No. 7. DEPARTMENT OF AGRICULTURE. 529 



manure aud soil mixed together. After the bricks are made into 

 shape, and are dried sufficiently, a small piece of spawn is placed in 

 the center of each and the hole is closed up with a piece of the same 

 material of which the brick is made. A bed of horse manure is pre- 

 pared as for a hot bed. The bricks are piled upon it, but not too 

 closely, and are then coA'ered up. The moisture and heat from the 

 manure will start the spawn to grow or run through the bricks. 

 "When this process has gone far enough, the bricks are allowed to 

 cool off and dry, and further growth is stopped until they are to be 

 used for producing a crop. 



The manufacture of spawn is regarded as a very particular busi- 

 ness requiring great skill and care. The French make and sell 

 what is called flake spawn but it is not much used in this country. 

 It is light, and comes in large strawy flakes. There is an American 

 spawn of very recent introduction which is now used to some extent. 

 It seems likely that it may come into general use, as excellent re- 

 sults were obtained from it during the past season. This American 

 spawn is made by taking pieces of the mushroom itself for propa- 

 gating purposes, and it is claimed that the manufacturers can by 

 this method produce and propagate any particular strain, and that 

 by selecting fine specimens for the purpose, they can make a spawn 

 that will produce mushrooms like the parent stock. 



Virgin spawn is that which is obtained from the fields or manure 

 heaps, and is supposed to come from the spores. It is more vigor- 

 ous than made spawn, aud manufacturers endeavor to get it to use 

 in making the spawn which they sell. 



Mushrooms grow in all temperate climates in the world, but they 

 will not grov\' where it is either too cold or too hot. They may be 

 grown in houses built for their cultivation, in house cellars, barn 

 cellars, under the carnation benches in greenhouses, in caves or in 

 any other place where the temperature and moisture can be con- 

 trolled aud kept about uniform and at the proper degree. 



A common plan for houses is about as follovv^s: 100 feet long, IS 

 feet wide and 6 feet to the eaves and with an even span roof. This 

 will allow three beds, 3 and ^ feet wide on each side, and four beds 

 7 feet wide in the center, and two alleys, 2 feet wide, to give room 

 for picking the crop, putting in the manure and taking it out, after 

 the cropping season is over. The entire bed surface of such a house 

 would be 4,900 square feet, and would require about 100 tons of 

 manure costing f 1.25 per ton exclusive of freight and 1,200 pounds 

 of spawn costing 6 cents a pound. Mushroom houses generally 

 have a cellar of 2 or 3 feet dug out, and the dirt is also banked up 

 around the house on the outside. This tends to make it easier to 

 keep as even temperature which is a very important consideration. 



Horse manure from the cities is the kind generally used. It 

 should be free from any other matter and not too strawy. It is 

 put in ricks as hauled from the car and earth is mixed with it as it 

 is piled — usually in the proportion of about 5 cart-loads of earth 

 to 20 tons of manure. While the manure is in preparation, the rick 

 is turned at three or four different times until it is considered in 

 the proper condition. It is then put in the beds in the mushroom 

 house to the depth of about 8 inches and packed quite firm. The 

 temperature of the manure will rise to 100 degrees or more, but 



34—7—1904 



