Mushrooms may be, and are, grown to perfection in many less ambitious structures than the mushroom-house proper. Any species of outhouse will do for the autumn and early winter crops. One of the best crops I have ever seen was grown in a dry and unused coach-house. Mr. Robert Fish grows all his crops in a long, low, rude thatched shed, open in front—the beds flat, in a continuous line against a wall, and enclosed by a low board. Mr. Cuthill, who wrote on mushrooms, and who used to grow them very well, grew his in rude sheds placed against walls. It matters not in the least if the shed be open or ventilated here and there, especially for autumn crops, as I have seen admirable crops in low outhouses searched by every gust, and not heated by flues. The beds in these should always be covered with hay. Mushrooms may be grown in cellars; but cellars being commonly under houses, they are not exactly the places to which people like to convey the materials necessary for the making of mushroom-beds. Where they occur away from a dwelling-house, this objection will not hold good. In some cases it might be obviated by making the beds in rough boxes, say 3½ ft. long by 1½ ft. wide, and afterwards introducing them into the cellar. Railway or other arches, or any dry and empty structures, may be used for mushroom-growing.

“The construction,” says Mr. William Ingram, of Belvoir, in a letter to the Field, “of efficient mushroom-houses is sufficiently understood by most of our hothouse-builders and by gardeners; but the economical adaptation of places which already exist is a matter which may with the greatest advantage be discussed, as there are hundreds of persons about whose establishments may be found outhouses, cellars, quarries, or sheds, capable of conversion into mushroom-houses, who would be very glad to be taught the method of growing mushrooms, and to have the simple principles that should govern the construction of mushroom-houses explained.

“There are few large farmsteads that are without an unconsidered place which could be readily adapted for the purpose of growing mushrooms; and farmers possess the material at hand, horse manure, which would not suffer great deterioration if employed in first raising a crop of mushrooms. Country brewing establishments have equal conveniences and opportunities. By relating the means by which I have been for several years able to raise large quantities of excellent mushrooms, in a place originally but ill adapted for the purpose, I may induce some of those persons who desire the luxury of what Soyer called ‘the Pearl of the Fields,’ to turn their attention to the subject of their growth.

“I had a large, open, airy shed at command, but it was liable to be affected by changes in the weather, and was altogether too draughty and cold in winter, and too hot in summer. I built within this shed, with rough fir boards, an inner shed, 18 ft. long, 6 ft. wide, and 8 ft. in height; two receptacles for beds were formed, one on the floor, the other above it: and to give the requisite heat in winter, I passed a flue, formed of 9-in. socket pipes, through the house; with this I can always command an adequate amount of heat. The material of which the beds are formed is chiefly droppings, collected from an enclosed and covered exercise ground. These droppings are trampled by the horses, and mixed with straw broken up with the manure by the passage of the horses.

“When first collected it is piled up in a large heap, in a perfectly dry state, and when wanted for the bed is thrown out, sprinkled with water, and fermented for about a week; while hot, it is taken to the house, and as it is thrown in is mixed with a small quantity of soil of a loamy character, and a barrow-load of leaf soil. It is then pressed into as compact a mass as possible by a rammer or mallet, building it up until it forms a bed 10 in. thick in front and 20 in. at the back. After a bed formed of this description of materials has been thus put together, rapid fermentation takes place; and when the most violent fermentative action has passed, and a temperature of 80° is found in the bed, spawn is put into it by means of a dibber. I employ brick spawn obtained from good makers, but, to vary and possibly prolong the period of production, I introduce a certain quantity of spawn saved from old beds. This is longer in its development than the made spawn, and appears as a subsidiary crop. After the bed is spawned, a covering of compact loamy soil is spread on the surface, 1½ in. to 2 in. in thickness, and well beaten upon it so as to form a smooth and hard crust. A temperature ranging from 50° to 60° should be maintained in the house. A lower temperature abstracts the heat from the bed more rapidly.

“When the mushrooms begin to exhibit weakness, as after the bed has produced a certain quantity they will do, from the exhaustion of the more stimulating portions of the manure, I find it an excellent practice to administer a sprinkling of water in which a handful of salt has been thrown (that quantity of salt to a three-gallon can). Saltpetre, though in much smaller quantities, is equally valuable given in the same way. The practice I have described relates to the winter cultivation of mushrooms.”

