296 



THE FRUIT GARDEN 



a semi-span vinery is practically similar to the lean-to already described. Probably 

 even greater care should be exercised in very thoroughly binding the roof so that 

 there should be no outw^ard thrust on the walls, which is the true principle of 

 roof construction. The roof ventilator on a semi-span roof should always be on 

 the south side ; on no account, unless where exceptional reasons exist, should 

 the ventilator be on the north side. In dealing with these two types of vinery 

 construction an assumed width is taken and an assumed slope, but it is by no 

 means to be inferred that the very best grapes cannot be grown in houses of a 

 different width and a different slope. There is no fixed rule : the wide house 

 will grow more, but it may not follow, better grapes. In short, a good gardener 

 will grow good grapes in a very poor house. Fig. 2 represents a section of a 



Fig. 2. — Semi-Span Vinery 

 (In Section) 



semi-span house, which, as will be seen, is practically the same in construction as 

 the lean-to. 



Span-Roof Vinery. — For market purposes and where very large quantities 

 of grapes are required, or where there are no high walls, the span-roofed 

 form should be adopted, and there must be a radical change in aspect. 

 In the case of the lean-to and semi-span the vinery should face the 

 south with as little east or west aspect as may be practicable, but the span- 

 roofed structure should run north and south as evenly as possible, so that 

 each side may get an equal portion of sunlight and heat. The span-roofed 

 vinery, being as it were two lean-to's, should be very much wider if a large crop 

 is expected. A good width would be 30 feet, equal to two lean-to's at 15 feet, 

 and giving a rafter with not too steep a pitch of about 19 feet. The sides in 

 this case also should be about 4 feet — i foot of wall above floor level and 3 feet 

 of glasswork framing. There should be ample means of ventilation, an opening 



