NL2008703C2 - Harvesting of mushrooms. - Google Patents

Description

Harvesting of mushrooms DESCRIPTION

TECHNICAL FIELD OF THE INVENTION

5 The present invention relates to mushroom cultivation and provides an apparatus and method that improve the harvesting process. It further provides an apparatus and method with increased yield. Furthermore, the apparatus is very accessible to people harvesting mushrooms. As a consequence yield per 10 unit time is increased. Further, physical complaints relating to harvesting of mushrooms are decreased.

BACKGROUND OF THE INVENTION

Mushroom growth has been studied during centuries.

Many species of mushrooms seemingly appear overnight, 15 growing or expanding rapidly. In actuality all species of mushrooms take several days to form primordial mushroom fruit bodies, though they do expand rapidly by the absorption of fluids .

Most mushrooms that are sold in supermarkets have 20 been commercially grown on mushroom farms. The most popular of these, Agaricus bisporus, is generally considered safe for most people to eat because it is grown in controlled, sterilized environments, though some individuals do not tolerate it well. Several varieties of A. bisporus are grown commercially, 25 including whites, criminy, and portobello. Other cultivated species now available at many grocers include shiitake, mai-take or hen-of-the-woods, oyster, and enoki.

White mushrooms, like all mushrooms, grow from microscopic spores, not seeds. Plant-like organisms growing from 30 spores are called fungi.

Because mushrooms have no chlorophyll, they must get all their nutrients from organic matter in their growing medium. The medium-called compost is scientifically formulated of various materials such as straw, corn cobs, cotton seed and 35 cocoa seed hulls, gypsum and nitrogen supplements. Preparing the compost takes one to two weeks. Then it is pasteurized and placed in large trays or beds.

Next the spawn is worked into the compost and the growing takes place in specially constructed houses, where the 40 farmers can regulate crucial aspects as temperature and 2 humidity.

In two to three weeks, the compost becomes filled with the root structure of the mushroom, a network of lacy white filaments called mycelium. At that point, a layer of 5 pasteurized peat moss is spread over the compost. The temperature of the compost and the humidity of the room must be carefully controlled in order for the mycelium to develop fully. Eventually, tiny white protrusions form on the mycelium and push up through the surface of the peat moss. Farmers call 10 this pinning. The pins continue to grow, becoming the mushroom caps, which are actually the fruit of the plant, just as a tomato is the fruit of a tomato plant. It takes to 25 days to produce mature mushrooms after the peat moss is applied. Size is no indication of maturity in mushrooms. Perfectly ripe ones 15 vary from small buttons to large caps.

Each crop is harvested over a period of several weeks. Typically two or three crops are harvested. Then the compost does not generate enough crop anymore; it may be regarded as "exhausted". Then the house is emptied and steam-20 sterilized before the process begins again. Harvested mushrooms are set in carts, refrigerated and then packaged and shipped quickly to supermarkets, food processors and restaurants. The entire process from the time the farmer starts preparing the compost until the mushrooms are harvested and 25 shipped to market takes about two to three months.

Edible mushrooms are used extensively in cooking.

. Various species are mentioned below.

Criminy mushrooms are grown and harvested in the same manner as the white mushroom. Portobello mushrooms are also 30 grown like the white mushrooms. Oyster mushrooms, like other mushrooms, are grown in mushroom houses but they require a bit more humidity and fresh air than the white variety. Shiitake mushrooms were originally cultivated on natural oak logs, a process which took two to four years before the mycelium colo-35 nized the wood sufficiently to produce fruiting. Now, however, oak sawdust is packed into poly bags, sterilized, inoculated with spawn and placed in environmentally controlled rooms. For Enoki mushrooms, beach mushrooms and maitake mushrooms even more complex procedures are used, requiring specific control 40 of e.g. temperature, carbon dioxide content, and humidity, as 3 well as specific specially prepared substrate material.

