Chapter XX: Cultivation of Mushrooms (2)

One not accustomed to the quality of spawn 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 quantity of the "fiber." Since the spawn remains in good condition for several years, there is usually no danger in the use of spawn which may be one or two years old. But it does deteriorate to some extent with age, and young spawn is therefore to be preferred to old spawn, provided the other desirable qualities are equal. Those who attempt to cultivate mushrooms, and depend on commercial or manufactured spawn, should see to it that the spawn 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 spawn should be called for. There is no more reason why a grower should accept a worthless spawn from his seedsman than that he should accept "addled" eggs from his grocer. In this business, that is, the manufacture and sale of spawn, 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 spawn, that is, those manufactured by certain houses, which rank very high among those who know the qualities and the value of good spawn. Some large growers send direct to the manufacturer for their spawn, and where it is to be obtained in large quantities this is a desirable thing to do, since the cost is much less. Where obtained from seedsmen in large quantities, the prices are much lower than where small quantities are purchased. One of these brands of spawn, the Barter spawn, is for sale by several different dealers, by Mr. H. E. Hicks, Kennett Square, Pa., by Henry F. Michell, 1018 Market street, Philadelphia, and by Henry Dreer, 724 Chestnut street, Philadelphia. Another brick spawn, 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 spawn manufactured expressly for their trade.

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

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

The brick spawn 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 spawn in this country.

=Flake Spawn.=--The flake spawn, or "flakes," is commonly known as the French spawn, 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 spawned 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 spawn, 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 spawn may be removed one or several generations from the natural spawn.

The French growers depend on natural spawn much more than American growers do. The natural spawn 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 spawn the beds for the crop. In this case the crop would be grown from spawn only one generation removed from the virgin spawn. If a sufficient amount of natural spawn 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 spawn, of course, the purchaser cannot tell how many generations it is removed from the natural spawn. For this quality of the spawn one must depend upon the knowledge which we may have of the methods practiced by the different producers of spawn, if it is possible even to determine this.

SPAWNING THE BEDS.

The beds for growing the mushrooms having been made up, the spawn 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 spawn. Some growers rely more on the state of curing of the manure than they do upon the temperature. They would prefer to spawn it at quite a low temperature, rather than to spawn 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 spawned 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 spawn the bed at 75° F. rather than at 90°, while many recommend spawning 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 spawning, because the material was not, until that time, at the proper state of curing. Yet an experienced grower, who understands the kind of spawn to plant in such a bed, can allow the temperature to go down to 60° without any very great risk. Fresh spawn in an active state, that is, spawn which is in a growing condition, as may be obtained by tearing up a bed, or a portion of one, through which the spawn has run, is better to plant in a bed of such low temperature. Or, a bed of such low temperature, after spawning, 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°.

When the brick spawn 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 spawn 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 spawn 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 spawn just at the level of the bed, the opening being such that the piece of spawn pressed into the opening is crowded below in place, and the surrounding material fits snugly on the sides. Thus, when the bed is spawned, 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 spawning 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 spawn with which it is impregnated.

Piece of Natural Spawn.
Piece of French Spawn.
"Flakes" many generations old, "running out."]

Some growers follow the method of giving the spawn some little preparation before putting it into the bed. This preparation varies with different operators. Its object, however, is to slightly moisten the dry spawn, 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 circumstances, 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 spawn. 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.

=Spawning with Flake Spawn, or Natural Spawn.=--In the use of the flake or natural spawn, the planting is accomplished in a similar way, but larger pieces of the spawn 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 spawn from their own crop. That is, each year a few beds are spawned 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 spawn is used over and over again, until it becomes much less vigorous than natural spawn, or a spawn which is only one or only a few generations distant from the natural spawn. This is seen in the less certainty with which the spawn 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 spawn to inoculate fresh beds. This practice is objectionable for the same reason that long cultivated spawn is objectionable.

=Soiling the Beds.=--After the beds have been planted with the spawn, 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 spawn. Others believe that the spawn will most certainly fail to run if the beds are soiled immediately after planting. These operators wait two or three weeks after the spawn has been planted to soil it. Others wait until the temperature of the bed has fallen from 80° or 85° at the time of spawning, 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 spawn is running, there is danger of killing the young spawn 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 retards 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 spawn 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 spawn 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 spawn will not run if the bed is too dry. The only way to see if the spawn has run satisfactorily is to open up the bed at one or two points to examine the material, opening it up slightly. If the spawn 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 spawn 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 clusters 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 space. There are very few of these, however, that reach the point of the mature mushroom. Few only of the pinheads grow to form the button, 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.

