412 VEGETABLE FORCING 



cial growers buy the usual supplies of city stable manure, 

 which is often shipped in carlots. 



In many instances the manure is placed in large piles 

 out of doors, as shown in Fig. 151, and allowed to fer- 

 ment. There are advantages in keeping the manure 

 under cover where there will be no loss from leaching 

 and where it will not dry out rapidly, but the objections 

 to open air composting are not serious. 



Certain essential chemical changes occur during the 

 process of fermentation, which also materially alter the 

 physical properties of the manure. Fire-fanging should 

 be avoided as much as possible. To encourage the proper 

 kind of fermentation it is necessary to keep the pile 

 uniformly moist and fairly . compact. The supply of 

 moisture in the compost should be watched carefully 



Fig. 151. Composting manure for the growing of mushrooms. 



from day to day. Copious applications of water or suffi- 

 cient amounts to soak the manure are necessary when it 

 is placed in piles, and the latter should not be more than 

 4 or 5 feet deep. It is generally customary to turn or 

 fork over the piles from two to four times during the 

 process of fermentation, which lasts about four weeks. 

 This operation is essential in order to secure uniform 

 fermentation throughout the compost and to make the 

 manure shorter or finer in texture. Water should be 

 added whenever necessary while the manure is being 