The main costs involved in the production of mushrooms includes compost production, harvesting and packaging. The harvesting of mushroom may still be done manually. Mush-5 room farmers in addition to basic procedures use their own techniques to make the process convenient, but still it is very laborious, time consuming and expensive in terms of production cost. Thus, the involvement of manual labor increases the production cost and also increases the chances of poten-10 tial contamination. This creates additional maintenance problems .

Although there are some mechanical devices and methods for mushroom harvesting, these generally involve expensive technology i.e. video camera, mechanical platforms and other 15 devices. Further, albeit chances of contamination by physically not touching the mushrooms are minimized, which in turn also enhances the shelf life, mechanically picking of mushrooms results in a much lesser quality of the product. As such, the mushrooms can only be used for directly processing 20 the mushrooms into food products, like conservatives.

Considerable effort has been made to reduce the costs involved in production it self, but less attention has been paid towards reducing costs in harvesting, and in optimizing yield in terms of kilogram mushroom per unit area.

25 Thus, disadvantages of the prior art method are amongst others laborious and therefore expensive methods of harvesting, and limited yield in terms of kilograms mushroom per unit area and in terms of kilogram mushrooms per unit compost .

30 A previously filed Dutch patent application NL2005616 of the present inventors•relates to an apparatus and method of harvesting mushrooms. After extensive experimentation it has been found that an embodiment disclosed therein could be optimized further, e.g. in terms of yield (kg) mushrooms per 35 square meter, size of mushrooms being harvested, use of raw material, hygienic aspects, stability a system used, time lapsed between start and first or subsequent crop harvesting, ease of harvesting, etc.

A German patent application DE 43 02 273 Cl recites a 40 circular system comprising a compost layer and a non- 4 penetrable material directly surrounding said compost. The material can not be accessed by mycelium. The system is regarded to be relatively complex. In order to control temperature and moisture further means are provided thereto. It is noted that 5 as far as known the system has not been put into practice, possibly because the system makes it very difficult to provide optimal growth conditions for mushrooms, or at least over a prolonged period of time; in other words it is no commercial success. A reason thereto is that it is not understood how 10 e.g. moisture, temperature, amount of air, evaporation, especially that of compost, can be controlled in practice. Further it seems at least unlikely mushrooms will sprout, as mycelium is expected to die beforehand, as penetration will amongst others occur to slow. The system does not comprise a covering 15 layer fully penetrable for mycelium.

US 3,286,398 recites a system comprising a casing surrounding compost. Mushrooms seem to be harvested at sides of slats (left and right). Similar disadvantages as with the above German patent seem to occur.

20 Also there is a need to control size and amount of mushrooms. Further, handling is preferably limited to a minimum. Also an apparatus should function in a hygienic manner. Preferably the amount of compost and/or covering layer, also in relation to each other, should be minimized.

25 In view of a prolonged use, e.g. at least three crops should be harvested, optimal grow conditions need to be provided, thereby providing optimal yields.

Thus there still is a need for improved methods and tools for harvesting mushrooms, which methods and tools over-30 come one or more of the above disadvantages, while at the same time not jeopardizing other favourable aspects of harvesting. SUMMARY OF THE INVENTION

The present invention relates to an apparatus for harvesting mushrooms according to claim 1 and a method accord-35 ing to claim 8. It is noted that the present invention has only become available after prolonged experimentation, identifying further non-trivial boundary conditions, e.g. in view of the aforementioned Dutch application.

Therein the top and bottom layer have a relative open 40 structure, allowing mycelium to pass through, providing water 5 and air thereto. The amount of air is from 15-40%, the amount of moisture is from 10-40%, and the amount of soil constituent is from 30-60%, relative to a total volume. The soil constituent may comprise 0-100% organic material, and 0-100% inorganic 5 material. The layers are preferably pasteurized, in order to provide a largely pristine medium. Preferably the soil constituent is peat or the like. It is preferred to provide a relatively open structure, i.c. a relative large amount of air and/or moisture.

