 030.

On all the pictures there is a strain A 3000. All the pictures were taken within one month period on the same farm in the similar growing rooms. All the pictures show a very close picture of fruit bodies’ damage. But here are the reasons … PICTURE 028. After 3-days long climate adjustments in 6 growing rooms with each capacity of 55 tons of substrate the technologist went home. At 8 o'clock the 3hours long check of boilers performance on maximum conditions was begun. But nobody managed to check if the humidification system copes with the increased air temperature. PICTURE 029. Late in the evening the entrusted representative of director arrives to the farm. It seemed to him that the temperature and the concentration of СО2 decrease too slow in the growing room. (We fulfilled synchronization of fructification by smooth reduction of carbonic gas concentration – see earlier

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mentioned article about measuring СО2). He personally opened delivery of fresh cold air. The operator noticed this error in 2 hours … PICTURE 030. The visitors arrived to the farm. With a foreigner! Politically correct employee ran through the growing rooms before representative’s delegation and switched off humidification systems so that condensate did not drop on the head of anybody. And then he forgot to switch it on again in one of the rooms with 55 tons of a substrate. Humidification did not work less than hour … So in three absolutely different ways we received undistinguishable damages of fruit bodies. THE FOURTH STORY. April, 2006. The seminar in Chernigov. I have finished my presentation. In the end I showed pictures of cyclic daily deviations in the fruit bodies formation. The reason was in daily increase of CO2 level in the growing room for 110 tons of substrate up to 1 000 - 1 1000 ppm for 5 - 6 hours during the work of pickers. The reason was insufficient productivity of ventilation system. I went out to the corridor to have a smoke. I left the disk with the pictures on the table. When I came back I was bewildered. Vladimir Matershev was commenting on my pictures and was absolutely mistaking! When I looked better I saw that they were not my pictures! And the reasons were opposite!!! The input ventilation of the growing room was "locked" – the power of exhaust fans had been calculated incorrectly. And the mushrooms have an opportunity to “breath” only during the work of pickers. The workers constantly open the doors and take out collected mushrooms in one box all day long. Yes, correct diagnosis has been found out. And if it was not he - Vladimir Matershev? In fact the character of damages in both cases was impossible to distinguish!

13. A BLUE MUSHROOM November, 2006. I was invited to the agricultural sector “Mokrinskiy” in Nizhegorodskaya region with request to eliminate the reasons of substrate wastes (sterile technology) and adjust the climate in the mushroom growing room. I saw the picture shown on PICTURE 017. Above I described in detail which measures have been taken to correct the situation. In short, in 3 days over all the room we received approximately the following picture– see PICTURE 031.

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The last day of work there was a festal occasion – Aleksey Tishenkov visited us. It was a holiday of communication from the early morning to the midnight! And there was a moment when the technologist of agricultural sector wondered: “Why have most of the mushrooms in the growing room become blue?” As it turned out, I was unprepared to answer this question. Of course, earlier I saw this phenomenon from time to time but it didn’t cause my alarm. Aleksey supposed that mushroom turns blue after quite a rapid drop in temperature. He might be right. I begin paying attention to the cases of blue pleurotus. I offer you the results of my observations.

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the young pleurotus joint of the strain К 12 is presented to your attention At night we couldn’t maintain the temperature in the growing room and it decreased by 6 °C. PICTURE 034

shows how the young mushrooms of the strain K12 turned blue. If to look closely at them, one can see that the mushrooms reacted differently. There are blue, yellow and blue mushrooms with brown spots. The picture was taken in 24 hours after cooling.

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Chinese Black had the evener blue strain. See PICTURE 035.

And quick-growing strains Russian M 5 and 959 of LeChampion firm didn’t wish to blue. See PICTURES 036 and 037 accordingly.

Let’s consider how the affected mushrooms of the strain K12 have been evolving. The mushrooms which turned brown after the cold shock have stopped in growing soon. Gradually they turned brown, perished…See PICTURE 038.

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So, we may draw a preliminary conclusion: if a mushroom became brown during a cold shock – it is doomed. Conversely, a blue mushroom has chances to survive. Another joint of the strain K12 which was less damaged during the cooling, has been developing in the way shown on PICTURE 039.

