Fungiculture

Fungiculture is the cultivation of fungi such as mushrooms.

John Abercrombie

• Spawn is obtained the most readily and in abundance in parcels of decayed dung and dungy composts; but commonly more plenteously and good in rotten horse stable dung, composed of the short dung and moist litter together, as cleared from the stables, either collected in dung-heaps or formed into hot-beds, composts, &c. when it has remained some months till its fermentation and heat are decreased, and a state of decay and putrefaction brought on. This kind of dung being more adapted to the generation of spawn than any other, is a favourable circumstance, as horse dung is to be every where met with.

• In all decayed dung-heaps and hot-beds, old dungy composts, and well dunged foils, not too wet, or the dung very buttery rotten, you may be successful.

• The best season to find spawn in the greatest plenty and perfection is the Autumn and early part of Winter; for spawn being of a singular temperament, impatient of much wet, or cold, or of being much exposed to the open air, it should be carefully collected for use before it is injured and weakened by the inclemency of the weather; for it is of much importance to have it in full vigour, when it may be directly used in spawning beds, provided it be quite dry; otherwise let it lye by for a few weeks.

• Let it be observed... of the spawn in general, that it must be kept dry till wanted; and if any lumps at first gathering appear wet, spread them in a shady covered place before they are laid up in a house; for it is of much importance to have the spawn perfectly dry when planted.

• No dung answers the purpose so well as that of the horse, the dung and urine of this animal, together with the wet straw litter of the stalls in the stables, being of a hot quality, ferments, and acquires a strong degree of heat of long duration; but as this heat generally proves too violent at first for the growth of vegetables, the dung should always be previously reduced to a proper temperature, by casting it up in an heap, and turning it once or twice in order to evaporate the rank burning steam before its fermentation.

• Let it remain together three or four weeks, according to the quantity and strength of heat, in order that it may meliorate, by discharging the rank obnoxious steam; and if it is turned over once every week, it will still incorporate the parts more effectually, and give an additional vent to the fierce ferment.

• In a week or fortnight after the bed is made it will heat violently, and probably continue for a fortnight or three weeks or more, especially if of a considerable extent, and must on no account be spawned till the violent heat subsides and becomes reduced only to a gentle warmth, otherwise the spawn will be totally destroyed and the whole work to be done over again, and this is often the cause of so many Mushroom beds proving barren, the spawn perishing at the first setting off.

• Great humidity is a certain enemy to Mushroom beds, as it soon exterminates the whole spawny substance.

• In the work of spawning the bed, the utmost precaution must be observed, not to perform it until the great heat has passed off, and left only a very gentle warmth; for the small tender spawny-fibres and minute knots of embryo plants would, by one day's great heat, be totally destroyed.

William Robinson

• My reasons for writing this book are: First, that Mushroom Culture is but little practised in this country compared to the extent to which it ought to be, considering the abundance of the necessary materials... every place in which a gardener and horses are kept should be abundantly supplied with Mushrooms throughout the greater part of the year. Secondly... a simpler and fuller account of it than has yet appeared in the English language is desirable for the unpractised amateur and cultivator. Thirdly, Mushroom Culture is at present confined to a too narrow groove... if the knowledge of how easily and in how many ways they may be grown, apart from the usual mode, were sufficiently spread, it would lead to the production of many times our present supply. Fourthly, [I have] a desire to introduce to this and other countries the system of Mushroom Culture on a very large scale carried on in caverns beneath the environs of Paris, which caverns I visited in 1868.

• In every garden where Mushrooms are grown abundance of spawn may be made. ...by saving the spawn as the Parisian growers do, all expense for this article is abolished.

• The introduction of the Mushroom into our domestic economy in as great a degree as we have it in our power to produce it, would practically be the addition of a new agent in our cuisine, second to none for its delicacy, and unsurpassed for utility. ...every cart of stable-manure produced in this great horse-keeping country may, on its way towards decomposition and replenishing the earth, be made a nidus for furnishing many dishes of them.

