Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. Part 28

It is the practice in some cases where the bed lies against the side of the house to build up the material of the bed at the rear, that is, at the side of the house, much deeper than at the front, so that the depth of the bed at the back may be eighteen to twenty inches or two feet, while the front is eight to ten or twelve inches. This provides a slightly increased surface because of the obliquity of the upper surface of the bed, but it consumes probably a greater amount of material. It probably is not advantageous where the operations are carried on on a large scale, where abundant room is available, where the material for making the beds is expensive, and it is desirable to obtain from the material all that can be drawn in a single crop. The same practice is sometimes recommended and followed in the case of the beds made in cellars.

In the making of beds with fresh material, that is, with unfermented manure, as was done by Mr. William Swayne of Kennett Square, Pa., one season, the coa.r.s.er material is put in the bottom of the bed, and then as the manure is distributed in the bed the soil is sprinkled on also, so that finally when the bed is completed the proportions of soil and manure are the same as when it is mixed in at the time of fermentation.

In making the beds in this way, should any one be led to attempt it, it would be necessary to guard against a too high temperature in the fermentation of this fresh material; the temperature should not run above 130 degrees. It would also require a longer time from the making of the bed to planting the sp.a.w.n than in the case of those beds where the manure is fermented and cured before being made up. Probably the total amount of time from the beginning to the completion of the preparation of the bed for sp.a.w.ning would not be greater, if it would be so great.

The beds all having been made, they are left until they are in a suitable condition for sp.a.w.ning. The determination of this point, that is, the point when the beds are ready for planting the sp.a.w.n, seems to be one of the most important and critical features of the business. The material must be of a suitable temperature, preferably not above 90 F., and not below 70. The most favorable temperature, according to some, other conditions being congenial, ranges from 80 to 85 F., while many prefer to sp.a.w.n at 70 to 75. Many of the very successful growers, however, do not lay so much stress upon the temperature of the bed for the time of sp.a.w.ning as they do upon the ripeness, or the cured condition, of the material in the bed. This is a matter which it is very difficult to describe to one not familiar with the subject, and it is one which it is very difficult to properly appreciate unless one has learned it by experience. Some judge more by the odor, or the "smell,"

as they say, of the manure. It must have lost the fresh manure "smell,"

or the "sour smell," and possess, as they say, a "sweet smell."

Sometimes the odor is something like that of manure when sp.a.w.n has partly run through it. It sometimes has a sweetish smell, or a smell suggestive of mushrooms even when no sp.a.w.n has run through it.

Another important condition of the material is its state of dryness or moisture. It must not be too dry or the sp.a.w.n will not run. In such cases there is not a sufficient amount of moisture to provide the water necessary for the growth of the mycelium. On the other hand, it must not be too wet, especially at the time of sp.a.w.ning and for a few weeks after. Some test the material for moisture in this way. Take a handful of the material and squeeze it. If on releasing the hold it falls to pieces, it is too dry. By squeezing a handful near the ear, if there is an indication of running water, even though no water may be expressed from the material, it is too wet. If on pressure of the material there is not that sense of the movement of water in it on holding it to the ear, and if on releasing the pressure of the hand the material remains in the form into which it has been squeezed, or expands slightly, it is considered to be in a proper condition so far as moisture is concerned for planting the sp.a.w.n.

WHAT Sp.a.w.n IS.

The sp.a.w.n of the mushroom is the popular word used in speaking of the mycelium of the mushroom. The term is commonly used in a commercial sense of material in which the mycelium is growing. This material is horse manure, or a mixture of one or two kinds of manure with some soil, and with the threads of the mycelium growing in it. The mycelium, as is well known, is the growing or vegetative part of the mushroom.

Sometimes the word "fiber" is used by the mushroom growers in referring to the mycelium which appears in the sp.a.w.n, or in the mushroom bed. The mycelium is that portion of the plant which, in the case of the wild varieties, grows in the soil, or in the leaf mold, in the tree trunk or other material from which the mushroom derives its food. The threads of mycelium, as we know, first originated from the spore of the mushroom.

The spore germinates and produces delicate threads, which branch and increase by growth in extent, and form the mycelium. So the term sp.a.w.n is rarely applied to the pure mycelium, but is applied to the substratum or material in which sp.a.w.n is growing; that is, the substratum and mycelium together const.i.tute the sp.a.w.n.

