69 



It would require considerable space to enter fully into the elucidation 

 of all the principles involved ; it will, therefore, be considered sufficient 

 for the present to briefly trace the course of practice deduced from 

 many years 7 extended observation and experience in the growth of the 

 foreign grape. 



As soon as spring growth commences attention is at once directed to 

 the night temperature, so that it will fall at least 20 below the 

 average heat in the house during the day. In dull, cloudy weather, 

 of course, this difference between day and night may not be so great, 

 and if the nights are frosty it will be necessary to close the house ; but 

 in the absence of actual external freezing the ventilators should not be 

 wholly closed, even during the night. When all danger from night 

 frosts is passed which will vary, according to locality, from the mid- 

 dle of May to the middle of June the ventilators may be left open day 

 and night. During dull, cold weather it may be necessary to partially 

 close the ventilation both day and night ; but, as a general rule, the 

 same amount is used day and night. We have seen graperies where 

 the ventilators were never disturbed from the period of blossoming 

 until the ripening of the fruit. No constant anxiety is, therefore, felt 

 about shutting or opening sashes, and the liability to create sudden 

 changes of temperature, that frequent alterations of the ventilators are 

 sure to produce, are prevented. The temperature of the house will, 

 therefore, participate in the general changes of external atmosphere, 

 and though warm during sunlight, will be cool during darkness. Dur- 

 ing the warmest part of the summer the day temperature may vary 

 from 90 to 100 by day to 65 to 80 during the night. This lower- 

 ing of temperature during darkness insures a hardihood of growth 

 that enables the plants to endure any unfavorable change that may 

 occur, without sustaining the least injury. 



As air is heated its capacity for abstracting and containing moisture 

 increases, and unless the moisture is supplied from other sources it will 

 be drawn from the plants. To supply this evaporation, the soil in the 

 house should be kept damp on the surface. Once a day at least m 

 bright weather the soil will require to be sprinkled. It is a good rule 

 never to allow the surface soil to be entirely dry until the fruit is color- 

 ing to ripen ; but it is important to know that, unless in connection 

 with constantly night ventilation, this treatment may prove injurious. 



So far as the management of the atmosphere is concerned, this is all 

 the care required, and a crop of grapes is thus as easily grown as a 

 crop of potatoes, only with more certainty, because more under our 

 control. 



With regard to soil, pruning, etc., we will at present only remark, 

 that soil capable of growing good cabbages will grow good grapes, and 

 the strongest yearly growths give the best fruit. 



