336 Glass 



two general types of forcing: the plants may be started 

 Tinder glass, and then transplanted into the open ; they may 

 be grown to maturity under glass. 



1. QUANTITY OF GLASS REQUIRED 

 How much glass the vegetable-gardener needs depends 

 (1) on how intensified are his operations, (3) in what sea- 

 son he wants the major part of his crops, (3) the region, 

 (4) the kinds of crops. These, factors are largely deter- 

 mined, in their turn, by the man's location with reference 

 to market, and the price of labor and land. Very small 

 areas sometimes have sufficient glass to cover them. 



Glasshouses are increasing in number and popularity.. 

 They are driving out hotbeds for the forcing of winter 

 stuff. But for general vegetable-gardening, the coldframe 

 and hotbed remain, although their relative importance is 

 likely to diminish. These humble structures are desirable 

 because they are cheap, because they allow the person 

 quickly to change or modify his business (a great advan- 

 tage on rented land), and because they can be removed 

 when the spring forcing is accomplished, allowing the land 

 to be used for other purposes. The growing of winter 

 vegetables in the North (under glass) is a special busi- 

 ness, and is not discussed in this book. 



Vegetable-gardening glass is usually computed in sashes. 

 A normal sash is 3 x 6 feet in surface area. Sashes are 

 combined into frames. A frame is a box covered by four 

 sash, — that is, an area 6 x 12 feet. For general and mixed 

 vegetable-gardening, about twenty-five sash are sufficient 

 for an acre of garden, consideriilg that the plants are to 

 be transplanted to the field, not matured under the sash. 