=Natural sp.a.w.n or virgin sp.a.w.n.=--This is termed natural sp.a.w.n because it occurs under natural conditions of environment. The original natural sp.a.w.n was to be found in the fields. In the early history of mushroom culture the sp.a.w.n from the pastures and meadows where mushrooms grew was one of the sources of the sp.a.w.n used in planting. The earth containing the sp.a.w.n underneath clumps of mushrooms was collected and used.

It occurs more abundantly, however, in piles of horse manure which have stood for some time in barn yards, or very often in stalls where the manure is allowed to acc.u.mulate, has been thoroughly tramped down and then has been left in this condition for some time. It occurs also in composts, hothouse beds, or wherever acc.u.mulations of horse manure are likely to occur, if other conditions are congenial. The origin of the natural sp.a.w.n under these conditions of environment is probably accounted for in many cases by the presence of the spores which have been in the food eaten by the horse, have pa.s.sed through the alimentary ca.n.a.l and are thus distributed through the dung.

The spores present in the food of the horse may be due to various conditions. Horses which go out to pasture are likely to take in with the food obtained in grazing the spores scattered around on the gra.s.s, and in the upper part of the sod, coming from mushrooms which grew in the field. In other cases, the spores may be present in the hay, having been carried by the wind from adjacent fields, if not from those which have grown in the meadow. In like manner they may be present in the oats which have been fed to the horse. In the case of stable-fed animals, the inoculation of the manure in this way may not always be certain or very free. But in the case of pasture-fed horses which are stalled at night probably the inoculation is very certain and very abundant, so that a large number of spores would be present in the manure from horses fed in this way.

The natural sp.a.w.n also may originate from spores which are carried by the wind from the pasture or meadow mushrooms upon manure piles, or especially from spores which may lodge in the dust of the highways or street. Many of these spores would cling to the hoofs of the horses and at night, or at times of feeding, would be left with the manure in the stall. At other times horse droppings may be gathered from roads or streets where spores may be present in the dust. The piles of the droppings acc.u.mulated in this way, if left a sufficient time, may provide natural sp.a.w.n by this accidental inoculation from the spores.

Probably few attempts have been made to grow the natural sp.a.w.n with certainty in this country, though it does not appear to be an impracticable thing to do, since formerly this was one source of the virgin sp.a.w.n in Europe. It is usually obtained by search through stables and barn yards or other places where piles of horse manure have acc.u.mulated and have remained for several months. In some cases the growers keep men employed through the summer season searching the yards and stables over a considerable area for the purpose of finding and gathering this natural sp.a.w.n. It is probably termed virgin sp.a.w.n because of its origin under these natural conditions, and never having been propagated artificially.

The natural sp.a.w.n, as indicated above, is employed for a variety of purposes. It is used for inoculating the bricks in the manufacture of brick sp.a.w.n. It is used for propagating once or twice in the mushroom beds, for the purpose of multiplying it, either in the manufacture of brick sp.a.w.n, or for flake sp.a.w.n, which is planted directly in the beds to be used for the crop. In some places in America it is collected on a large scale and relied on as the chief source of sp.a.w.n for planting beds. In such cases the natural or virgin sp.a.w.n is used directly and is of the first and most vigorous generation. It is believed by growers who employ it in this way that the results in the quality and quant.i.ty of the crop exceed those produced from the market sp.a.w.n. But even these growers would not always depend on the natural sp.a.w.n, for the reason, that collecting it under these conditions, the quant.i.ty is certain to vary from year to year. This is due probably to varying conditions of the season and also to the varying conditions which bring about the chance inoculation, or the acc.u.mulation of the material in the yard for a sufficient amount of time to provide the mycelium.

It would be interesting, and it might also prove to be profitable to growers, if some attempt were made to grow natural sp.a.w.n under conditions which would perhaps more certainly produce a supply. This might be attempted in several different ways. Stall-fed horses might be fed a ripe mushroom every day or two. Or from the cap of ripe mushrooms the spores might be caught, then mixed with oats and fed to the horse.

