68 



we find that in the climate of Britain, where the dull, sunless days are 

 more abundant, and the summer heat of less intensity and of shorter 

 duration than with us, the Hamburg and other exotic grapes ripen 

 yearly trained on outside walls and trellises, and this in a climate where 

 the heat is not sufficient to mature Indian corn, tomatoes, or even 

 peaches in common field culture, as with us. Neither can it be sup- 

 posed that our own summers are too hot or our winters too cold, as it 

 is well known that there is scarcely any plant that will not withstand 

 extremes of summer heat and winter cokl so well as the grape pro- 

 vided it maintains good health. But, unfortunately, there are climatic 

 conditions here during which the grape is rendered subject to the 

 attack of fungoids, by which its growth is checked, the wood prevented 

 from maturing, and a general debility engendered which enfeebles the 

 plant to a degree that sooner or later ends in its total destruction. 



This tendency to mildew is, then, the only obstacle in the way of 

 successful open-air culture in this section of the best wine and table 

 grapes of Europe, and is the only reason why glass structures have to 

 be employed in their culture, where an artificial temperature, more in 

 accordance with their requirements, may be maintained. The tendency 

 to mildew in the foreign grape having been found so great a barrier to 

 its extended culture in the open air, recourse was had to glass houses, 

 where protection could be afforded and means adopted for the exclu- 

 sion of this malady ; but in many cases even here success has not been 

 equal to expectations. The mistaken eagerness of many to keep the 

 plants in an artificial instead of a natural condition has led to frequent 

 failures. It appears very obvious that a plant which occasionally suc- 

 ceeds in the absence of any particular protection would be enabled to 

 do so uniformly by a very slight additional care, provided that this 

 additional care was bestowed in the proper direction ; and that such is 

 the case has been proved beyond a doubt. 



Having on another page of this report treated more particularly on 

 mildew and its origin, it may suffice to remark here, that it is altogether 

 dependent upon the amount of atmospheric moisture and proper venti- 

 lation; and without proper attention to these points, mildew is just as 

 likely to destroy the plants under glass as it would be those in the open 

 air. Keeping in view that these remarks are intended to refer to the 

 general routine management of what is now more definitely known by 

 the term cold grapery, we will briefly allude to what is considered the 

 main points of treatment. 



The principal points, then, are a low night temperature, exclusive top 

 ventilation, and the constant presence of moisture available for evapo- 

 ration. The baneful effects of a high temperature in plant houses has 

 V>eeu shown in previous reports. It has been proved repeatedly that 

 Jow or bottom ventilation in a grapery is conducive tQ mildew, and 

 aridity must be prevented by the presence of moisture. 



