CULTIVATION OF TENDER FRUIT TREES. 



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which he proposed to effect this had the additional recommend- 

 ation of costing- much less in the way of construction than ordi- 

 nary walls, which are far from answering the desired end. 



In Mr. Ker's experiments the top only was covered, and the 

 sides and ends were left open, except during the prevalence of 

 very cold winds, when a common net was hung in front of the 

 trellis, in order to prevent to a certain degree the strong current 

 of air passing between the glass and the blossoms. When I read 

 the description I was delighted with the novelty and excellence 

 of the idea ; but at the same time it seemed incomplete so long 

 as the sides and ends were open ; and as several improvements 

 have suggested themselves to me, I beg leave to forward a section 

 and description of them, in order that others, about to erect pro- 

 tective trellises, may, if they please, take advantage of my ex- 

 perience. 



The effect of the glass roof alone is chiefly useful In checking 

 the upward radiation of the heat ; but the slight difference of 

 temperature, which is obtained either by night or day, is the 

 means of creating a constant current of cold air between the 

 branches and the glass ; and in keen, frosty weather this is par- 

 ticularly severe and injurious. It is evident that something more 

 is necessary than a simple netting being hung in front ; and I 

 think it will be generally admitted, that after going to the 

 expense of fixing trellises, making glass sashes, preparing borders, 

 and purchasing trees, it is worth while to go one step further, 

 and make perfect trellised frames by closing up the apertures on 

 all sides. Without this provision to husband the heat derived 

 from the sun's rays, the trees are scarcely so well off during the 

 day as they would be without the protection ; for an increase of 

 temperature is prevented by the constant current, and, by the 

 glass acting as a shade, the crop is retarded rather than for- 

 warded. 



Another objection against the original design is in the roots of 

 the trees being outside the trellis, and exposed not only to the 

 rain which falls directly upon the soil, but also to that which 

 runs off the roof. This evil may of course be obviated by cover- 

 ing the border with tarpauling or some other material ; but it is 

 a much simpler arrangement to have the border made beneath 

 the trellis, as the roots will then be in a temperature exactly pro- 

 portioned to that in which the branches are growing, without the 

 use of fermenting litter or other covering material. 



I propose to close up the back and ends of the frame with cheap 

 ^-inch boarding, and to hang the board nearest the top upon 

 hinges, so as to form a ventilator ; in addition to which the sashes 

 can be pushed down in very hot weather, and to keep the trees 

 back after the wood is well ripened in autumn. In regard to the 



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