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It is now obvious that the blue mushrooms are also considerably behind in the growth from those which had been very small earlier and hadn’t almost be seen under the larger and more developed but blue fruit bodies. It is interesting how Chinese Black feels now. See PICTURE 040. It has become blue but it keeps on growing forthright. M 5 (PICTURE 041) and 959 from LeChampion (PICTURE 041-A) almost didn’t notice the cold chock.

Summer species seem to be much more stable to the rapid drop in temperature. However, they are more demanding to the increase of CO2 concentration and require more powerful ventilation systems. The mushroom is frailer and causes a lot of problems when coming into the market. Would it seem that we should work only with Chinese Black? As you can’t at it! And at this time my familiar mushroom grower from Ochakov called me. At the end of the continuous conversation it developed that as a result of cooling the growing room for 10-11°C over the night almost all mushrooms of Chinese Black strain fist turned blue, then browned and perished. Any new cultured organism with high genetic potential and crop, either it is a variety of wheat or breed of pigs, or mushroom strain, is more sensitive to the unfavorable environment or deceases than its natural archetype. If we want to realize the maximum potential of this strain, any rapid changes in climate are undesirable! And what should we do if we are to cool growing rooms throughout fructification? 14. ALGORITHMS OF GROWING ROOM COOLING I think many mushroom growers still remember the severe winter of the previous year. For a long time we were frightened by biting frosts, and there were no frosts yet… And then they broke out. In Kherson in the South of Ukraine during 1,5-2 weeks the temperature ranged from 18 to 28 °C. Twice I recorded 32°C outdoors!

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It was an interesting time. The frosts were unavoidable. I had 8 growing rooms with 55 tons of pleurotus substrate with poor insulation and low-power heating boiler. And I had time for thinking. I offer you the algorithms of growing room cooling which I developed last winter and tested for 2 seasons. They are: 1. ATTENTION! Input ventilation in a growing room is allowed to turn off only if temperature falls to 8°C and less in the growing room. 2. Previously the following mode should be set in a growing room: temperature less than 14°C, CO2 from 700 to 800 ppm, Rh more than 85%. Parameters should be maintained in the constant mode for at least 6 hours for substrate temperature stabilization. 3. Decrease heat supply in a conditioner calorifer. 4. During the drop in temperature and CO2 concentration in a growing room close softly fresh air damper in ventilation system. Keep the concentration of CO2 in the range of 700-800 ppm. 5. Temperature descent rate should be 1°C per 2 hours. 6. While temperature drops to 6-8°C in a growing room, the concentration of CO2 should be reduced to 600-650ppm by changing the fraction of fresh air in the ventilation system. 7. Maintain the temperature and CO2 in this mode in a growing room at least for 6 hours. 8. Turn off the system of input ventilation. A posteriori, I can say that in those growing rooms where I worked, natural draughts at such a temperature are quite enough to keep mushrooms and substrate blocks in good condition at least for 5-6 days. And during the reconstruction of ventilation system on Vitaliy Vorona’s farm the ventilation in the cold growing room haven’t been working for 8 days. The result of well-timed and atraumatic cooling of 8 mentioned growing rooms is: - the usual cycles of fructification increased by more than 10 days. - the crop of the cold substrate lots in 2 flushes dropped ONLY from 19-20% to 18%. - we DIDN’T WASTE any kg of mushrooms! Such a deep cooling method is necessary when the reconstruction of ventilation systems is planned, when capacity of heating systems isn’t enough during the frost, when… 15. PRIMORDIUMS HAVE BEEN DROWNED! The same winter of 2005-2006. Nikolay Semenkov called me 2 or 3 times, he is the owner and changeless director of the biggest pleurotus farm in the South of Russia in Millerovo city, Rostov region. Nikolay was very anxious of the rapid drop in harvesting and yield on his farm that winter. His technologists made a preliminary diagnosis that it was bacteriosis of fruit bodies. And they tried to cure of exactly this bacteriosis. I am very partial to this farm. In 2002 I spent 8 months of intensive work there and gave it a piece of my heart. So I do have the same warm memories about Nikolay Semenkov. So, in February, 2006, I could finally visit Millerovo for several days.

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And I saw the following picture in the growing rooms. See PICTURE 042.

