CHAPTER V 

 SOIL PREPARATION 



Ideal conditions in the greenhouse must be created, for 

 no soil in its natural state possesses all of the requisites 

 for the successful production of forcing crops. The 

 vegetable forcer should be able to grasp the particular 

 problems relating to the preparation of the soil to be 

 used. Hard and fast rules cannot be laid down, because 

 conditions are extremely variable. Different soils 

 demand different treatment. But whatever the soil, it 

 must have the required physical properties and contain 

 an abundance of available plant food. It must also be as 

 free as possible from harmful insects and plant diseases. 

 The greatest care should be exercised in the preparation 

 of soils for forcing purposes. 



Changing soils. In the early stages of the greenhouse 

 business gardeners and writers on vegetable forcing 

 considered it necessary to change the greenhouse soil 

 every year or two. Renewal was regarded necessary in 

 order to provide a soil which possessed the correct 

 physical and chemical properties. It was found, too, that 

 insect pests and plant diseases became troublesome 

 unless the soil was changed quite frequently. The 

 custom is a good one for small greenhouses and private 

 places where it is not practicable to employ modern 

 methods of soil preparation. There are hundreds of 

 private and small commercial houses where steam is not 

 available for sterilizing the soil. Under such circum- 

 stances it may be best to renew the soil quite frequently. 

 On the other hand, it is highly probable that summer 

 mulching with manure and sterilizing with formalin 

 would be just as satisfactory in most instances as chang- 



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