40 FRUITS AND VEGETABLES UNDER GLASS 



the one who loves his calling. Careless airing causes no end of trouble. 1 

 think that red spider is more often the result of careless airing than of dryness 

 of the atmosphere, though both cause the spread of this destructive insect. 



There are many details to be remembered under this head of airing, all of 

 which must be attended to in order to grow and finish up a house of Grapes 

 successfully. During the early forcing, the night temperature is regulated by 

 artificial heat. Then the day temperature will be from io° to 15° higher, ac- 

 cording to the state of the weather. In clear weather the day temperature 

 will naturally reach the higher mark. Still, it is not advisable to wait in the 

 morning until the thermometer registers the day temperature, but put a crack 

 of air on when the temperature has risen about five degrees, gradually increasing 

 as the temperature goes up. There is one principle which must be borne in 

 mind when airing, namely, never admit air to the extent of dropping the tem- 

 perature suddenly. The air should gradually be put on and also be gradually 

 reduced so as to have always a fairly steady temperatuic. As long as there is 

 fire heat in the house we can close down so that the temperature will rise a few- 

 degrees, but after the artificial heat is suspended, which will probably be in 

 the early part of June, leave a crack of air on, for if a house is closed tight, 

 with no fire heat on, the condensation is too great, and this may give rise to mil- 

 dew. Mildew IS very destructive in a grapery, especially at that stage when 

 the berries are small; the fungus seems to attack the bunches more readily than 

 the foliage, and serious trouble will result when they have become infested. 

 As the berries start to swell they are liable to crack, and as all the split berries 

 must he cut out, considerable loss might result. With fire heat it is a good plan 

 to close the grapery cari\- in tiie afternoon, allowing the temperature to e\en go 

 up to 85°. When the artificial heat is cut ofi', howe\er, then mildew will spread 

 very rap'dly in a tightly closed grapery; but if you always leave on an inch or 

 so of air, after the fires are dispensed with, that fungus can more easily be kept 

 down. There must be plenty of moisture during the day. Vines like a moist, 

 humid atmosphere. 



From the time a grapery is started until the shoots are an inch long, the\ 

 may be sprayed to good advantage three or lour times a day, then twice a day 

 until the Grapes begin to bloom. After this period it is not necessary to spray 

 any more. If the vines are sprayed between the time of thinning up and color- 

 ing, the berries may get disfigured with the water lodging on them. The same 

 moisture and atmospheric conditions can be maintained by dampening down the 

 border, the walks, and the ends of the houses or any free space that can be 

 sprinkled, but keep the water off the berries if you want perfect finish. Any 

 one in the habit of'-'spraying up to the coloring period may think that the red 

 spicier would now ha^^e a chance to get in its deadl\ work, hut this need nut 

 be if you keep an even, moist temperature. It it the sudden changes in the 

 temperature, whether it be high or low, which encourage the spread of insect 

 life. But should the red spider make its appearance, it must be checked 

 at once and there is nothing better for this purpose than a light dusting with 

 powdered sulphur. Red spider does not thri\e under this simple treatment, 

 and it should be applied as soon as the pest is detected. 