The reason was: - Low fresh-air intakes. It was very cold and windless winter. Fresh-air intake captures a waste warm wet air, and air pipes frost inside! - For ice defrosting the ventilation is turned off 2-3 times per day for 30-50 minutes. - During this period the temperature in the growing rooms decreases by 3-5°C. Very cold winter! - Trying to warm the substrate and fruit bodies as quickly as possible, operators fan a warm wet air in the growing rooms. - The film of condensate is formed on the surface of the fruit bodies and primordiums. Mature mushrooms survive some how. But primordiums and young mushrooms…However, look at the PICTURE 042 once more. - Primordiums and young fruit bodies perished. The secondary infection develops on the dead biomass. By the way, in this case we had a mold not bacterial affection. In the incident described above we managed to improve the situation by decreasing air humidity fanned to the growing rooms during their warm-up, as well as by decreasing the speed of warm-up in the growing rooms. The last remedy was to design fresh-air intakes in compliance with the draft design of far back as 2002. So, primordiums and young mushrooms perish, when they are drowned in condensate. But I can’t take pictures of these primordiums anyhow. I take this picture to heart and every time I forgot about my camera. And only afterwards, when you manage to save (or not to save) primordiums, you recall about illustrations for magazine. Anyhow, the consequents of such a condensate form are available to show. See PICTURE 043.

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This is the way primordiums of K12 look next day after the film of condensate was formed on them. The strain 930 from LeChampion suffered much less. See PICTURE 044.

The picture is taken in 2 days after the condensate “injury”. M5 doesn’t react, as it seems to me, on such trivia as condensate on primordiums. Chinese Black. Well, I am not lucky – I failed to find primordiums drawn in condensate. So I had to experiment. I took a substrate block from the lot with big primordiums. See PICTURE 045.

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And during a morning I sprayed water three times over a great “knur” of primordiums, protecting the neighbor one not to wet it. 7 days passed. The result is on PICTURE 046.

I think, no comments. So, condensate on primordiums is harmful for winter species. But it is necessary to warm growing rooms after their cooling. And it is terrible to “catch” dew point on the surface of young fruit bodies. Let’s pass to the algorithm of the safe heating of a mushroom growing room. 16. ALGORITHM OF GROWING ROOM HEATING AFTER COOLING 1. Make sure water and/or vapor delivery to an air damping room is turned off. 2. Make sure fresh and recirculation air dampers of an air conditioner arrangement are completely closed.

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3. Turn on a fan of an air conditioner arrangement. Open fluently a recirculation air damper until it is completely opened. Plastic air pipes are necessary to be filled gradually. 4. Keep a growing room in such a mode for at least an hour. It is necessary to stabilize the temperature of a substrate and fruit bodies all over a growing room. 5. Open slightly a heat medium delivery to a conditioner. 6. Start delivering water\vapour to an air damping room of a conditioner arrangement only after decrease in air humidity to 85% in a growing room. 7. Maintain temperature in a duct neither more than 3°C higher than in a growing room. 8. When increasing in CO2 concentration higher than 950 ppm in a growing room, start opening a fresh air damper very fluently and gradually. 9. During a growing room warm-up maintain CO2 concentration at the level of 900-950 ppm. 10. When the temperature is 14 °C in a growing room, stop its warm-up. 11. Maintain Rh=85 – 94%, temperature = 14-15°C in a growing room at least for 6 hours. During this procedure gradually decrease CO2 concentration to 800 – 850 ppm by increasing the fraction of fresh air in an airconditioning system. If the capacity of an air-conditioning system allows – don’t touch a recirculation air damper but keep it on state. If there are substrate blocks with primordiums or young mushrooms in a growing room, there is a danger to drawn primordiums in condensate when the warm wet air contacts with the cold substrate. In this case it is necessary to place a temperature sensor or thermometer under the film (between the film and substrate) of one of such blocks. The growing room should be warmed up according to the algorithm described above. BUT the difference between air temperature in the duct and under the film of the substrate block shouldn’t exceed 1°C. Control condensate on the surface of primordiums. Curiously enough, but such a precise and careful heating mode results in very quick warm up of a growing room if there are young substrate blocks in fructification stage there. HOW MUCH DOES A MISTAKE COST? A small mushroom farm. Proceeding from its cultivation cycles and crop yield, there is a desire to predict a harvest of 9 - 10 tons of mushroom per month. But 9 tons per month is like a bewitched number! Every time some fail happens! I give you the description of such a fail in December, 2006. From the very beginning of the month the mushroom was picked according to the schedule 9 tons per month. See PICTURE 050.