10 The inner layer preferably comprises a material such as compost, capable of comprising mycelium therein.

The top and bottom covering layer are directly accessible for harvesting, such as in a casing, the casing being substantially open at a bottom thereof, the bottom comprising a sup-15 port, the casing being fully open at a top side thereof, and the casing being closed at sides thereof, therewith providing structural integrity.

A total stack of top and bottom covering layer and inner layer is from 10-30 cm thick, such as 15-25 cm.

20 The compost at casing is controlled, e.g. in terms of amount of mycelium per unit area and thickness of the layers. Also anastomosis is controlled as well, wherein anastomosis is somewhat less in the bottom covering layer, i.e. a more open structure in terms of mycelium is provided. Therewith it has 25 been found by inventors advantages of the invention are obtained.

Though higher yields could be obtained present inventors have limited the (extra) yield of the bottom side to 8-12 kg/m2, whereas the top side provides 25-35 kg/m2, both numbers 30 for the first crop. It has been found experimentally that providing a symmetrical stack of layers, i.e. top and bottom covering layer are of equal thickness and of equal composition, does not provide optimal results, e.g. in terms of total yield over 1 or more corps, accessibility, working conditions, qual-35 ity of mushrooms, etc.

By controlling parameters the size of mushrooms on the bottom side is somewhat larger, from 10-100% larger (in terms of weight or size (diameter of head)). Unexpectedly parameters such as anastomosis, thickness of the bottom covering 40 layer, temperature, and moisture play a role in providing lar- 6 ger mushrooms .

Picking or harvesting is performed in upside down position. Such requires some adjustments in view of picking conditions, e.g. in view of human health and working conditions.

5 On the other hand it has been found experimentally that picking of a mushroom itself can be performed easier by only slightly touching or tickling the mushroom, which "automatically" falls in a hand of a picker. The mushrooms are also surprisingly cleaner than on the top side. Unexpectedly the 10 harvesting of mushrooms does not contaminate optional underlying trays; as mentioned above, harvesting is even cleaner as on the top side. As such high quality mushrooms are obtained.

By providing an open environment on both a top and bottom side of the present apparatus otherwise comparable 15 mushrooms are obtained, e.g. in view of appearance, being perfectly white in case of Agaricus bisporus, having a relative high amount of moisture, good taste, good firmness, almost circular cap, etc.

The amount of moisture, humidity and temperature, and 20 variation therein as required, can be controlled by measures known per se. There is no need for extra measures and/or complex systems. In other words, it has been found that by controlling the parameters mentioned, good (extra) yields can be obtained. The growth of mushrooms is e.g. in view of the cited 25 prior art much better, and also in view of a standard onesided tray. However, when providing water it is preferred to provide such an amount that only some initial dripping on the bottom side occurs. It has been found that surprisingly the initial dripping liquid is still relatively clean, i.e. mainly 30 comprising water. As such optional underlying trays (or casings) remain in hygienic conditions.

Surprisingly only a relatively open support on the bottom side can be provided. Such a relatively open support is sufficient in view of the present invention.

35 The present invention may further relate to harvest ing using a container, that is especially the top side may be provided with containers comprising openings therein. As a consequence the present invention provides a longer shelf life; due to the persistent conditions of moisture, tempera-40 ture and inside of the bed, which remains the same even after 7 mushrooms are detached. This technique of mushroom cultivation also enhances the shelf life by minimizing the level of contamination due to direct human touch and minimum exposure to the outer environment. Thus mushrooms stay fresh for a longer 5 period of time.

The present method will significantly reduce the cost of mushroom production by improving the process of harvesting and increasing the yield of mushrooms per unit volume of compost used. Nowadays, using prior art methods, mushroom pickers 10 can harvest about 20-30 kg mushrooms per hour, depending on the size and type of mushrooms. With the present method a mushroom picker can harvest 25-35 kg per hour, that is significantly more than the prior art methods.