Many instances of perfect success like the preceding could be quoted. Here is one from Mr. W. P. Ayres:—

“You will be glad to hear that we have on the outskirts of this town (Nottingham) a grower of mushrooms (Mr. Cookson, Mansfield Road) who vies with the French growers, especially if the means of growth be taken into consideration. The place he occupies was formerly the pleasure garden of a large hotel, where the proprietor would occasionally, in the summer season, treat his friends and patrons to an al fresco entertainment. For this purpose a range of summer-houses was built, consisting of brick arches, say 12 feet deep, 6 feet wide, and a little more in height. Close adjoining is a small sandstone-rock cellar, which used to serve for drinkables in the summer and potatoes in the winter.

“Some twelve months ago these premises and the house adjoining fell into the occupation of a gardener, who, though he had a licence to the house, fancied he might turn the arches to a better purpose, and hence he devoted them to mushroom beds. As it was necessary that the arches should be closed, a wall about three feet high was built in the rudest manner parallel with their front, but six feet from it, and from that a roof of rough timber was thrown, and covered with asphalted felt. Here, however, was a mistake; for, the building standing due south, when the sun fell upon it the atmosphere became rather ‘tarry’—so much so that the mushrooms refused to grow in it. That wore off after a time, and from a bed not more than thirty yards square the tenant told me he had cut more than 25l. worth of mushrooms. When I saw the beds they might be considered spent, the flush of early youth was over; but still the crop was most wonderful, especially considering the means at command.

“In the rock cellar the small beds were a pavement of splendid mushrooms, many of them as large over as a cheese-plate, and thick in proportion. In the garden is a barn—four walls with a roof over them, the latter so rude that it was only in fair weather that it could be called waterproof. In this place which may be 25 ft. long by 15 ft. wide, two tiers of beds have been put up, the roof has been made waterproof, a common brick flue put through it, and, at the time I saw them, more promising beds could not be desired. Here again, you will perceive expensive appliances are not necessary for the production of mushrooms.”

Stables and like structures offer capital positions in which successful mushroom culture may be carried out with ease.

If it is possible, and we know it is not only possible but easy, to grow mushrooms in boxes a few feet long and a foot or eighteen inches wide, and the same depth, it is clear that there can be no difficulty about growing them in abundance in such a manner as that shown in the accompanying engraving. This mode was actually practised with great success by the Baron Joseph d’Hoogvorst, of Limmel.

The culture was carried out in neatly fitted-up wooden boxes, so arranged that they might be shrouded with canvas curtains as shown in the engraving, so that at first sight one would not suppose that mushroom culture was carried on there. No evil results as regards the creation of an unhealthy atmosphere accompanied the attempt. The beds were formed much in the usual way from the droppings of highly fed horses. Now there can be no doubt that a similar mode of growing mushrooms could be carried out in the stables or some adjacent building in hundreds of places apart from the garden and the gardener altogether. Given the materials and some position, however contracted, in which to carry out the culture, and both these things are surely to be had almost in every place where there is a stable, the rest is so simple that any stableman or boy could carry it out. We know that these individuals, as a class, are not much given to botanical or horticultural studies, but no doubt the prospect of an occasional half-dozen fresh mushrooms on the gridiron would give them most praiseworthy interest in the culture. The only objection to it is, or might be, that once they were at home in the culture, the gardener would be very likely to fall short of materials for his hotbeds. An empty loft, or any other covered structure could be employed as well as the stable or an empty coach-house. Apart altogether from utilizing the walls of the stable, as the Baron did, empty stalls frequently present an opportunity of growing mushrooms in quantity. These remarks apply to stables in cities and towns, as well as in the country; indeed in cities, particularly in London, stable manure is usually so plentiful that it is much easier to obtain and much cheaper than in the country, so that even those in London having suitable places for growing mushrooms, but not keeping horses regularly or at all, could have no difficulty in procuring abundance of materials.

