244 GREENHOUSE MANAGEMENT. 



bright days in the spring, air may be given for three 01 

 four hours during the middle of the day, but it is well to 

 close up early, in order that the heat from the sun maj 

 be trapped, and used to warm up the houses for the night. 



FORCING G HA PES. 



This term is now used in reference to several oper- 

 ations. In a strict sense, it applies to the starting of 

 the vines by the aid of artificial heat, at any time from 

 December to February or March, with the object of 

 securing fruit in advance of the main crop. Forcing is 

 also necessary with varieties that will not ripen without 

 artificial heat, which may be used, to start them earlier 

 than would otherwise be possible, or it may be used to 

 ripen them in the fall, or both. Another use of the hot 

 vinery is to grow varieties that require a rather higher 

 temperature than is afforded by our climate. 



If vines are to be used for early forcing, they must 

 be brought into this habit gradually, and by starting 

 them one year by the first of March it will be possible 

 to start them a fevV weeks earlier the next year, and by 

 continuing this, the time at which they can be started 

 will be carried back to January, or even December. It 

 will take about five months for the early varieties to be 

 brought to maturity in the forcing house. 



Firing may begin about the first of March in the 

 hot vinery, for the main crop, and should be regulated 

 to give about the same temperature as in the forcing 

 grapery proper. At the time the fruit sets, and as it 

 ripens, rather more heat will be required, in order that 

 ventilation may be given. If the season is cold and wet, 

 the fire heat will do much to hasten the growth. 



KEEPING THE FRUIT. 



"When thoroughly ripened, the fruit of some vari- 

 eties will hang on the vines for a long time. By main- 

 taining a temperature of about 45 degrees, and securing 

 a dry atmosphere by thorough ventilation, some of the 