Further, the yield in terms of kg mushroom per unit 15 volume of compost is increased (e.g. from 30 kg/m2 to 45 kg/m2, or 40-60% extra), compared to e.g. use of a tray wherein only one side is used. As a consequence the costs of harvesting are reduced by 10%-33%, most likely by 20% or more.

Despite the apparent advantages of the present inven-20 tion, mushroom harvesting has not been developed accordingly. Further, in view of the huge market potential and turnover of mushroom, the present development is of the utmost importance to mushroom harvesting. The present combination of measures taken is, however, not disclosed in the prior art, nor is 25 there a suggestion towards these measures.

Further, the present invention provides newly developed and improved control of temperature and humidity of layers used. Such is also favorable for mushroom growth. Temperature and humidity are amongst others better controlled and 30 more stable. Further, it is very easy to adapt humidity by spraying or dripping of liquid, e.g. water. It has been found that spraying or dripping can be stopped when a bottom side starts showing droplets on a surface area thereof. A further advantage is that humidity or liquid can easily enter and 35 leave the present apparatus. Such is amongst others not the case in various prior art apparatuses.

Thus the present method provides a cheap and fast method of harvesting, and increased yields, overcoming disadvantages of the prior art.

40 Further advantages are mentioned above and below.

8

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect the present invention relates to an apparatus for harvesting mushrooms, according to claim 1.

In an example the present apparatus further comprises 5 a bottom support layer underneath the bottom covering layer, the bottom support layer comprising a substantially water tight material, such as a polymer, a natural or artificial rubber and/or wherein the top covering layer is open to the environment.

10 The bottom support layer is to some extent open to mycelium, in order to allow pinning. It has been found that, amongst others, with such a layer, size, shape, amount and quality of mushrooms can be influenced. On the other hand the top covering layer is best left open and in full interaction 15 with the environment, such as by exchanging air and moisture.

In an example of the present apparatus the bottom support layer comprises holes, the holes having an area of 0.1-9 cm2, preferably from 0.25-5 cm2, more preferably 0.5-4 cm2, such as 1-3 cm2, and/or wherein a density of holes is 20 100-2500/m2, preferably 250-1000/m2, more preferably 400- 600/m2, and/or wherein the holes are spaced in a regular pattern, such as trigonal, square, diamond, hexagonal and octagonal. It has been found that holes are preferably not too large, as then control of size, amount, etc. of mushrooms is 25 limited. Too small openings mainly limit a yield of the bottom side, as well as control thereof. The best results are obtained with holes having an area of about 2 cm2. It has also been identified experimentally that preferably a density of holes is not too high, and not to small either, in view of the 30 above. The best results are obtained with a density of about 500 holes/m2. The spacing of the holes preferably follows a regular pattern, thereby allowing a pre-determined space in between holes, e.g. in view of providing optimal growth conditions, and in view of the above.

35 In an example of the present apparatus a thickness of the bottom covering layer is 0.2-0.8 times a thickness of a top layer, preferably 0.3-0.6 times, such as 0.4-0.5 times, and/or wherein a thickness of the bottom covering layer is from 1.5-7 cm, such as 2-4 cm. Such seems somewhat contra-40 intuitive, as e.g. a bottom layer is expected to fulfill other 9 functions as well, such as support. Also it would be expected that by providing a thinner layer a larger yield could be obtained, as a surface is somewhat closer to the inner layer comprising compost. It has been found experimentally that e.g.

5 in view of the present objectives a thinner bottom covering layer provides better results. It has been found that preferably a thickness of a bottom layer relates to a thickness of a top layer. Therewith optimal results are obtained. Further also absolute numbers for a preferred thickness could be ob-10 tained through experimentation. A too thin, layer does e.g. not provide sufficient yield, nor good quality, whereas a too thick layer does e.g. not provide larger mushrooms. Good results were obtained with a thickness of 3 cm.