Again, the manure piles might be inoculated by spores caught from a number of mushrooms. Manure might also be collected during the summer months from the highways and aside from the probable natural inoculation which this material would probably have from the spores blown from the meadow and pasture mushrooms, additional inoculation might be made. The manure obtained in this way could be piled under sheds, packed down thoroughly, and not allowed to heat above 100 F. These piles could then be left for several months, care being used that the material should have the proper moisture content, not too dry nor too wet. This is given only as a suggestion and it is hoped that some practical grower will test it upon a small scale. In all cases the temperature should be kept low during the fermentation of these piles, else the sp.a.w.n will be killed.

One of the methods of obtaining natural sp.a.w.n recommended by Cuthill ("Treatise on the Cultivation of the Mushroom") is to collect horse droppings all along the highways during the summer, mixing it with some road sand and piling it in a dry shed. Here it is packed down firmly to prevent the heat rising too high. A "trial" stick is kept in the pile.

When this is pulled out, if it is so hot as to "burn the hand," the heat is too great and would kill the sp.a.w.n. In several months an abundance of the sp.a.w.n is generated here.

=Mill-track sp.a.w.n.=--"Mill-track" sp.a.w.n originated from the sp.a.w.n found in covered roadways at mills or along tram-car tracks where horses were used. The acc.u.mulation of manure trodden down in these places and sometimes mixed with sawdust or earth, provided a congenial place for the growth of the mycelium. The sp.a.w.n was likely introduced here through spores taken in with the food of the horse, or brought there from highways, if they were not already in the soil from mushrooms grown there. It would be then multiplied by the growth of the sp.a.w.n, and from spores of mushrooms which might appear and ripen. The well tramped material in which the mycelium grew here, when broken up, formed convenient blocks of sp.a.w.n for storage and transportation, and probably led to the manufacture of brick sp.a.w.n.

=Manufactured sp.a.w.n.=--The manufactured sp.a.w.n, on the other hand, is that which is propagated artificially by the special preparation of the substratum or material in which the mycelium is to grow. This material is inoculated either with a piece of natural sp.a.w.n, or with pieces of previously manufactured sp.a.w.n. It is put upon the market in two different forms; the brick sp.a.w.n, and the flake sp.a.w.n. The latter is sometimes known as the French sp.a.w.n, while the former, being largely manufactured in England, is sometimes spoken of as the English sp.a.w.n.

[Ill.u.s.tration: FIGURE 233.--Brick sp.a.w.n. Three "bricks," one marked to show into how many pieces one brick may be broken.]

=Brick sp.a.w.n.=--The brick sp.a.w.n is so called because the material in which the mycelium is present is in the form of bricks. These bricks are about 5 by 8 inches by 1-1/2 inches in thickness, and weigh about 1-1/4 pounds each when dried. The proportions of different kinds of material used in the manufacture of brick sp.a.w.n probably vary with different manufacturers, since there is a difference in the size and texture of bricks from different sources. One method of making the brick sp.a.w.n is as follows: Equal parts of horse dung, and cow dung, and loam soil are thoroughly mixed together to a consistency of mortar. This is pressed into the form of bricks and stood on edge to dry. When partly dry, a piece of sp.a.w.n about an inch in diameter is pressed into one side of each brick. The bricks are then stood up again until thoroughly dried.

They are then piled upon a layer of fresh horse manure about 8 inches deep, the pile of bricks being about 3 feet high. This pile is then covered over loosely with fresh horse manure, a sufficient amount to produce, when heating, a temperature of about 100 F. They are left in this condition until the mycelium or "fiber" has thoroughly permeated the bricks. The sp.a.w.n is now completed, and the bricks are allowed to dry. In this condition they are put upon the market. The bricks made with a very high percentage of soil often have the appearance of dried soil, with a slight admixture of vegetable matter.

Brick sp.a.w.n from other sources presents a very different texture and contains probably a much larger percentage of horse manure, or, at least, a much smaller percentage of soil. The appearance of the brick is not that of soil with a slight admixture of vegetable materials, but has much the appearance of a dried and compressed mixture of horse dung and cow dung, with an abundance of the "fiber" or mycelium, "the greyish moldy, or thready matter," which const.i.tutes the vital part of the sp.a.w.n. In the selection of sp.a.w.n this is an important item, that is, the presence of an abundance of "fiber" or mycelium. It can be seen on the surface, usually showing an abundance of these whitish threads or sheets, or a distinct moldy appearance is presented. On breaking the brick the great abundance of the "fiber" or whitish mycelium is seen all through it. This indicates that the brick possesses a high percentage of the "fiber," an important part of the sp.a.w.n.