• We know that the gills are simply surfaces on which germs or spores are produced. The membrane that covers the spore plates of a single mushroom would cover a large space if spread out, and the spores are counted by myriads. We can see them clearly enough under the microscope—can see in what manner they are borne on and fixed to the gills; but of the history of their lives, from the time they fall from the surfaces on which they were born, till the "young mushroom" or inflorescence is vigorously pushing up from the mass of delicate vegetation which they have given rise to in earth or decaying manure, we know nothing. However, the preparation of the spawn, and the subsequent management of it in the mushroom-bed, are the matters which really concern us.

• How is spawn obtained in the first instance? It is found in a natural state in half-decomposed manure-heaps, in places where horse-droppings have accumulated and been kept dry, in riding-schools, sheds to which horses have long had access, in "mill tracks" under cover, in pastures, in partially decayed hotbeds, &c., and rarely or never in very moist or saturated materials. This spawn, sometimes termed "natural" in this country, and called by the French "virgin spawn," is the best that can be obtained, and should be used in preference wherever it can be found. To use it, all that has to be done is to divide the material permeated by the white spawn into pieces a few inches square, and say an inch or more thick. They will of course break up irregularly, but all should be used, whether of the size of a bean, or nearly that of the open hand. Then they are inserted into the surface of the mushroom-beds in the ordinary way.

• In most places where horses are kept, opportunities of finding this spawn occur. Its white, filamentous, and downy threads have the odour of mushrooms, and the spawn is, therefore, very easily recognised. It should be generally known that it need not be used when found, but may be dried, and kept for use in a dry place for years, and has been known to keep as long as fourteen years.

• To preserve spawn found in a natural state, nothing more is required than to take up carefully the parts of the manure in which it is found, not breaking them up more than may be necessary, and placing both large and small pieces loosely in rough shallow hampers. These should be placed in some dry airy loft or shed till thoroughly dry, and afterwards kept in some perfectly dry place, packed in rough boxes till wanted for use.

• To secure good spawn, we have only to do as the French growers do: take a portion of a bed where it is thoroughly permeated by the spawn and before it begins to bear, and preserve it for future use.

• The important thing should be to ascertain if the spawn spreads through the bed properly. The usual practice is to earth up the bed immediately or very soon after it is spawned, and not a few take no further notice of the bed or beds till the time arrives when the mushrooms ought to appear. A better plan is not to finally earth the bed until the spawn is seen beginning to spread its white filaments through the mass; and should it fail to begin to do this in eight or ten days after spawning—the conditions being favourable—it is then better to insert fresh spawn or to re-make the bed, adding fresh materials if it be found to fail from being too cold. If people generally were to see whether the spawn had "taken" freely, instead of waiting for many weeks, not knowing whether it had or not, there would be fewer disappointments in mushroom culture.

• As regards the kind of soil used in earthing, it is not of nearly so much importance as is generally supposed; almost any soil will do; but those having heaps of good maiden loam laid by for gardening purposes will prefer to use a coating of that. ...The beds in the caves around Paris are covered over with a white putty-like substance, which would be sufficient to shake the nerves of any British mushroom grower... It is simply the fine rubbish from the stone breakage moistened, and smoothly and firmly pressed over the beds. ...The final covering of from one to two inches of loam or other soil should not be applied till the spawn has begun to spread through the bed, but a very thin layer of dryish loam may be placed on with advantage just after spawning has taken place, as it will serve to make the surface of a more equable temperature. It is a mistake to suppose that a deep covering is of any advantage. The final earthing should be of soil sufficiently moist or moistened to permit of its being pressed into a firm surface. However, unless it is exceptionally dry, a mere sprinkling of water will suffice.

• As the materials of mushroom-beds are generally moist, and as but little evaporation can take place in the structures in which they are usually grown, water is rarely necessary, and should not be applied until the surface of bed and soil are really dry. It should then be given copiously enough to well moisten the bed, and it should be soft water heated to a temperature of 80 degrees given with a fine rose, and steadily and patiently applied equably over the whole surface of the bed. Waterings that merely wet the surface and saturate the crevices or lower parts of the bed are of no use. If one drenching is not sufficient to moisten the bed properly, another should be given. ...I can scarcely conceive a case in which it will be necessary before six or eight weeks after the formation of a bed, and I have seen fine crops gathered without a single watering having been given. In watering old beds one ounce of guano to the gallon of water will prove beneficial.

