s 
INDOOR COMPOSTING FOR MUSHROOM CULTURE 5 
Manure takes on characteristics typical of each new composting 
environment to which it is subjected, and, therefore, the last few days 
of sweating out are usually the most important. 
It is only during the last 3 or 4 days of indoor composting that the 
air temperature surrounding the beds can be raised to 130° F. without 
danger of overheating the manure or excessive drying out. Usually 
the heat generated by the manure will not be sufficient at this time to 
bring the air temperature to 130°. Therefore the application of 
auxiliary heat during the last few days is highly desirable from the 
standpoint of final conditioning of the manure and insect eradication. 
When outdoor composting is reduced to 2 or 3 turnings at rapid 
intervals the process may be considered merely as a means of mixing 
and moistening the manure while carrying it through the initial ex- 
plosive fermentation to reduce the tendency to overheat and lose 
moisture during the subsequent prolonged sweating out. 
The extent to which it will be found advisable in commercial prac- 
tice to shorten outdoor composting and lengthen indoor composting 
will vary from one establishment to another, depending on the facili- 
ties available for mixing and breaking up the manure and for con- 
trolling temperature and moisture during sweating out. With proper 
facilities there appear to be good prospects of a saving in both labor 
and manure from shortening the outdoor composting. In the experi- 
ments at Arlington Farm indoor composting was found to require less 
labor than composting in outdoor heaps, and normal yields were 
obtained on beds using about half the usual amount of fresh manure 
per unit of bed space. 
U.S. GOVERNMENT PRINTING OFFICE: 1941 
For sale by the Superintendent of Documents, Washington, D.C. - - - - - - Price 5 cents 
