630 



FRUIT GARDEN. 



water accumulates in the system, and is never 

 decomposed or removed by perspiration in the 

 requisite degree. In short, plants growing fast 

 by night can neither ripen their wood nor form 

 their inner structure well ; and, therefore, they 

 are incapable of developing their natural beauty, 

 or of resisting those extremes of temperature 

 which are natural to them." — Gard. Chron. 



Excess of heat injurious to plants. — With inex- 

 perienced people having the means of heating 

 a glass-house in their power, much greater in- 

 jury is done by keeping up an unnecessary de- 

 gree of heat than the reverse. They think, if 

 they have plenty of heat, that all that is neces- 

 sary in forcing or plant-culture is in their hands. 

 A few years ago we had recommended to us, by 

 the pine-growers of the day, roasters, Calcutta 

 pits, and all sorts of places that could be heated 

 little short of a fiery furnace ; the consequence 

 was, burning of the roots, scorching the tops, 

 abundant armies of scale and white bug, and 

 ultimately the loss of the plants themselves. 

 To this extraordinary heat humidity bore no 

 proportion, and ventilation was abandoned to 

 prevent the escape of the heat. These matters 

 are better managed now. A necessary tempera- 

 ture, with a corresponding degree of humidity, 

 and a perpetual change of air by day and night 

 ventilation, is now the practice of our best 

 growers. The effects of too high a temperature 

 in our forcing-houses are thus sensibly described 

 by Dr Lindley : " When, in the case of a given 

 plant, the temperature is permanently main- 

 tained at a much higher degree than the species 

 requires, it is over-excited. If the atmosphere 

 is in a proportionate state of humidity, the tissue 

 grows faster than the vital forces of the plant are 

 capable of solidifying it, by the decomposition 

 of carbonic acid and by other means ; its excit- 

 ability is gradually expended, the whole of its 

 organisation becomes enfeebled, the vital func- 

 tions are deranged, and a state of general debi- 

 lity is brought on. Such plants are soft and 

 watery, with thin leaves, long joints, slender 

 stems, and no disposition to produce flowers. 

 A slight lowering of temperature affects them 

 more than a much greater lowering would have 

 done under other circumstances ; and a per- 

 manent abstraction of light readily destroys 

 them. Their inability to decompose carbonic 

 acid, and to assimilate their food in proportion 

 to their rate of growth, prevents their becoming 

 so green as is natural to them, and gives them a 

 pallid hue ; and if it is their property to secrete 

 other colouring matter, that, like all their other 

 colouring secretions, is greatly diminished. But 

 if, with a preternatural elevation of temperature, 

 there is a proportionate abstraction of moisture, 

 the loss of fluid by perspiration and evaporation 

 goes on faster than the roots can make it good 

 or the tissue transmit it; the secretions of the 

 spurs are elaborated faster than the parts to 

 receive them can be formed ; the old leaves 

 burn and dry up, and young leaves perish in 

 like manner as fast as they are formed. Such 

 being the result of preternatural high tempera- 

 tures, in dryness and in moisture, it is easy to 

 conceive that, although such extremes can- 

 not but be prejudicial, yet that they may be 



approached for particular purposes with advan- 

 tage. A high temperature and dryness will be 

 favourable to the formation of secretions of 

 whatever kind ; while a high temperature, with 

 moisture, will lead to the production of leaves 

 and branches only." — Theory of Horticulture, p. 

 83. A high and moist temperature in the case of 

 pine-culture will grow young plants rapidly; 

 with fruiting plants the consequence would be 

 the production of innumerable suckers and 

 crowns much larger than the fruit. A curious 

 circumstance in connection with this is recorded 

 by Mr Knight in the third volume of " The 

 Horticultural Transactions," who says that the 

 effects of an exceedingly high temperature 

 caused unisexual plants to produce male flowers 

 only, while a very low temperature produced a 

 contrary effect; and he further observes that he 

 had many years previously succeeded, by long- 

 continued very low temperature, in making 

 cucumber plants produce female flowers only. 



Season of rest. — The vine, like all other plants, 

 requires a season of rest, that season commenc- 

 ing at the fall of the leaf. Vines, therefore, 

 grown in pine-stoves at that period should be 

 withdrawn, and their wood exposed to the open 

 air on the outside of the house. This is deemed 

 immaterial by some, and there have been in- 

 stances where they have been left exposed to 

 such high temperatures for several successive 

 years; yet in the end these vines will show the 

 bad effects of such unnatural treatment, and 

 finally dwindle away and die. Perpetual ex- 

 citement is as fatal to them as uninterrupted 

 exertion would be to animals. Perpetual ex- 

 citement exists nowhere in nature, although 

 annuals might at first sight be stated as an 

 exception to the rule. Their period of existence 

 is short, scarcely exceeding the growing season 

 of a perennial or ligneous plant. When they 

 perfect their seed they cease to exist, and the 

 seed, the material by which they are to be re- 

 produced, rests in the soil till the returning 

 season of growth. When plants are in a dor- 

 mant state the majority of them lose their 

 foliage, and in consequence of the want of 

 leaves they are unable to make use of the nou- 

 rishment applied to their roots, and hence it is 

 wrong to stimulate them with nourishment or 

 warmth, at least to the extent of causing them 

 to grow when they ought to be at rest. In 

 vineries where the plants cannot be withdrawn, 

 the fullest amount of ventilation should be 

 given during day and night. Notwithstanding 

 the advantages the vine enjoys by being kept 

 during its natural winter in a low temperature, 

 care must be taken that they do not suffer from 

 severe frosts, for instances have occurred where 

 vines exposed on the exterior of a vinery have 

 been killed; but this only happens in the most 

 intense winters. 



The best modes for withdrawing the vines at 

 this season are exemplified, vol. i., fig. 425, as 

 practised by Mr Saunders, and fig. 428, as in use 

 in the Royal Gardens at Frogmore, by either of 

 which the stems can be very conveniently with- 

 drawn without the usual danger of twisting 

 them near the root. Our own practice, whether 

 in pine-stoves or regular vineries, is, as soon as 