• Woodlice are the greatest pests the mushroom-grower has to dispose of, and the most effective way of getting rid of them is by destroying them with boiling water. The surface of the bed being firm and covered with smooth firm soil, the only likely place to afford these creatures the interstices they usually retire into... is round the edges of the bed, and in the slit which often occurs between the bed and wall or sides of the shelves that support it. There they are likely to be found in great numbers and may be destroyed wholesale by pouring boiling water all along the crack. If the beds be covered with hay or litter, it will be necessary to remove this and allow them time to retreat into their hiding places; and if the beds are made in any position that permits of the woodlice hiding in other places than the interstices round them, these places should be sought out marked and receive a searching dose of the scalding water all at the same time. ...the scalding water must not in any case be applied to the surface of the bed. ...Should this plan fail half an ounce of sugar of lead mixed with a handful of oatmeal and laid in their tracks will quickly destroy the pests.

• The small mite is most destructive in a high temperature, and in summer, Mr. Cuthill says, "the maggot" will not breed in a house where the temperature does not exceed sixty degrees, and it is in hot, dry, and half-neglected houses that this pest is usually seen in summer. At that season there is little need to grow mushrooms indoors... The entrance of rats should also be guarded against.

• It may savour of the ridiculous to say that a plant growing upon a dung bed may fail from the want of manure. Yet such is literally and positively the fact. Beds become worn out, the produce small and spindly, and we directly do away with them and make fresh ones. Instead of doing this, give the bed a thorough soaking of stable urine and water, at the temperature of 80 degrees, using the urine in the proportion of one part to five of soft water, and adding a wineglassful of salt to each canful; then coat the bed with fresh soil, cover it down with mats so as to promote the heating, and a second crop as good as the first may be obtained.

• Where there are several beds in bearing, the mushrooms should be gathered every morning. In all cases they should be pulled or twisted out, never cut out, so as to leave decaying stumps in the beds. The holes made by pulling out the mushrooms should be filled with a little fine loam, of which a small heap may be kept in the house for this purpose.

• French cave cultivators find it necessary to shift from cave to cave, and find that after a cave has been in use a certain time, mushrooms cease to be produced in it should act as a caution in this respect. In summer, when there is no need to attempt the culture indoors, the house should be thoroughly cleaned out, lime-whited, every surface scraped and washed, and the house freely opened, so as to thoroughly sweeten it.

Benjamin Minge Duggar

• From the time of Pliny, and perhaps much earlier, this plant has been sought as an article of diet, and it has been cultivated for many centuries.

• It is, in fact, for the production of this powdery mass that the mushroom, as we know it, is formed. The brown powder consists of innumerable minute simple cells in the form of ovate bodies, termed "spores." These serve for the reproduction of the mushroom. They are equivalent to the green powder mass produced by molds which grow upon cheese, bread, and the like. Their function is that of reproducing the mushroom, but they should not be termed seeds.

• This lowly organized mushroom plant differs very much from our common cultivated green plants. There are no such organs as root, stem, and leaf, and a well differentiated body is only formed when the mycelial threads have stored up nourishment and are ready to develop the mushroom, or sporophore, which is to bear the reproductive bodies, or spores.

• Up to the period covered by the present investigations the spores have seldom been used in a commercial way. The spawn maker has depended upon finding spawn in his pastures, or in his manure piles, or having it appear spontaneously, as it is termed, in prepared beds; and this spawn he has used in the propagation of other spawn by a process which we may liken, perhaps, to that of propagation by cuttings.

• Mushrooms may be grown in any place where the conditions of temperature and moisture are favorable. A shed, cellar, cave, or vacant space in a greenhouse may be utilized to advantage for this purpose. The most essential factor perhaps is that of temperature. The proper temperature ranges from 53° to 60° F., with the best from 55° to 58° F. It is unsafe to attempt to grow mushrooms on a commercial basis... at a temperature much less than 50° or greater than 63° F.

• In the growing of mushrooms for commercial purposes the beds should be constructed of stable manure which has been fermented or composted.

• If well pressed down and merely moist, the manure will not burn and, moreover, there will be no tendency for a sour fermentation to become established. In from fifteen to twenty-one days, depending upon the conditions, the temperature will begin to fall, the violence of decomposition will begin to show a subsidence, and the compost will be ready for the construction of the beds. The bacteria of rapid decay will become less and less abundant, and finally, when the beds are prepared as subsequently described, the spawn will be able to grow in spite of the bacteria present.