One not accustomed to the quality of sp.a.w.n can therefore judge to a certain extent by the appearance of the bricks as to the quality, at least they can judge as to the presence of an abundance or a scanty quant.i.ty of the "fiber." Since the sp.a.w.n remains in good condition for several years, there is usually no danger in the use of sp.a.w.n which may be one or two years old. But it does deteriorate to some extent with age, and young sp.a.w.n is therefore to be preferred to old sp.a.w.n, provided the other desirable qualities are equal. Those who attempt to cultivate mushrooms, and depend on commercial or manufactured sp.a.w.n, should see to it that the sp.a.w.n purchased possesses these desirable qualities of texture, and the presence of an abundance of the mycelium. That which appears devoid of an abundance of mycelium should be rejected, and good sp.a.w.n should be called for. There is no more reason why a grower should accept a worthless sp.a.w.n from his seedsman than that he should accept "addled" eggs from his grocer. In this business, that is, the manufacture and sale of sp.a.w.n, poor material is apt to be thrown on the market just as in the case of seeds, poor material may find its way upon the market. Sometimes this occurs through unscrupulous dealers, at other times through their ignorance, or through their failure to know the quality of the product they are handling.

There are some brands of sp.a.w.n, that is, those manufactured by certain houses, which rank very high among those who know the qualities and the value of good sp.a.w.n. Some large growers send direct to the manufacturer for their sp.a.w.n, and where it is to be obtained in large quant.i.ties this is a desirable thing to do, since the cost is much less. Where obtained from seedsmen in large quant.i.ties, the prices are much lower than where small quant.i.ties are purchased. One of these brands of sp.a.w.n, the Barter sp.a.w.n, is for sale by several different dealers, by Mr. H. E. Hicks, Kennett Square, Pa., by Henry F. Mich.e.l.l, 1018 Market street, Philadelphia, and by Henry Dreer, 724 Chestnut street, Philadelphia.

Another brick sp.a.w.n, known as "Watson Prolific," is for sale by George C. Watson, Juniper and Walnut streets, Philadelphia. James Vicks Sons, Rochester, N. Y., and Peter Henderson & Co., New York City, have their sp.a.w.n manufactured expressly for their trade.

The Barter sp.a.w.n is said to be made fresh every year, or every other year. Instead of the "continued culture" of sp.a.w.n, that is, inoculating the bricks each succeeding year from the same line of sp.a.w.n, which is, as it were, used over and over again, a return is made each year, or in the alternate years, to the natural or virgin sp.a.w.n, which is obtained from old manure heaps. In this way, the Barter sp.a.w.n[D] is within two to three, or four, generations of the natural sp.a.w.n. The number of generations distant the brick is from the natural sp.a.w.n, depends upon the number of times it may have been multiplied before it is inoculated into the bricks. That is, the natural sp.a.w.n is probably first grown in large beds in order to multiply, to produce a sufficiently large quant.i.ty for the inoculation of the immense number of bricks to be manufactured. For it is likely that a sufficient amount of natural sp.a.w.n could not be obtained to inoculate all the bricks manufactured in one year. If a sufficient amount of the natural or virgin sp.a.w.n could be obtained to inoculate all the bricks of one year's manufacture, this would produce a sp.a.w.n removed only one generation from that of natural sp.a.w.n.

If the natural sp.a.w.n were first grown in beds, and from here inoculated into bricks, this particular brick sp.a.w.n would be removed two generations from the natural sp.a.w.n. So the number of times that successive inoculations are made to multiply the sp.a.w.n, the manufactured products are removed that many generations from the natural sp.a.w.n. Where recourse is had to the natural, or virgin sp.a.w.n only once in two years, the second year's product would then be further removed from the natural sp.a.w.n than the first year's product. Where we know that it is removed but one or a few generations from the natural sp.a.w.n, it is a more desirable kind. For the nearer it is to the natural sp.a.w.n, other things being equal, the more vigorous the mycelium, and the finer will be the mushrooms produced.

