VENTILATION 23 



wires. The whole trellis should receive three coats of 

 good white-lead paint as soon as finished, or at least before 

 the vines and lateral growths are trained thereto. 



VENTILATION 



Upon the manner in which fresh air is admitted to 

 forcing and other glass-houses in which plants are culti- 

 vated depends in a great measure the success or otherwise 

 which may be achieved by the cultivator. It must be 

 borne in mind that fresh air should be admitted to the 

 individual glass-houses to prevent the temperature from 

 rising above the desired degree of heat, and not, as is 

 sometimes the case, to lower it; bearing in mind also that 

 a superabundance of fresh air being admitted at one time 

 will not make up for a deficiency of this essential element 

 to good health at another time. On the contrary, the 

 quantity of air given in the early part of the day should 

 be increased and decreased in accordance with the rise 

 and fall of the internal temperature until closing time in 

 the afternoon arrives. Plenty of moisture should be 

 distributed in the forcing-house, in order to promote 

 and maintain a clean, healthy, rapid growth in the vines, 

 the judicious circulation of fresh air during the heat of 

 the day tending to induce a short-jointed, consolidated 

 growth, instead of the long-jointed, sappy growth which 

 invariably results when vines are grown in a close 

 atmosphere surcharged with moisture. In the case of 

 late grapes, it is a good plan to open the top and front 

 ventilators at about eight P.M. sufficiently to admit of a 

 gentle circulation of fresh air among the foliage of the 

 vines during the night, as no plant will flourish in a stag- 

 nant atmosphere ; closing the ventilators at six o'clock in 

 the following morning prior to distributing water over 

 the surface of the vine border and pathway. Keep the. 