• It is the custom with some growers to mix a small quantity of loam, about one-fourth, with the manure. ..When sawdust or shavings are employed for bedding the animals, the composting may require a somewhat longer period.

• The manure is always ready for the construction of beds when... nearly all objectionable odors are lost and a sweet fermentation, as growers term it, has begun.

• When shelves are used one should be careful to whitewash these after each crop in order to avoid the increased danger from insect depredations.

• Under favorable circumstances a bed may come into bearing within six weeks. ...eight weeks may more nearly represent the average conditions. ...if at times a very low temperature has prevailed, bearing may be still further delayed. ...the period of production or the profitable "life" of a successful bed may vary greatly ranging from five weeks to as many months.

• Many growers think that there is profit in a bed which yields one-half pound per square foot of surface area.

• The manure is either used alone or with the mixture of some rich loamy soil, about one part of soil to four or five parts of manure. Most commercial growers of mushrooms do not employ any soil, but use the manure pure. This gives much less trouble and is usually considered a more successful method than the mixture of soil. When the beds are made up without soil, a layer of manure is spread over the bottom; usually the coarser and more strawy material is selected for the bottom layer since this ferments for a longer time and keeps up the heat in the bed. When the first layer of manure is thoroughly tramped or pounded down, another layer is added which in like manner is thoroughly tramped down. This is continued until the bed is filled, when the manure should be from 10-12 or 14 inches deep and must be firmly packed. In using soil to mix with the manure a layer of the manure is first put in the bottom of the bed as described. Over this is sprinkled a thin layer of soil. Another layer of manure is then added and another sprinkling of soil. Each time the layers are thoroughly packed down, as before, until the beds are filled.

George Francis Atkinson, Robert Shore

• Cellars or basement rooms where the temperature in the winter does not go below 55° or does not rise above 65°, are suitable places for growing mushrooms. It is not advisable to make them under the living part of the house, since the odor of the manure will fill the house.

• The best material which has been found for the cultivation of mushrooms is horse manure as it comes from well-littered stables. ...While it is desirable to have some straw in the manure a large percentage of straw is objectionable, and when a large amount of straw is present the coarser straw should be removed.

• The manure is cured by allowing it to heat and ferment in the pile, but great care must be exercised not to allow it to burn, that is, it must not get white inside. To prevent its becoming too hot, the manure must be forked over and made into a new pile. ...It may feel to the hand quite hot, but as long as it does not turn white or get too dry the heating will not harm it. It is far better to handle the manure in such a way as to avoid the necessity of moistening with water; but if it is too dry to begin with or if it becomes too dry in the process of heating, enough water should be sprinkled on to make it moist, but not wet. It usually requires from 10-15 or 18 days to cure manure, and it is then ready for making into beds. It should not be made into beds, however, until the temperature of the fermenting manure is down to about 100° Fahr.

• Where soil is used, care should be exercised in its selection. It should be a good, loamy, rich soil. The best to use is rotted sod, since in the decaying roots and stems there is considerable fresh organic material which is excellent food for the mushrooms.

• A thermometer should be kept in some part of the bed and if the bed is large the temperature should be tested at different places every day or so. The temperature should be taken several inches below the surface. The proper time to spawn is when the temperature is from 70° to 75° F.

• Suitable pieces of spawn for planting are those about two inches in diameter. ...These are planted according to the wishes of the operator from eight to ten or twelve inches apart in the bed. The first row is planted four to five or six inches from the edge of the bed, In the second row the pieces may alternate with those in the first. A hole is well made by a dibble or sharpened stick, which is thrust into the bed and moved around in order to make a hole which will admit the pieces of spawn. The hole should be small enough so that when the spawn is pressed into it, it will fit very tightly. The spawn should be planted from one to two inches below the surface of the bed and then covered with the manure removed in making the hole. This should then be packed down hard. The beds are then left in this condition for about a week, and in the meantime may be covered loosely with excelsior or straw to prevent too rapid evaporation of moisture and also to prevent too rapid lowering of the temperature.