The brick sp.a.w.n is sometimes manufactured in this country by growers for their own use, but at present it is manufactured on such a large scale in England that little or no saving is effected by an attempt to manufacture one's own brick sp.a.w.n in this country.

=Flake Sp.a.w.n.=--The flake sp.a.w.n, or "flakes," is commonly known as the French sp.a.w.n, because it is so extensively manufactured in France. It is made by breaking down beds through which the mycelium has run, and before the crop of mushrooms appears. That is, the bed is sp.a.w.ned in the ordinary way. When the mycelium has thoroughly permeated the bed, it is taken down and broken into irregular pieces, six to eight inches in diameter. Thus, the French sp.a.w.n, where the beds are made entirely of horse manure, with no admixture of soil, consist merely of the fermented and cured manure, through which the mycelium has run, the material, of course, being thoroughly dried. This sp.a.w.n may be removed one or several generations from the natural sp.a.w.n.

[Ill.u.s.tration: FIGURE 234.--French sp.a.w.n, or "flakes," ready to plant.]

The French growers depend on natural sp.a.w.n much more than American growers do. The natural sp.a.w.n is collected from old manure heaps. Beds made up in the ordinary way for the cultivation of mushrooms are planted with this. The mycelium is allowed to run until it has thoroughly permeated the manure. These beds are broken down and used to sp.a.w.n the beds for the crop. In this case the crop would be grown from sp.a.w.n only one generation removed from the virgin sp.a.w.n. If a sufficient amount of natural sp.a.w.n could not be obtained, to provide the amount required one generation old, it might be run through the second generation before being used. From the appearance of any sp.a.w.n, of course, the purchaser cannot tell how many generations it is removed from the natural sp.a.w.n.

For this quality of the sp.a.w.n one must depend upon the knowledge which we may have of the methods practiced by the different producers of sp.a.w.n, if it is possible even to determine this.

Sp.a.w.nING THE BEDS.

The beds for growing the mushrooms having been made up, the sp.a.w.n having been selected, the beds are ready for planting whenever the temperature has been sufficiently reduced and the material is properly cured. It is quite easy to determine the temperature of the beds, but it is a more difficult problem for the inexperienced to determine the best stage in the curing of the material for the reception of the sp.a.w.n. Some growers rely more on the state of curing of the manure than they do upon the temperature. They would prefer to sp.a.w.n it at quite a low temperature, rather than to sp.a.w.n at what is usually considered an optimum temperature, if the material is not properly cured. The temperature at which different treatises and growers recommend that the bed should be sp.a.w.ned varies from 70 to 90 F. Ninety degrees F. is considered by many rather high, while 70 F. is considered by others to be rather low; 80 to 85 is considered by many to be the most favorable temperature, provided of course the other conditions of the bed are congenial. But some, so far as temperature is concerned, would prefer to sp.a.w.n the bed at 75 F. rather than at 90, while many recommend sp.a.w.ning at 70 to 75. In some cases, I have known the growers to allow the temperature of the beds to fall as low as 60 before sp.a.w.ning, because the material was not, until that time, at the proper state of curing. Yet an experienced grower, who understands the kind of sp.a.w.n to plant in such a bed, can allow the temperature to go down to 60 without any very great risk.

Fresh sp.a.w.n in an active state, that is, sp.a.w.n which is in a growing condition, as may be obtained by tearing up a bed, or a portion of one, through which the sp.a.w.n has run, is better to plant in a bed of such low temperature. Or, a bed of such low temperature, after sp.a.w.ning, might be "warmed up," by piling fresh horse manure over it loosely for a week or ten days, sufficient to raise the temperature to 80 or 90.

[Ill.u.s.tration: FIGURE 235.--Pieces of brick sp.a.w.n ready to plant.]