The French often cultivate mushrooms in cellars as well as in the caves described in the next chapter. Preference should be given to a dry warm cellar; it should be as dark as possible, and exposed to no draughts. Beds can be made in cellars in many ways. Those made in the middle should always be formed with two sides, while those against the walls should only be half as thick, on account of their having only one useful side. It is also possible to arrange them on shelves, one above the other. For this purpose strong bars of iron are driven into the walls, upon which are placed shelves of the proper size covered with earth, upon which is formed a bed, that is treated exactly as those made upon the ground. These beds are just as productive as any of the other kinds. They may even be made on the bottoms of casks, which should be at least two feet six in diameter; and they are built up in the shape of a sugarloaf, about three feet in height, and the pieces of spawn are placed an inch and a quarter deep, and sixteen inches apart. A barrel is sawn crossways into two pieces, each forming a tub. Holes are made in the bottom of each, and a thin layer of good soil is spread over them inside. They are then filled with good well-prepared stable manure, just like that used in the case of ordinary mushroom-beds, the different layers of dung in each tub being well pressed down. When the tub is half full, six or seven good pieces of spawn are placed on the surface, and the remainder is piled up with manure, which is well pressed down, the operation being completed by giving to the heap the form of a dome. The tubs thus prepared are placed in a perfectly dark part of a cellar, and eight or ten days afterwards the dung is taken up until the spawn is visible, in order to see whether it has commenced to vegetate and develop little filaments. If the spawn has spread, the surface must be covered with soil, care being taken to use only that which is fresh and properly prepared. In this or any like way there should be no difficulty in growing mushrooms: the boxes or tubs could be filled anywhere, and then carried into the spare cellars, &c. In this way objections against steaming manure might in many cases be got over.

Among the many and various structures in which mushrooms may be grown, but which we rarely see utilized for that purpose, may be mentioned all kinds of greenhouses, stoves, pits, and frames. Some of the best crops I have ever seen were in cold greenhouses almost too ruinous to grow anything else. In mid-winter the floors of all houses in which a genial temperature is kept up for forcing or other purposes, offer excellent positions for producing mushrooms quickly and abundantly. Small ridge-like beds might be made on the floor of these, and, with the genial temperature usually kept up in such places, would probably come into bearing a month or so after being spawned. How often, for example, do we notice the floors of large vineries, in mid-winter or very early spring, quite bare, especially after the vines are started. Now just at that season the genial heat that would be given off from the slightly fermenting materials used for the mushroom-bed is that which would be most congenial to the tender breaking vines, and with a little attention in this way a first-rate crop of mushrooms could always be gathered from the early vinery, and in houses where no artificial heat was applied they could also be grown abundantly. A covering of hay would, however, be necessary in cold houses in mid-winter, to prevent excessive variation of the temperature, and also in spring and summer to prevent excessive drying or scorching of the beds by a hot sun. I have even seen excellent crops grown on the floor in an old lean-to house, the beds covered with a foot or so of hay, occasionally sprinkled with water to prevent excessive heat on the surface of the bed. In small places where every foot of space in the glass-house is likely to be occupied with plants, it is not easy to carry out the foregoing suggestions, but even if a small early vinery were occupied with plants, it would be desirable and practicable to introduce a series of rough boxes devoted to mushroom culture.

Apart from empty greenhouses altogether, the space beneath the stages in numbers of glass-houses of every type may be utilized for the production of mushrooms. These positions are usually unoccupied, occasionally they are used for storing fuchsias, &c. in winter, but very seldom are they turned to so good account as they might be in the way I recommend. The stage in the small greenhouse is frequently elevated so that there is plenty of room to get beneath it: if at the back or end there is no way of walking readily under the stage, an opening should be made. The only difficulty that could possibly occur would arise from the drip from the plants on the stage above. This, however, can be easily guarded against by spreading a piece of tarpaulin or oil-canvas over the bed or beds. With beds properly made, a coat of dry hay or litter, and a piece of tarpaulin, every owner of anything in the shape of a greenhouse with a stage in it may grow mushrooms throughout the autumn, winter, and spring months, and even in summer by keeping the surface of the hay or litter moist. Of course, if there be room for but one bed, a succession cannot be kept up, and in this case a bed should be made in autumn, which, if well managed, should be in full bearing for a month or six weeks before and after Christmas. There are, however, numerous spaces such as those alluded to where there is room to make a succession of beds. No person having but one greenhouse need fear much or any inconvenience from the odour of the manure—at least, not after the beds are earthed. The couple of inches of soil over the manure would absorb any vapour given off by the bed.

Wherever the cultivation of cucumbers or melons in pits or frames is carried out, nothing can be easier than to grow large crops of mushrooms after the melons, &c. are cleared away. The spawn may be inserted over the surface of the little mounds usually made for the reception of the young melon plants, and also over the remaining surface of the beds which are generally covered with a few inches of earth. After the melons have done bearing and the haulm is cleared away, the spawn will usually be found to have spread through the deep mass of earth in the beds. As little or no water is given or required while the melons are ripening, a good soaking of tepid water will generally be necessary to encourage the mushrooms to start into profuse bearing. If the season and situation be mild and warm, the lights may be taken off; and if the sun be very strong, the beds may be shaded with canvas or mats. If the season be late and cold it will, on the other hand, be desirable to keep on the lights, and even to cover them in cold weather.