• Casing the beds... consists in covering the beds with an inch to an inch and one-half of good soil, the same kind of soil as is used for mixing in with the manure. The object in casing the beds with soil is to retain the temperature within the material, which is necessary for the maintenance of the growth and it also provides a firmer and cleaner substratum in which the stems of the mushrooms are mostly formed and they are thus cleaner when picked. In from six to seven weeks mushrooms should begin to appear.

• The spores are very light and are easily wafted about by the gentlest breeze, so that in the fields the winds scatter the spores far and wide, and thus give an opportunity for the mushrooms to grow in fields where food and other favorable conditions are present. These spores germinate by producing a very delicate white thread which branches to form a mat of fiber like substance. Many of these little threads unite into a cord or string which is also white... This fiber like substance is known as the mycelium, though mushroom growers often speak of it as the "fiber." It can readily be seen in all good spawn.

• In practical mushroom culture, the spores of the plant, though they serve as seeds, are not used for planting since the use of the mycelium or fiber is a far better means of propagating the mushroom.

• In the soil and in the manure of the bed, it forms a large mat of these fibers or mycelium cords. Finally when a sufficient mass of the mycelium has formed the mushrooms begin to develop. The mushrooms are formed by the growth of a large number of the same delicate threads, but a larger number of them grow together and they grow upright.

• Sometimes the spawn will grow very profusely above the piece of brick which has been planted and appears on the surface of the soil. When this is the case, large numbers of minute buttons make their appearance and form very beautiful objects. All of these, however, do not make mature mushrooms since there is not food enough for all. Those which get the start grow to maturity, while the smaller ones die.

• As the button stage is reached, the upper part expands into the cap. The stem is shown as a short cylinder. The gills are formed within the upper part of the button and are first covered by the outside mass which stretches as the cap expands to form the veil. Finally this veil breaks exposing the gills on the underside and hangs down on the upper part of the stem as the collar or annulus.

• The mushrooms are ready to pick about the time the veil breaks. ...In picking the mushrooms the best way is to take hold of the plant by the cap. By moving the hand from side to side with a slight circular motion the stem is freed from the soil. ...After picking the mushrooms, wherever the stems have made a little hole in removing them from the earth, a little soil should be added to cover this up again.

• The beds need sprinkling occasionally with tepid water, but should never be made very wet. Insects can largely be avoided by care in securing good manure and in having the premises well cleaned before the beds are made. When mushrooms are grown in successive years in the same place, the place should be given a very thorough cleaning during the summer. All manure and soil is removed, the beds are cleaned out well, and the walls and boards often whitewashed. It perhaps would be well also at this time thoroughly to disinfect the premises with a solution of formalin.

Thomas H. White

• From the records in ancient history we learn that mushrooms have been esteemed as an important food delicacy from very early times.

• There are numerous species and some of them are poisonous. The species that is cultivated, almost invariably, is the one that grows in the pasture fields. ...The botanical name of this species is Agaricus Campestris.

• The part that is eaten is the fruit or spore-bearing part of an underground fungus. This fungus seems to live upon and among the roots of the grass. The fact that the mushroom is found in greater abundance where cattle are pastured would seem to indicate that the excreta of animals has something to do with their development.

• The action of the fungus as it spreads through the turf has the effect of making the grass turn dark green in color. The habit of growth of the fungus is of such character that the patches spread out in somewhat of a fan shape, which develops into a part of or sometimes a whole circle.

• It seems to be necessary for the soil of the field to become quite dry before the mushrooms develop. Where pastures have become inoculated the mushrooms always appear when there has been sufficient rain, after a long dry spell, to thoroughly moisten the earth. If the rain is continued and the soil becomes well soaked, the mushroom production is checked and no more will be found until the soil has again been through another dry period.

• Many persons are afraid to gather mushrooms for fear that they may get some of the poisonous species. There is not much danger of this if they are gathered in the open pasture. The poisonous species are more generally found in places where there are dead or decaying trees.

• The edible mushroom (Agaricus Campestris) is, after some little observation, easily distinguished from other species. In the pasture fields they vary in diameter from the size of a button to that of a saucer. In the young stage, which is the proper time to gather them, they are white on top and delicate pale pink beneath. As they get older the underneath side, or "gills," turn black.