In an example of the present apparatus an initial 15 amount of spawn at compost at casing is 0.7-1.5 kg/m2 top covering layer, preferably 0.85-1.25 kg/m2 and/or wherein an initial amount of spawn at compost at casing is 0.45-1,0 kg/m2 bottom covering layer, preferably 0.65-0.9 kg/m2, and/or wherein a ratio between an initial amount of spawn at compost 20 at casing in the top covering layer/bottom covering layer is 1.1-2, preferably 1.2-1.5, such as 1.25-1.4, and/or wherein a density of the top covering layer is 600-1100 kg/m3, preferably 700-900 kg/m3, and/or wherein a density of the bottom covering layer is 800-1400 kg/m3, preferably 900-1200 kg/m3. It 25 has been found experimentally that too much or too little spawn e.g. limits the yield, provides poor guality mushrooms, etc. Good results in view of the present objective were obtained with 1,0 kg/m2 for the top covering layer and 0,8 kg/m2 for the bottom covering layer. Surprisingly not only the abso-30 lute amount is relevant, but also relative amounts. It has been found that in order to optimize parameters in view of the present objectives the best results were obtained with a ratio of about 1.25 (top/bottom). It has also been found experimentally that the density of the top and bottom covering layer 35 are preferably not the same. In order to control parameters, such as moisture, yield, size, hygiene, and temperature, adequately the density of the bottom covering layer is preferably larger than that of the top covering layer, such as 1000 kg/m3 and 800 kg/m3, respectively. Despite an optional bottom sup-40 port layer, relevant for amongst others yield, moisture and 10 size, it is still preferred to control the above parameters by-providing a denser bottom covering layer.

In an example of the present apparatus comprises 1-7 trays, such as 2-6 trays, each tray comprising a sequence of 5 layers. In view of control of e.g. humidity, temperature, etc., but also in view of costs and labor conditions, more trays are preferred, such as 5-10 trays. However, to many trays make control difficult as well as working conditions less acceptable. Further too many trays increase a risk of 10 contamination, especially of underlying trays. Therefore 5-7 trays are preferred. The trays are preferably provided with a means for moving the trays upwards and downwards.

In an example of the present apparatus comprises a supporting gauze, such as a chicken wire, the gauze preferably 15 having openings with an area of 1-16 cm2, more preferably 2-10 cm2, such as 4-6 cm2, wherein the gauze preferably is located underneath the bottom covering layer, more preferably underneath the bottom support layer, and/or wherein the apparatus comprises supporting means, such as bars. In order to increase 20 e.g. yield the area is relatively high such as 4-6 cm2. In order to provide strength the area is preferably small. A good balance has been found with a gauze with an area of about 5 cm2 .

The gauze or mesh has opening large enough to allow 25 growth of mushrooms, but small enough to maintain the layers in place, such as from 2 cm by 2 cm to cm by cm, e.g. 3 cm by 3 cm to 5 cm by 5 cm. Further the gauze or mesh is stiff or rigid enough in order not to bend, e.g. made of a metal, or a strong fibre, such as Dyneema. As such also the inner and cov-30 ering layers remain in good contact with each other. The gauze or mesh preferably does not bend more than about 2 cm per meter in view of the present objectives. Further, the material chosen for the gauze or mesh needs to have a neutral character for mushrooms. In an example it does not contain fungicide.

35 Further, in an example it does not release chemical compounds or elements. In the present apparatus surprisingly a layer situated at the bottom remains in and provides better quality than a layer situated at the top.

An important difference with prior art methods is 40 that harvesting mushrooms is performed on trays, using two 11 sides thereof, i.e. harvesting two sides of the compost layer. Such trays have improved accessibility and provide significant higher yields.

The term "mushroom" is used herein to refer to any 5 type of mushroom, specifically edible and medicinal mushrooms. The term therefor includes the most familiar cultivated mushroom, Agaricus bisporus, and also includes other types of mushrooms, such as oyster mushrooms, criminy mushrooms, Porto-bello mushrooms and shiitake mushrooms, just to mention a few. 10 The Agaricus bisporus is the most important mushroom in terms of units of production. A preferred embodiment of the present invention is therefore specifically applicable to Agaricus bisporus.