When the brick sp.a.w.n is used, the method of planting varies, of course, with the methods of different operators. Some break the bricks into the desired size and plant the pieces directly in the bed, without any special preparation. The brick is broken into pieces about two or three inches in diameter. Some recommend breaking the brick of the ordinary size into about twelve pieces, some into nine pieces, so the custom varies with different operators. These pieces are planted from seven to nine inches apart in the bed. For example, if they are to be planted nine inches apart in the bed, holes are made, either with the hand or with some instrument, by pressing the material to one side sufficiently to admit of the piece of sp.a.w.n being pressed in tightly. These openings are made, say, the first row on one side of the bed, about four and one-half inches from the side, and nine inches apart in the row. The second row is made nine inches from the first row, and so on. The pieces of sp.a.w.n are inserted in the opening in the bed, and at a slight distance, two to three inches, below the surface. Some, however, insert the piece of sp.a.w.n just at the level of the bed, the opening being such that the piece of sp.a.w.n pressed into the opening is crowded below in place, and the surrounding material fits snugly on the sides. Thus, when the bed is sp.a.w.ned, the pieces may be a slight distance below the top of the bed when they can be covered by some material, or in other cases, where the operator varies the method, they would lie just at the surface of the bed.

The bed is now firmed down according to the custom of the operator, either tamped down with some instrument very firmly, or by others, with the back of the fork or other similar instrument, the bed is made firm, but not quite so hard. The object in firming it down after sp.a.w.ning is to make the surface of the bed level, and also to bring the material in the bed very closely in touch on all sides with the sp.a.w.n with which it is impregnated.

[Ill.u.s.tration: FIGURE 236.

Piece of Natural Sp.a.w.n.

Piece of French Sp.a.w.n.

"Flakes" many generations old, "running out."]

Some growers follow the method of giving the sp.a.w.n some little preparation before putting it into the bed. This preparation varies with different operators. Its object, however, is to slightly moisten the dry sp.a.w.n, and perhaps, also, to very slightly start the growth. To accomplish this, some will cover the bricks, before breaking them, with fresh horse manure, and allow this to remain several days, so that the warmth and moisture generated here penetrate the material and soften somewhat the brick. Some pile it in a room or compartment where there is little moisture, until the bricks are permeated to some extent with the moisture, so that they are a little easier broken. They should not, under any circ.u.mstances, be wet or soft in the sense of having absorbed an excess of water, nor should they be stored for any length of time where they will be damp. Still others break the bricks into the desired pieces and place these directly on the top of the bed, at the place where they wish to plant the piece of sp.a.w.n. They are left here for two or three days on the surface of the beds. These pieces absorb some moisture and take up some warmth from the bed. Then they are planted in the ordinary way.

=Sp.a.w.ning with Flake Sp.a.w.n, or Natural Sp.a.w.n.=--In the use of the flake or natural sp.a.w.n, the planting is accomplished in a similar way, but larger pieces of the sp.a.w.n are used, two or three times the size of the pieces of brick employed. Some use a large handful. In some few cases, the growers use a flake sp.a.w.n from their own crop. That is, each year a few beds are sp.a.w.ned from material which has been kept over from the previous season. This is often kept in boxes, in cool places, where it does not thoroughly dry out. In this way, the sp.a.w.n is used over and over again, until it becomes much less vigorous than natural sp.a.w.n, or a sp.a.w.n which is only one or only a few generations distant from the natural sp.a.w.n. This is seen in the less certainty with which the sp.a.w.n runs through the bed, in the smaller crop of mushrooms, and their gradual deterioration in size. Some few practice the method of breaking down the bed after the crop has been nearly gathered, using this weak sp.a.w.n to inoculate fresh beds. This practice is objectionable for the same reason that long cultivated sp.a.w.n is objectionable.

=Soiling the Beds.=--After the beds have been planted with the sp.a.w.n, the next thing is to soil them. That is, the manure in the bed is covered with a layer of loam soil, or garden soil, to the depth of two inches, then spread evenly over the bed, leveled off, and tamped down, though not packed too hard, and the surface is smoothed off. The time at which the soiling is done, varies also with different operators. Some soil immediately after planting the sp.a.w.n. Others believe that the sp.a.w.n will most certainly fail to run if the beds are soiled immediately after planting. These operators wait two or three weeks after the sp.a.w.n has been planted to soil it. Others wait until the temperature of the bed has fallen from 80 or 85 at the time of sp.a.w.ning, to 70 or 60 F.