• The cultivation of the mushroom in an artificial way was attempted centuries ago. It was not until about the seventeenth century, however, that any great headway was made. The French at that time conceived the idea of getting pieces of the fungus and starting it in manure. It is quite probable that they got this idea from observation of the fine mushrooms that will grow in this material when it becomes packed down in a moderately dry shed.

• There is a kind of mushroom spawn grown in England at the present time that is called "Milltrack." It is said to have originated in the tracks of the horses that pulled the horse-power grinding mills.

• Probably the first largest artificial mushroom beds were those made by the gardeners of Paris in the caves beneath that city. Piles of horse manure were used to receive the broken up pieces of the fungus, or spawn as it came to be called. When making new beds the Paris gardeners usually broke up an old bed that had passed the limit of profitable production and used chunks or flakes of it to spawn the new beds.

• The English later on conceived the idea of making brick-shaped pieces of a mixture of horse and cow manure, and under suitable conditions for growth inoculated each brick with other spawn from the milltrack or pasture. This was afterwards allowed to dry and would, when kept dry and cool, remain alive for several months.

• Until about the beginning of the present century all the spawn used in America was imported from England or France. Interest was started in its manufacture here by the work of B.M. Duggar and Miss Ferguson, of the United States Bureau of Plant Industry. They gathered the spores from different mushrooms and produced the mycelium in test tubes filled with horse manure. This was afterwards transferred to the manure bricks and was put on the market as "Pure Culture Spawn." By this method the varieties were isolated and could be kept pure. Since that time mushroom culture has had a great boom.

• The manufacturers of spawn started a very active propaganda by advertising in the magazines. They asserted that mushrooms could be grown in any outhouse or cellar, at the same time giving the impression that any one could be successful and that there were almost unlimited profits in the business. Many have been greatly disappointed, while others, who have had the right conditions for their growth, have been encouraged and made large profits.

• Until now there has been no material discovered that will produce mushrooms as satisfactorily as horse manure. As large quantities are needed and as it is in good condition to produce other crops after the mushrooms have been harvested, the grower should have sufficient land to take care of this.

• Under very special conditions a good crop may be secured without any particular alterations, but as a rule profitable crops will only be secured when the house is built so as to supply the proper amount of heat and moisture.

• It may be possible to select varieties to suit varying conditions.

• Mixing... loam with the horse manure not only prolonged the time the beds produced but also made quite a substantial increase in the yield. It would also seem that the cow manure was so cool in the beginning as to retard the crop as... the cow manure with the soil produced very lightly at the start.

• Covering the beds with straw held the moisture more uniformly, which resulted in a greatly increased production.

• Under dry conditions a rich loam soil when used for "casing" the beds gave better results than a poor sandy or clay soil. Also under rather better moisture conditions the richer materials proved the best.

• The manure from the horse barn produced nearly double the quantity of mushrooms as that from the cow barn.

• Loam mixed with the manure caused an increase in the yield and prolonged the production. Loam also had the effect of decreasing the heat from fermentation when the beds were first made up.

• Many daily readings of the thermometer show that after fermentation of the manure stops, the temperature of the bed will fluctuate with that of the house. This shows the great necessity of having the mushroom house properly warmed and insulated.

• Until the present... nothing has been discovered that is as suitable and available as animal manures. Of these, that of the horse is the best. This, to be entirely suitable, should come from stables where the animals are fed on hard grains and hay. The bedding should be straw and well soaked with urine. Any long unsoiled straw should be taken out. Some of the older growers used to discard practically all of the straw and use nothing but the droppings. Manure from stables where the owners are careless about keeping them clean will often produce a better crop than that from stables where the soiled straw is removed each day and replaced with fresh. Avoid manure from stables where old hay is used for bedding...

• When manure is placed together in large piles it immediately commences to ferment. This fermentation is needed to put the manure into a proper condition for the mushroom spawn. But, it must be regulated and controlled, or the violent heat would destroy the elements needed for the mushroom's growth. ...If the manure is dry it should be moistened. Just enough water should be used so that when the manure is ready to go into the mushroom house no water can be squeezed out, if a portion is wrung or twisted tightly in the hands. After the manure has been moistened and piled it should be covered with three inches of good soil. ...If it is hot and there are any particles in the center that show evidence of "fire-fanging" it should be turned immediately. Fire fanging is characterized by the strawy particles having a white mouldy appearance. ...At the same time the soil that was spread over the pile should be spread and mixed all through the manure. After a day or two the pile should again be turned. This turning process should be repeated until all the particles have become of a rich coffee-brown color. This will be a week or ten days after the manure is collected, depending upon the season of the year.
  When the condition of the manure has arrived at this stage no time should be lost in getting it into the beds. Care should be taken in placing the prepared manure on the shelves or beds, that it is spread smoothly and evenly and well packed down. Not less than eight inches and not more than twelve inches will be found the right depth, under ordinary circumstances, for the manure on the shelves or beds.