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At night on 15th of December (on the chart it is marked by the thick black funereal letter A) “smart” operator closed the fresh air damper, as well as the recirculation air damper, and went to bed. The temperature decreased by 6°C, the concentration of CO2 increased to 1000-1100 ppm and air relative humidity fell outside the range. And in the morning he tried immediately to warm up the growing room. This situation was described above in this article. You can see once more the defects of the mature fruit bodies of the strains K12 and Chinese Black on PICTURES 026 and 027. A trifle, isn’t it? And this is how most primordiums of the strain K12 look next morning. See PICTURE 047. And another picture in 2 days…See PICTURE 048.

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And even young mushrooms of the “not drown” Chinese Black stood it with difficulty. See PICTURE 049.

The picture is taken in 6 days after climatic shock. From the chart of mushroom crop (let’s return to PICTURE 050 once more) one can suppose that the waste from one operator’s mistake was at least 1 ton of mushrooms. It is a little more than 10% of the total month crop! It is very painful to lose $2,000 of income per month for a small mushroom farm! I ask you to recall the story with bad mushrooms on the farm of Nikolay Semenkov. According to the figures of his technologists, the farm lost about $90,000 for the last 2-3 winter months! However, Nikolay himself declared a little less figure.

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It is very painful! 18. WHAT IS NECESSARY? So, what is vitally necessary right now for your manufacture: devices or a talented technologist with long experience and developed intuition? It seems to me, devices are more available, cheaper and easier-to-use. And Aleksey Prisyazhnyuk, though he agrees completely with my arguments, insists: “Both are necessary!� But he already has the complement of devices. And now he is busy with monitoring climatic parameters all over his farm. You wonder if there is a return? It is better to ask about it Aleksey himself. See PICTURE 051.

13. A GREAT REQUEST. Dear colleagues, once again I offer you: Please reread and analyse this article and applied illustrations. And if you do not agree with something and can give me a REASON of your objection, please write to me. My e-mails: and I look forward to your letters. Together we can discover something useful to all of us. Do you agree? 14. INSTEAD OF CONCLUSIONS. Dear colleagues, skilled and those, who only think of starting the mushroom business. Once again I wish to draw your attention, that working on the farms with competently designed system of air distribution in mushroom growing rooms and well prepared ventilation system I simply DID NOT MEET many sores and defects of pleurotus fruit bodies!

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So, even competent mushroom growers often talk about «bacteriosis» of fruit bodies connected with mycelium quality or very seldom with bad quality of their substrate. In my practice only 3 or 4 times during the last 10 years of work I met deviations in pleurotus fruit bodies development connected with concrete parties of mycelium. (See my article « Methods of work with mycelium.) Only 1 time I have met ugly fruit bodies connected with the party sunflower husks. And no more than 5 or 6 times I observed deviations in fruit bodies development from healed INFECTED substrate blocks. All other cases, and there are more than a hundred of them, came from disorders of optimum climatic conditions!!! Even during transition period I NEVER saw the legendary autumn or spring destruction of fruit bodies in rooms with competently designed and carefully made system of air distribution, compatible with air preparation system. And in the growing rooms with the errors made at the stage of design I saw it already FOUR times during the last autumn. And in fact the destruction of mushrooms is someone's tragedy. It is a possible and very real crash of someone's family’s well-being. And I can’t stand blockhead consultants who offer their "fantastic projects" of growing rooms to clients. And in fact they are not only private persons, but also serious and advertised organizations. You have decided to occupy yourself with cultivation of mushrooms? You have decided to deposit your or loan money? I see the only way for your future protection. Find the most meticulous information about your potential designer or technologist. You should necessarily familiarize with the projects he made before. Spend some money for development of the PROFESSIONAL outline sketch. If your technologist or consultant says that payback time of the project is a year or two – you should urgently change him. Change both a project and consultant. Mushroom business is a difficult business. And "freebie" here, as a rule, is superfluous. Unless, one of the partners "abandons" the others and becomes the first. But this is not the concern of the article’s theme any more … So, at first: - professional outline sketch - market survey And only then make your final decision.

Victor V. Yakushenko