Soiling at this temperature, that is, at 60 or 70 F., probably prevents the rapid cooling down of the bed, and it is desirable to soil, at least at this temperature, for that purpose. When the beds are soiled, they are then left until the crop is ready to gather. Some operators give no further attention to the beds after soiling, other than to water the beds, if that becomes necessary. It is desirable to avoid watering, if the bed can be kept at the right state of moisture without. In watering the beds while the sp.a.w.n is running, there is danger of killing the young sp.a.w.n with the water. Wherever it is necessary, however, if the material in the bed becomes too dry, lukewarm water should be used, and it should be applied through a fine rose of a watering pot.

While some operators after soiling the bed give no further care to it until the bed is bearing, others cover the beds with some litter, in the form of straw or excelsior. This is done for the purpose of conserving the moisture in the bed, and especially the moisture on the surface of the bed. Sometimes where there is a tendency for the material in the bed to become too dry, this litter on the surface r.e.t.a.r.ds the loss of moisture. Also, the litter itself may be moistened and the bed can absorb some moisture in this way, if it is desirable to increase the moisture content of the bed slightly.

When the sp.a.w.n has once run well through the bed, watering can be accomplished with less danger of injury, yet great care must be used even now. The sp.a.w.n will run through a bed with a somewhat less moisture content in the material than is necessary for drawing off the crop of mushrooms, though, of course, the sp.a.w.n will not run if the bed is too dry. The only way to see if the sp.a.w.n has run satisfactorily is to open up the bed at one or two points to examine the material, opening it up slightly. If the sp.a.w.n has run well, a very delicate white "fiber," the mycelium, can be seen penetrating all through the material. This handful can be replaced in the bed, packed down, and the soil covered over and firmed again at this point.

When the mushrooms begin to appear, if the bed is a little dry, it should be watered from time to time through the fine rose of a watering pot. Lukewarm water should be used. Nearly all growers water the beds during the picking of the crop, or during the period of gathering the crop. At the first few waterings, water should not be sprinkled on the beds to wet them entirely through. Enough water is applied to diffuse a short distance only through the upper surface of the bed. At the next watering, several days later, the moisture is carried further down in the bed, and so on, through the several weeks, or months, over which the harvesting season extends. The object of thus gradually moistening the bed from above, is to draw the crop from the sp.a.w.n at the surface of the bed first, and then, as the moisture extends downward, to gradually bring on the crop from the "fiber" below.

=Gathering the Mushrooms.=--In artificial cultivation, the mushrooms usually formed are very near, or on, the surface of the bed. In the case of the meadow or pasture mushrooms, they are formed further below the surface. This is probably due to the fact that the conditions under which the mushrooms grow in cultivation are such that the surface of the bed is more moist, and is less subject to variations in the content of moisture, than is the surface of the ground in pastures. Although there may be abundant rains in the fields, the currents of air over the surface of the ground, at other times, quickly dries out the upper layers of the soil. But indoors the mycelium often runs to the surface of the bed, and there forms the numerous pinheads which are the beginnings of the mushrooms. The beds at this stage often present numerous cl.u.s.ters of the mycelium and these minute pinheads crowded very closely together. Hundreds or perhaps thousands of these minute beginnings of mushrooms occur within a small s.p.a.ce. There are very few of these, however, that reach the point of the mature mushroom. Few only of the pinheads grow to form the b.u.t.ton, and the others abort, or cease to grow. Others are torn out while the larger ones are being picked.

The time at which the mushrooms are picked varies within certain limits, with the different growers. Most cultivators, especially those who grow the mushrooms in houses, consider 60 F. the desirable temperature for the growth of mushrooms, that is, at a room temperature of 60 (while some recommend 57). The temperature of the beds themselves will be slightly above this. Under these conditions, that is, where the mushrooms are grown at a room temperature of about 60, they open very quickly. It is necessary here to gather the mushrooms before they open, that is, before the veil on the under surface breaks to expose the gill surface. This practice is followed, of course, within certain limits. It is not possible in all cases, to pick every mushroom before the veil breaks. They are collected once a day usually. At the time of collection all are taken which are of suitable size. Many of them may not yet have opened. But in the case of some of the older or more rapidly growing ones, the veil may have broken, although they have not expanded very much.