Benjamin Minge Duggar

• The groups of fungi discussed include primarily those which are edible and readily distinguished. They are all economic plants of our woods and fields worthy of being known by every one.

• In a commercial sense... the cultivated mushroom Agaricus campestris, and the allies of this form are everywhere in America the dominant species of interest, and usually the only species of interest; so that among certain classes of persons it is not strange to find a tendency toward such restrictions of the word as to include merely these commoner cultivated forms.

• The use of "mushroom" as the opposite of "toadstool" with respect to edibility is unfortunate,—"mushroom" in this sense denoting any edible species, and "toadstool" all the poisonous ones, or sometimes, indeed, any of the fungi which are not eaten.

• If one should take a full-grown mushroom after the under surface of the cap has become exposed by the breaking away of the annulus, twist the stem until it breaks away from its attachment to the cap, or cut it off short, and then place the cap gill surface downward on a sheet of white paper, there will be found in the course of twenty-four hours, more or less, a print. ...The print obtained is a fairly good reproduction of the projected form of the gills, being composed of a mass of brownish-black powder which has fallen from the gills themselves. It is... for the production of this powdery mass that the mushroom, as we know it, is formed. The brown powder consists of innumerable minute simple cells in the form of ovate bodies, termed "spores." ...They are equivalent to the green powdery substance produced by moulds which grow upon bread, cheese, and the like. Their function is that of reproducing the mushroom, but they should not be termed seeds. ...The entire gill surface is the "hymenium," or spore-bearing layer.

• Although the spores are normally the propagative bodies and undoubtedly serve in the open for the distribution of the species, growers cannot employ these directly in the production of mushrooms. In fact it is difficult to germinate them in the laboratory...Under certain favorable conditions each of these minute cells is, however, capable of germinating and producing first a germ tube, ultimately a filamentous or threadlike growth, known as the mycelium. This mycelium arises from the first small germ tube by subsequent branching and continued ramifications, and under favorable conditions it grows until the rapidly elongating filaments penetrate the substratum in every direction. The growth of the mycelium in any suitable substratum yields a characteristic "spawn," and "spawn" refers merely to this phase of the mushroom growth in visible or extensive quantity. It is appropriately called the vegetative phase. Spawn may also be produced from fragments of the living tissue, if pure culture methods are employed...

• Mycelia of other fleshy or woody fungi invade a great variety of substrata. Rich earth, moist leaves of the forest floor, fallen timber, and even the trunks of living trees are all invaded by numerous species, each species having certain general habitat requirements.

• When..."spawn" is found in any particular location it may not be easy to name the species from this spawn alone; that is, the "mushroom," or sporophore, is required. True, one may become expert in recognizing kinds of spawn, but the important thing at first is to recognize the mushrooms.

• It would scarcely be practicable to attempt to describe in detail the appearance of "spawn" since that is best gained by experience with it, for once mushrooms are grown and the fresh spawn in the bed examined carefully, there will be no further difficulty in recognizing Agaricus spawn.

• The earlier history of the field agaric in cultivation remains... to be worked up from the scattering references. ...this species was cultivated in France during the reign of Louis XIV, and it is certain also that it was considered a luxury a century or two earlier. Tournefort has left an interesting note, under date of 1707, of the cultural operations of his period. While little was then known of the life relations of the organism, it appears that the requisite conditions for successful culture were clearly appreciated. No mention is made of the cultivation in caves at this time. In fact, it does not appear that the underground quarries in and near Paris, which are now the famous mushroom gardens of the world, were commonly used for growing prior to the beginning of the 19th century. Among the references which can be had from early Greek or Roman authors, however, no evidence has been brought to my attention indicating that any special consideration was accorded this species in those times.

