Book IV. OPERATIONS OF EXOTIC CULTURE. 423 



Sect. VI. Operations to imitate warm Climates. 



2201. The imitation qfivarm climates by hot-houses must not be confounded with the art 

 of forcing the vegetables of temperate climates into the premature production of their 

 flowers or fruit. The former was the first object for which hot-houses were erected, and 

 conservatories, green-houses, and plant-stoves existed in this country before any descrip- 

 tion of forcing-house ; even pineries are of subsequent introduction to botanic and orna- 

 mental hot-houses. The various climates and constitutions of plants require atmospheres 

 of different degrees of temperature and moisture : but experience has proved, that 

 the plants of every warm country in the world may be grown in one or other of the three 

 following descriptions of hot-houses : 1. The green-house, of which the varieties are the 

 Sinarium, or house for Chinese plants ; the Conservatory, in which the plants are inserted 

 in the soil without pots ; the Cold-frame for bulbs, and Heathery for Cape plants, &c. 

 2. The dry-stove, for succulent plants, or such as require a dry atmosphere ; and 3. The 

 moist or bark-stove, for pines, palms, and the tropical plants which require the highest 

 degree of heat, and an atmosphere moist in proportion. 



2202. Treatment common to the three species of artificial climates. \ In general, hot-house 

 exotics are kept in pots ; but in some cases, fruit-bearing plants, as the orange, and plants 

 with large roots, as the Strelitzia, and luxuriant creepers, as the different Passifloras, are 

 planted in the ground. The soils are, of course, very various, and can only be treated of 

 with advantage under each species, tribe, or family. There are none of them, however, 

 that will not thrive either in bog-earth, sand, or loam, or a mixture of these. For pines, 

 oranges, and large-blossomed plants, rotten leaves or old cow-dung are added with advan- 

 tage, and to some of these, as to the orange and pine-apple, liquid manures are frequently 

 applied. Gardeners in general are averse to the application of any thing rich to the soil 

 of exotic plants which are not cultivated for their fruit, a prejudice evidently contrary to 

 analogy, and originating, in all probability in the circumstance, that it is in general de- 

 sirable to keep exotic plants small, both for want of room in ordinary-sized houses, and by 

 that means to induce a flowering state. Now, however, when the facilities of hot-house 

 building by wrought and cast iron admit of covering several acres of ground with a glass 

 roof at fifty, a hundred feet, or at any distance from the surface ; and when the mode of 

 heating by steam readily admits of keeping such a space at any required temperature, all 

 exotic plants, where expense is not an object, may be planted in the ground duly pre- 

 pared, cultivated and manured like a shrubbery, and allowed to attain their natural size. 

 Such a house or scene may be watered after Loddiges' method already described (1689.), 

 and its temperature regulated, if desired, by the ingenious machine of Kewley. {fig. 217.) 

 With the exception of temperature, the operations in imitation of artificial climates are 

 the same as those for forcing ; we shall, therefore, confine ourselves to indicating the 

 temperature of its three leading departments. 



2203. The green-house is freely exposed to the influence of our atmosphere when the 

 open air is not colder than 48 of Fahrenheit, and when winds and rains do not prevent the 

 opening of the roofs or other means of ventilation. " As long as the weather continues 

 fair without frost," says Abercrombie, " open the green-house windows in the daytime an 

 hour after sunrise, and close at the same time before sunset. Never admit air by the 

 door or sashes in foggy or damp weather, or when bleak cutting winds prevail. The admis- 

 sion of air in the middle of a clear frosty day will not hurt the plants, if counteracted 

 by fire heat. Admit air freely when the external temperature is at 42 by Fahrenheit, 

 or above ; admit it guardedly when between 35 and 42 ; but not at all when under 35 

 before the furnace is employed." Green-house plants are generally placed in the open air 

 during the five mildest months in the year, either by taking off the roofs of the houses 

 when these are moveable, or by removing the pots, and placing them in the open garden. 



2204. Dry-stoves are opened night or day in the summer seasons, but only during sun- 

 shine in winter and spring, beginning as in the forcing-houses, by opening the top sashes or 

 ventilators first, by which the external air descends and cools down the temperature, 

 partly by mixing with the internal air, and partly by forcing it out. Afterwards, when 

 the temperature of the atmosphere is above 50, the lower or front sashes or ventilators 

 may be opened, by which means a regular circulation or breeze is promoted in every part 

 of the house, if a detached house ; and in most parts of it, if forming part of a range of 

 connected houses. 



2205. Moist or bark stove. The range of temperature which bark-stove plants can endure, 

 " is from 63 to 81 of Fahrenheit, the instrument being in the middle of the house, at a 

 considerable distance from the furnace, and out of reach of the sun's rays." According to 

 Abercrombie the temperature by artificial heat of the hark-stove " is 58min. 70 max. 

 When meridian summer is felt, the temperature must keep pace with the increase of heat 

 in the atmosphere ; and therefore will ascend through all the intermediate degrees, to 75, 

 80, 85, 90, 95, and even 100. The maximum heat in the house, in July and August, 

 mav in general be kept down to 90, by free admissions of air, and by evaporation from 



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