Some follow the method of having the fireman, on his round at night, when he looks after the fires in the heating room, gather the mushrooms. He passes through all parts of the house and picks the mushrooms which are of suitable size. These are gathered by grasping a single mushroom by the cap, or where there is a cluster of mushrooms close together, several are taken in the hand. The plant is twisted slightly to free the stem from the soil, without tearing it up to any great extent. They are thrown in this condition into baskets. The collector then takes them to the packing room, and the following morning the plants are trimmed, that is, the part of the stems to which the earth is attached is cut away, the plants are weighed, put in baskets, and prepared for the markets. In other cases, the mushrooms are gathered early in the morning, in the same way, taken to the packing room, where the lower part of the stem is cut away, the plants are weighed, placed into the baskets and shipped to market.

In some of the caves, or abandoned mines, which I have visited, where the mushrooms are grown on a large scale, the practice in picking the mushrooms varies somewhat from that just described. In the first place, the mushrooms are allowed to stand on the bed longer, before they are picked. They are rarely, if ever, picked before they open. Mushrooms may be quite large, but if they have not opened, they are not picked. Very frequently, the plant may open, but, the operator says, it is not open enough. It will grow more yet. The object of the grower, in this case, is to allow the mushrooms to grow as long as it is possible, before picking, for the larger the mushroom, the more water it will take from the bed, and the more it weighs. This may seem an unprofessional thing for a grower to do, and yet it must be remembered that a large water content of the mushroom is necessary. The mushrooms grown in these mines are very firm and solid, qualities which are desired, not only by the consumer, but are desirable for shipment. These mushrooms are much thicker through the center of the cap than those usually grown in houses at a room temperature of 60° F. For this reason, the mushrooms in these caves spread out more, and the edges do not turn up so soon. Since the cap is so thick and firm at the center, it continues to grow and expand for some little time after having opened, without turning up on the edges, and without becoming black and unsightly underneath. These large and firm mushrooms are not only desirable for their shipping qualities, but also, if they are not too large, they are prized because they are of such a nice size for broiling.

It is quite likely that one of the important conditions in producing mushrooms of this character is the low temperature of the mine. The temperature here, in July and August, rises not higher than 58° F., that is, the room temperature of the mines; while in the winter it falls not lower than 52°. The growth of mushrooms, under these conditions, may not be quite so rapid as in a house maintaining a room temperature of 60°. The operator may not be able to grow so many crops from the same area, during the same length of time; but the very fact that this low temperature condition retards the growth of the mushrooms is perhaps an important item in producing the firm and more marketable product, which can be allowed to grow longer before it is picked. It is possible, also, that another condition has something to do with the firmness and other desirable qualities of these mushrooms. It is, perhaps, to be found in the fact that natural spawn is largely used in planting the beds, so that the spawn is more vigorous than that which is ordinarily used in planting, which is several or many generations distant from the virgin condition.

The methods of picking in this mine differ, also, from those usually employed by growers of mushrooms. The mushrooms are pulled from the bed in the same way, but the operator carries with him two baskets and a knife. As fast as the mushrooms are pulled, and while they are still in hand, before the dirt can sift upon the other mushrooms, or fall in upon the gills of those which are open, the lower part of the stem is cut off. This stem end is then placed in one basket, while the mushrooms which have been trimmed are placed in another basket. In cutting off the stems, just enough is cut to remove the soil, so that the length of the stem of the mushroom varies. The mushrooms are then taken to the packing room in the cleanest possible condition, with no soil scattering therefrom or falling down among the gills, as occurs to a greater or lesser extent where the mushrooms are picked and thrown indiscriminately into baskets.

=Packing the Mushrooms.=--In the packing room the mushrooms are prepared for shipment to market. The method at present usually employed is to ship them in baskets. The baskets vary in size, according to the market to which the mushrooms are to be shipped. They hold from three, to four, five, six, or ten pounds each. The larger baskets are only used where the mushrooms are shipped directly to the consumers. When the customer requires a large number of mushrooms, they can be shipped in these larger baskets. Where they are shipped to commission merchants, and the final market is not known to the packer, they are usually packed in small baskets, three to four or five pounds. The baskets are sometimes lined with paper; that is, at the time of the packing the paper is placed in the basket, one or two thicknesses of paper. The number of layers of paper depends somewhat upon the conditions of transportation. The greater amount of paper affords some protection from cold, in cold weather, and some protection from the evaporation of the moisture, in dry weather. When the basket is filled with the required quantity of mushrooms, which is usually determined first by weight, the surplus paper is folded over them. This is covered in most cases by thin board strips, which are provided for basket shipment of vegetables of this kind. In some cases, however, where shipped directly to customers so that the baskets soon reach their destination, additional heavy paper, instead of the board, may be placed over and around the larger part of the basket, and then tied down neatly with cord.

