CHAPTER II. 



GARDEN WALLS. 



§ 1. — ASPECT OF WALLS. 



The existence of fruit-tree walls, like 

 that of hothouses, may be traced to a 

 very early period. Generally speaking, 

 however, the majority of even the best 

 gardens in former times were fenced and 

 sheltered by hedges, which, so far as 

 shelter and fencing are concerned, were 

 found sufficient, though they were in- 

 adequate to the exclusion of hares and 

 rabbits. 



The chief use of walls is for accele- 

 rating and securing the ripening of the 

 best kinds of fruits, such as the peach, 

 apricot, and vine, which without their 

 aid could not be ripened in our climate. 

 According to the calculations of Mr 

 Gorrie, "the influence which walls have 

 in increasing the temperature of the air 

 immediately in contact with them, is 

 estimated at 7° of south latitude. The 

 mean temperature of a south wall, or 

 within a few inches of one, is equal to 

 the mean temperature of the open plain 

 of 7° farther south. Hence it is that 

 grapes which ripen in the open air at 

 Bordeaux require a south wall in the 

 neighbourhood of London, which is 7° 

 farther north." 



All authors agree in regard to the 

 utility of walls for ripening the best 

 kinds of fruits ; but considerable differ- 

 ence of opinion exists as to the aspect 

 they should present to the sun. Switzer 

 in his " Practical Fruit Gardener," 

 (p. 312,) says that south walls have been 

 considered the best for ripening fruits, 

 but that later experience and observation 

 have not confirmed that opinion. For, he 

 says, " when the days are loDg and the 

 heat of the sun in its greatest strength, 



VOL. I. 



it is too late before the sun shines on 

 them, and it leaves them early in the 

 afternoon. Besides, when it is mid-day, 

 the sun is so much elevated above the 

 horizon, that it shines but faintly and 

 very sloping upon them, which makes 

 the heat to be much the less, inasmuch 

 as a smaller quantity of rays fall upon 

 such a wall — it being visible that, both 

 before and after noon, the sun shines 

 hotter than when it is in its highest 

 meridian — whence it is natural to infer, 

 that walls with a little inclination, either 

 to the east or west, are the best aspects ; 

 and of the two, the east and south- 

 east are to be preferred to the west or 

 south-west, though they are as much 

 exposed to the sun as east walls are. In 

 my opinion," he continues, "a south 

 wall, inclining about 20° to the east, is 

 preferable to any other, inasmuch as the 

 sun shines as early on it as on a full east 

 wall, and never departs from it till about 

 two o'clock in the afternoon." 



With a view to obtain a comparatively 

 equal degree of solar heat, Hitt recom- 

 mends having no direct south wall at all, 

 and arranges his garden as shown in fig. 

 4. In respect to aspect he says, in " Trea- 

 tise on Fruit Trees," (p. 33,) " The sun's 

 rays continue no longer upon the south- 

 west wall than three in the afternoon, 

 which is best for all our tender fruits ; 

 for as apricots, peaches, and nectarines 

 blossom early in the spring, at which 

 time our climate is frequently attended 

 with frosty nights, destructive to both 

 blossom and fruit, the sun's rays, darting 

 in lines at right angles upon the wall at 

 nine o'clock, dissolve the congealed mois- 

 ture much sooner than if they darted 

 upon it at right angles at noon, which 



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