The substrate may be spread out through a large pro-15 duction unit, as in prior art methods. Nowadays the substrate typically comprises one or more layers, typically a compost layer and a peat layer on top thereof, though some of the above mentioned mushrooms require specific other substrates and configurations. However, any other type of substrate is 20 envisaged, as long as the substrate is capable of producing mushrooms. The growth conditions per se are comparable to prior art methods. When mushrooms have reached a required size or age the containers can be harvested, either by hand or automatically. When the mushrooms are harvested they can be 25 stored in a cooled environment, or shipped. When the mushrooms have been harvested these are preferably directly shipped and placed on the market, being as fresh as possible. The present apparatus provides such direct action.

The width of a tray may vary from about 2 m to about 30 15 m, the height from about 50 cm to about 2 m, and the thickness from about 10-30 cm. A too large tray is difficult to ac cess, and is therefore not preferred. A too small tray is too laborious, and does not yield enough mushrooms. A tray is in an example further provided with a mechanism to allow better 35 access thereof, such as by opening and closing the tray and/or moving the tray upwards or downwards.

In an example the present the covering layer has a surface area of between 0.5 m2 and 250 m2, preferably between 1 m2 and 100 m2, more preferably between 3 m2 and 25 m2, such 40 as 5 or 6m2. The surface area, is taken as the area where 12 mushrooms grow and are harvested. It has been found that these areas are optimized in terms of yield, ease of access, ability to handle, ease or ability to fill and empty a tray, etc.

In a second aspect the present invention relates to a 5 method of harvesting mushrooms, comprising the steps of providing an apparatus according to the invention, growing mushrooms, and harvesting mushrooms. As such, mushrooms are allowed to grow during a period long enough to harvest them thereafter.

10 In an example in the method the mushrooms are se lected from the group comprising Agaricus species, such as Agaricus Bisporus, Agaricus brasiiliensis, Agaricus subrufes-cens, Agaricus Blazei (Murill) , Agaricus bitorquisf Pleurotus species, such as Pleurotus ostreatus, Pleurotus sapidus, Pleu-15 rotus citrinoplieatus, crimini mushroom, portobello mushroom, Lentinula edodes, Grifola frondosa, Agrocybe aegerita, Can-tharellus cibarius, Hericium erinaceum, and enoki (flammulina velutipes).

The invention is further detailed by the accompanying 20 figures and examples, which are exemplary and explanatory of nature and are not limiting the scope of the invention. To the person skilled in the art it may be clear that many variants, being obvious or not, may be conceivable falling within the scope of protection, defined by the present claims. Examples 25 of the invention may be combined.

DESCRIPTION OF THE DRAWINGS / FIGURES

The invention although described in detailed explanatory context may be best understood in conjunction with the accompanying figures and photographs.

30 Fig.1 shows a cross-section of an apparatus according to the invention.

Fig,2a-c show mushrooms growing on a bottom and top side of a present apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS 35 In figure 1 the example shown has a total surface area of about 5.4 m2. The size of the tray shown is somewhat large, e.g. about 3 meter by 1.2 meter. The thickness of the inner layer is about 15 cm, whereas the thickness of the top layer is about 12 cm, and the bottom layer about 6 cm.

40 In the present set-up a first yield (per m2) of 30 kg 13 mushrooms was obtained, a second yield of 21 kg and a third yield of 9 kg, whereas prior art apparatuses provide yields of 18 kg, 12 kg, and 5 kg respectively. Therefore the addition of a second layer has increased the yield with 12 kg, 9 kg, and 4 5 kg respectively, without using more compost. Clearly a second or extra though limited amount of peat is supplied.

Figure 1 shows a cross-section of an apparatus according to the invention. Therein mushrooms (220, 221) are grown on outside layers (210, 211). The outside layers are 10 covered with a gauze (240, 241). The inner layer comprising compost (230) is further shown. The apparatus relates to a rectangular tray, wherein the bottom, the top, and possibly front and back side of the inner layer are covered. It is noted that it is sometimes to difficult to access a front or 15 back side of a standard tray, in view of the construction thereof, i.e. having closed sides. In such as case the front and back side are not used for growing and harvesting mushrooms .