=Placing the Mushrooms in the Basket.=--Some growers do not give any attention to placing the mushrooms in the baskets. The stems are cut off in the packing room, they are thrown into the weighing pan, and when the beam tips at three, or four, or five pounds, as the case may be, the mushrooms are emptied into the baskets, leveled down, and the baskets closed for shipment. Others use more care in the packing of the mushrooms; especially is this the case on the part of those who pick the mushrooms when they are somewhat larger and more open, though the practice of placing the mushrooms in a basket is followed even by those who pick before the mushrooms are open. In placing them, one mushroom is taken at a time and put stem downward into the basket, until the bottom is covered with one layer, and then successive layers are placed on top of these. The upper layers in the basket then present a very neat and attractive appearance. In thus placing the mushrooms in the basket, if there are any mushrooms which are quite large, they are placed in the bottom. The custom of the operator here is different from that of the grower of apples, or of other fruit, where the larger and finer samples are often placed on top, the smaller ones being covered below. It is a curious fact, however, that this practice of placing the largest mushrooms below in the basket is due to the fact that usually the larger mushrooms are not considered so marketable.

There are several reasons why the larger mushrooms are not considered so desirable or marketable as the medium-sized or smaller ones. In the first place, the larger mushrooms, under certain conditions, especially those grown in house culture at a comparatively high temperature, are apt to be very ripe, so that the gills are black from over-ripe spores, and are thus somewhat unsightly. Those grown at a lower temperature, as is the case in some mines, do not blacken so soon, and are therefore apt to be free from this objection. Another objection, however, is on the part of the restaurant owner where mushrooms are served. In serving the mushrooms broiled on toast, the medium-sized one is more desirable from the standpoint of the restaurant owner, in that two medium-sized ones might be sufficient to serve two persons, while one quite large one, weighing perhaps the same as the two medium ones, would only be sufficient to serve one person at the same price, unless the large mushroom was cut in two. If this were done, however, the customer would object to being served with half a mushroom, and the appearance of a half mushroom served in this way is not attractive.

=Resoiling.=--Once or twice a week during the harvesting period all loose earth, broken bits of spawn, free buttons, etc., should be cleaned out where the mushrooms have been picked. These places should be filled with soil and packed down by hand. All young mushrooms that "fog off" should be gathered up clean. Some persons follow the practice of growing a second crop on the same bed from which the first crop has been gathered. The bed is resoiled by placing about two inches of soil over the old soil. The bed is then watered, sometimes with lukewarm water to which a small quantity of nitrate of soda has been added. The large growers, however, usually do not grow a second crop in this way, but endeavor to exhaust the material in the bed by continuous growth.

=Use of manure from beds which have failed.=--Manure in which the spawn has failed to run is sometimes removed from the bed and mixed with fresh manure, the latter restoring the heat. If the manure was too wet, the moisture content can now be lessened by the use of dry soil.

=Cleaning house to prepare for successive crops.=--When the crop is harvested, all the material is cleaned out to prepare the beds for the next crop. The material is taken out "clean," and the floors, beds, walls, etc., swept off very clean. In addition, some growers whitewash the floors and all wood-work. Some whitewash only the floors, depending on sweeping the beds and walls very clean. Still others whitewash the floors and wash the walls with some material to kill out the vermin. Some trap or poison the cockroaches, wood-lice, etc., when they appear. Some growers who succeed well for several years, and then fail, believe that the house "gets tired," as they express it, and that the place must rest for a few years before mushrooms can be grown there again. Others grow mushrooms successfully year after year, but employ the best sanitary methods.

=Number of crops during a year.=--In caves or mines, where the temperature is low, the beds are in process of formation and cropping continuously. So soon as a bed has been exhausted the material is cleaned out, and new beds are made as fast as the fresh manure is obtained. In houses where the mushrooms cannot be grown during the summer, the crops are grown at quite regular periods, the first crop during fall and early winter, and the second crop during spring. Some obtain the manure and ferment it during August and September, spawning the beds in September and October. Others begin work on the fermentation of the manure in June or July, make up the beds in July and August, spawn, and begin to draw off the crop somewhat earlier. The second crop is prepared for whenever the first one is drawn off, and this varies even in the experience of the same grower, since the rate of the running of the spawn varies from time to time. Sometimes the crop begins to come four or five weeks from the time of planting the spawn. At other times it may be two or three months before the spawn has run sufficiently for the crop to appear. Usually the crop begins to come on well in six to eight weeks. The crop usually lasts for six weeks to two months, or longer.

