52 MUSHEOOM GEO WING AND SPAWN MAKING. 



MUSHROOM SPAWN MAKING. 



The mycelium of the cultivated mushroom has long been known 

 commercially as " spawn." From early times it has been recognized 

 that mushrooms may be grown from spawn, and it is (juite certain 

 that in all attempts to propagate mushrooms spawn has been used 

 for the purpose. 



In France, in England, and in other countries in which the mush- 

 room has long been groAvn it is recognized that it is not profitable 

 continually to take growing spawn from one bed to be preserved as 

 '' seedage " for the next crop. The common expression is that the 

 spawn " runs out "" in about three years. There seem to be few or 

 no definite experiments indicating the exact conditions under which 

 the spawn in two or three years loses the power of vigorous mush- 

 room production. Nevertheless, it is the almost unanimous opinion 

 of all extensive growers that there is a marked diminution in the 

 yield after several successiA^e propagations from the spawn in the 

 mushroom bed. This has seemed to be true in the writer's experi- 

 ments, although it must be said that accidents to experiments under- 

 taken have made it impossible to report at this time upon the nature 

 of this running out. That deterioration does result is apparently a 

 fact accepted by all scientific men who haA'e given attention to mush- 

 room growing. It is possible, however, that under cert«in conditions 

 the spawn might be repeatedly propagated without loss of proli firm- 

 ness. It is not necessary to enter here into a discussion of possibili- 

 ties or to attempt to explain why weakening might be evident under 

 ordinary conditions. 



A " chance " method. — For practical purposes it is necessary to 

 renew the spawn and to secure, if possible, spawn which has not pre- 

 viously weakened itself by the production of nnishrooms — known as 

 virgin spawn. Natural virgin spawn may be found wherever " in 

 nature " it has been possible for the spores to germinate and to pro- 

 duce a mycelium. Ordinarily such so-called " spontaneous " appear- 

 ances of spawn may be anticipated in compost heaps, rich garden 

 beds, pastures near the feeding places of animals, etc. 



Many attempts have been made by practical growers to develop 

 ^■pawn from spores, sowing the gill portions of mature mushrooms in 

 specially constructed beds; but the results, so far as the writer is 

 aware, have not been satisfactory. As a rule, therefore, growers 

 have been compelled to rely wholly upon a virgin spawn which has 

 been obtained by chance. It is said that in the vicinity of Paris 

 some persons make a business of searching for this virgin spawn, 

 which they sell to the growers at a high figure. It is claimed that 

 they become so adept in detecting the ditferences in the character of 

 growth, the quality of odors, etc., that they can distinguish not only 