Figs. 2a-c show mushrooms growing on a top and bottom 20 side (up-side down). Both sides have in the example approximately equal yields, e.g, 30 kg/m2, except in fig. 2c wherein the bottom yield is limited intentionally.

Claims (9)

A device for harvesting mushrooms comprising from top to bottom: an upper cover layer comprising air, water and at least one soil component, an inner layer comprising a substrate, such as compost, the substrate comprising mycelium ,. a lower cover layer comprising air, moisture and at least one basic component, wherein during the production of the mycelium extends through the coating layers, the upper and lower layers being directly accessible for harvesting mushrooms. 2. Device as claimed in claim 1, further comprising a bottom support layer below the bottom cover layer, the bottom support layer comprising a substantially water-tight material, such as a polymer, a natural or artificial rubber and / or wherein the top cover layer is open to the environment. 3. Device as claimed in any of the foregoing claims, wherein the bottom support layer comprises holes with a surface area of 0.1-9 cm 2, preferably 0.25 to 5 cm 2, more preferably 0.5-4 cm 2, such as 1-3 cm 2 and / or or wherein a density of holes is 100-2500 / m2, preferably 250-1000 / m2, more preferably 400-600 / m2, and / or wherein the holes are distributed in a regular pattern, such as trigonal, square, diamond, hexagonal and octagonal. Device as claimed in any of the foregoing claims, wherein a thickness of the lower cover layer is 0.2-0.8 times a thickness of the upper cover layer, preferably 0.3-0.6 times, such as 0.4-0.5 times and / or wherein a thickness of the lower cover layer 1 Is 5-7 cm, such as 2-3 cm. Device as claimed in any of the foregoing claims, wherein a first amount of brood on loading of compost is 0.7-1.5 kg / m2 for the top cover layer, preferably 0.85-1.25 kg / m2 and / or wherein a first amount of brood on loading of compost is 0.45-1.0 kg / m2 for the lower cover layer, preferably 0.65-0.9 kg / m2 and / or wherein the ratio between a first amount of brood when loading compost in the upper cover layer / lower cover layer 1.1- 2, preferably 1.2-1.5, such as 1.25-1.4, and / or wherein a density of the upper cover layer is 600-1100 kg / m3, preferably 700-900 kg / m3, and / or wherein a density of the lower coating is 800-1400 kg / m3, preferably 900-1200 kg / m3. Device as claimed in any of the foregoing claims, comprising 1-7 trays, such as 2-6 trays, wherein each tray comprises a sequence of layers, and / or wherein the bottom component of the upper and lower layer preferably comprises pasteurized material, such as peat . 7. Device as claimed in any of the foregoing claims, further comprising a support mesh, such as a chicken mesh, the mesh preferably comprising openings with an area of 1 to 16 cm 2, more preferably 2-10 cm 2, such as 4-6 cm 2, wherein the mesh is preferably located below the bottom cover layer, more preferably below the bottom support layer and / or wherein the device comprises supporting means, such as bars. A method for harvesting mushrooms, comprising the steps of: providing a device according to any of claims 1-7, growing mushrooms, and harvesting mushrooms. 9. Method according to claim 8, wherein the mushrooms are selected from the group consisting of Agaricus species, such as Agaricus Bisporus, Agaricus brasiiliensis, Agaricus subrufescens, Agaricus Blazei (Murill), Agaricus bi-torquis, Pleurotus species, such as Pleurotus ostreatus , Pleu-rotus sapidus, Pleurotus citrinoplieatus, crimini mushroom, portobello mushroom, Lentinula edodes, Grifola frondosa, Agro-cybe aegerita, Cantharellus cibarius, Hericium erinaceum, and enoki (flammulina velutipes).