=Productivity of the beds.=--One pound of mushrooms from every two square feet of surface is considered a very good crop. Sometimes it exceeds this, the beds bearing one pound for every square foot, though such a heavy yield is rare. Oftener the yield is less than half a pound for a square foot of surface.

=Causes of failure.=--The beginner should study very carefully the conditions under which he grows his crops, and if failure results, he should attempt to analyze the results in the light of the directions given for the curing of the manure, its moisture content, "sweetness," character of the spawn, temperature, ventilation, etc. While there should be good ventilation, there should not be drafts of air. A beginner may succeed the first time, the second or third, and then may fail, and not know the cause of the failure. But given a good spawn, the right moisture content of the material at time of planting and running of the spawn, the sweet condition, or proper condition of the curing of the manure, proper sanitary conditions, there should be no failure. These are the most important conditions in mushroom culture. After the spawn has run and the crop has begun to come, the beds have been known to freeze up during the winter, and in the spring begin and continue to bear a good crop. After the spawn has run well, beds have accidentally been flooded with water so that manure water would run out below, and yet come on and bear as good a crop as adjoining beds.

=Volunteer mushrooms in greenhouses.=--Volunteer mushrooms sometimes appear in greenhouses in considerable quantity. These start from natural spawn in the manure used, or sometimes from the spawn remaining in "spent" mushroom beds which is mixed with the soil in making lettuce beds, etc., under glass. One of the market gardeners at Ithaca used old spawn in this way, and had volunteer mushrooms among lettuce for several years. In making the lettuce beds in the autumn, a layer of fresh horse manure six inches deep is placed in the bottom, and on this is placed the soil mixed with the old, spent mushroom beds. The following year the soil and the manure at the bottom, which is now rotten, is mixed up, and a fresh layer of manure is placed below. In this way the lettuce bed is self-spawned from year to year. About every six years the soil in the bed is entirely changed. This gardener, during the winter of 1900--1, sold $30.00 to $40.00 worth of volunteer mushrooms. Another gardener, in a previous year, sold over $50.00 worth.

=Planting mushrooms with other vegetables.=--In some cases gardeners follow the practice of inserting a forkful of manure here and there in the soil where other vegetables are grown under glass, and planting in it a bit of spawn.

=Mushroom and vegetable house combined.=--Some combine a mushroom house and house for vegetables in one, there being a deep pit where several tiers of beds for mushrooms can be built up, and above this the glass house where lettuce, etc., is grown, all at a temperature of about 60° F.

THREE METHODS SUGGESTED FOR GROWING MUSHROOMS IN CELLARS AND SHEDS.

=First Method.=--Obtain fresh stable horse manure mixed with straw
used in bedding the animals. Shake it out, separating the coarse
material from the droppings. Put the droppings in a pile two to
three feet deep. Pack down firmly. When the heat rises to near 130°
F., turn and shake it out, making a new pile. Make the new pile by
layers of manure and loam soil, or rotted sod, one part of soil to
eight or nine parts of manure. Turn again when the heat rises to
near 130° F., and add the same amount of soil. When the temperature
is about 100° F., the material is ready for the beds.

=Preparing the beds.=--Make the beds as described under the
paragraph on pages 250--253, or use boxes. Place the coarse litter
in the bottom three to four inches deep. On this place three to
four inches of the cured material, pack it down, and continue
adding material until the bed is ten to fifteen inches deep. Allow
the beds to stand, covering them with straw or excelsior if the air
in the cellar or shed is such as to dry out the surface.

Test the moisture content according to directions on page 255.

Watch the temperature. Do not let it rise above 130° F. When it is
down to 90° F. or 70° F., if the manure has a "sweetish" or
"mushroomy" smell it is ready to spawn.

Spawn according to directions on page 263.

Soil according to directions on page 266; cover bed with straw or
excelsior.

=Second Method.=--Use horse droppings freed from the coarser
material. Proceed as in _first_ method.

=Third Method.=--Use horse droppings freed from coarser material.
Pile and _pack firmly_. Do not let temperature rise above 130° F.
When it has cooled to 100° F., make up the beds, at the same time
mixing in an _equal quantity_ of rich loam or rotted sod. Spawn in
a day or two.

In beginning, practice on a small scale and study the conditions
thoroughly, as well as the directions given in this chapter.

FOOTNOTES:

[D] I have not learned the history of the other kinds of spawn referred to above.