• In France the mushroom industry has fallen heir to the subterranean quarries which now constitute a very extensive array of artificial caves especially under Paris or in its environs. ...In the caves of the suburbs mushrooms are so commonly grown that "champignonière" (mushroom cave) is practically synonymous with "carrière" (cave). The cave systems are very well ventilated by means of chimneys or chutes. The change of air is often facilitated by small charcoal fires beneath these air chutes and occasionally by the use of special ventilating devices.

• Caves or deep cellars have always the advantage of permitting mushroom production during a long period; indeed, frequently throughout the year, but they must offer the possibility of adequate ventilation.

• It is often convenient to construct the house over an excavation which may be at least several feet lower than the natural surface. In building houses of this type, however, arrangement should be made for the utmost convenience in unloading the compost and for cleaning out the old beds. The greatest economy is attained by the construction of houses high enough to accommodate the beds in tiers of from two to five.

• In selecting manure for mushroom work only that which is recognized as of the highest quality should be taken. It is the general experience that considerable bedding straw should be present with the manure, and if good straw it is not likely to contain too much, but even a small quantity of "weeds" is a nuisance. The straw of the various grains seems to possess distinct advantages over that of other grasses, perhaps on account of a certain resistance to complete fermentation, or decay, yielding a highly porous substratum which maintains an excellent physical condition in the beds.

• Manure from animals fed largely upon grass has not proved satisfactory in such tests as have been made, and French experience rules out that obtained from stables employing chiefly leguminous fodders. The French ideal is manure from grain fed animals bedded with rye straw.

• The manure contains many soluble organic substances which invite a vigorous development of mould fungi, if it is not fermented. During the fermentation process the common mould fungi do not, as a rule, develop profusely, but bacterial and direct chemical action is facilitated. The end result is such a stage in the decomposition of the material as will favor the growth of mushroom spawn rather than the mycelia of moulds.

• If fresh stable manure is secured it should be thrown into piles not more than 4 feet high and of any extent desired. ...At first the manure should be thoroughly wet throughout. Subsequently it will be necessary to maintain it in a moist state, and to turn, or fork over, the pile three or four times, or oftener, depending upon the conditions. Under ordinary circumstances if the manure is well moistened it may be properly fermented in three weeks or somewhat less, being turned at intervals of from three to five days. The presence of shavings or sawdust may necessitate a longer fermentation interval...

• At each turning it should be seen that there is sufficient moisture throughout the pile, and it is usually necessary to water during the turning process, in order that the moisture may reach all parts. With the maintenance of adequate moisture the attainment of a temperature of 140° to 150° F between the first three turnings may be considered advantageous. If there is little moisture, the manure will "burn" easily and it will require a much longer period of fermentation.

• Whether it "burns" or not, the best type of fermentation, as my experiments have repeatedly shown, is obtained only when the temperature remains for several days at a time above 125° F.

• "Burning" is indicative of a fairly high temperature combined with a rapid drying out. In a properly arranged compost pile the greatest "burning" will occur just beneath the surface, but it is still a question as to what extent "burning" injures the compost. Certainly a reasonably good yield may be obtained from such material.

• During composting the manure should lose practically all objectionable odor, and with material properly prepared there is no unpleasant feature after the preparation of the beds. Other unmistakable signs of sufficient composting are the oleaginous "feel," the pliability, and the uniform brown color of the straw. Commonly the temperature declines to about 120° or 130° F. As soon as the compost is ready it is desirable to make the beds and to have the spawning follow as promptly as possible....

• It is... preferable to have the compost made under cover when this is feasible, particularly if prepared during mid-summer or during freezing weather. It should also be stated that manure which has been piled in a barn lot or otherwise subjected to leaching will have lost much of its value. In short, never use for compost anything but the best fresh stable manure and thus you will eliminate many difficulties.

• John Abercrombie, The Garden Mushroom: Its Nature and Cultivation (1779)
• George Francis Atkinson, Robert Shore, Mushroom Growing for Amateurs (1905)
• Benjamin Minge Duggar, The Cultivation of Mushrooms (1904)
• Benjamin Minge Duggar, Mushroom Growing (1920)
• William Robinson, Mushroom culture: Its Extension and Improvement (1870)