194 



THE FARMERS' REGISTER. 



ihe means of insuring a proper temperature to 

 the soil in which he !J;rows hie planis, and that 

 this is requisite (or hardy as well as tender species ; 

 and 1 entertain liitle doubt that the time is at 

 hand when it will be considered quite as neces- 

 sary to furnish heat for the soil as I'ur the air; not, 

 however, heat without moisture, lor that would 

 evidently produce much o;reaier evils than it was 

 intended to cure, as has indeed been found by 

 inconsiderate ex[ierimenters. 1 quite agree with 

 Mr. VVritiren in believing tiiat it is the tempera- 

 lure and moisture of a s ;il, much more than its 

 mineraloiiical quality, thai determine iis influence 

 upon vegeiaiion. (See Erster Jahresbericht, 4'C-, 

 am Mitid und Nieder-Jiliein, p. 64.) 



Mr. Fintelaiann, the king of Prussia's gardener 

 at Potsdam, is celebrated fur his success in the 

 difficult an of forcing cherries, and he has given 

 an account of his practice, (Gard. 3Jag., vol. 

 iii., p. 64,) in wljich it appears that the most pecu- 

 liar leature is the strict attention he pays to the 

 temperature of the roots. He first soaks the roots 

 in water heated by the mixture of equal parts of 

 boiling and cold water; he afterwards sprinkles 

 the trees with lukewarm water, and he continues 

 to employ it of the same temperature as long as 

 watering is required. 



It seems indeed clear, that the success ol' the 

 Dutch in obtaining an abundance of fresh vege- 

 tables, such as lettuces, during the whole winter, 

 is in part owing to their being able to maintain 

 a gentle bottom heat. No doubt this is connected 

 with the abundant light which their forcing 

 etructures admit, and with other causes of con- 

 siderable importance; but none of those causes 

 can be supposed likely, in the absence of the 

 bottom heat, to produce such a result as the Dutch 

 gardener.-: obtain. 



If it is necessary that the temperature of the 

 soil in which plants grow should be cnrefully re- 

 ' gulated, and adjusted to their natural habits, it i-^ 

 no less requisite that the water in which aquatics 

 are cultivated should be also brought to a fitting 

 heat. Mr. William Kent succeeded well in mak- 

 ing many tropical species flower, by growing 

 them in lead cisterns plunged in a tan- bed, (H<>rt. 

 Trans., iii. 34,) in a clwse heat. In like manner, 

 Mr. Christie Dufi' procured flowers in abundance 

 from Nymphcea rubra, cmrulea and odoraia by 

 ■placina ihem in a cistern in a pine stove upon the 

 end flues, where the fire enters and escapes; or 

 by plunging them into tan-beds in pine houses, 

 varying in temperature from 80° to lOO-'. (liort. 

 Trans., \-\i.2S6.) Very lately, Mr. Sylvester, of 

 Chorley, in Lancashire, obtained fine flowers from 

 Nelumbium luteum, by paying attention lo the 

 temperature of the water. When he kept the 

 Jailer at 85°, the plants grew vigorously, and 

 were in perfect health, but flowerless; but by 

 lowering it to 70^-750, which more nearly ap- 

 proaches the heat to which the plant is naturally 

 accustomed, the magnificent blossoms were pro- 

 duced and succeeded by seeds ; the red Nelum- 

 bium, however, which inhabits countries with a 

 greater summer heat than the yellow, at the same 

 lime suHered by this lowering of temperature, 

 none of its blossom buds having been able to 

 unfold. (Bot. Mag., xiii. n. s. t. 3753.) The 

 water of rice fields, in which the red Nelumbium 

 flourishes, was seen by Meyen al 113°, at Lantao, 

 in China. 



An opinion has, nevertheless, been entertaiupd, 

 that botiom heat is useless : there is in the Horti- 

 cuhural Transactions (vol. iii. 288.) a paper to 

 show that it is injurious ; and the authority of 

 Mr. Knight has been relerred to in support of 

 the opinion, in consequence of that great horii- 

 culturist havinc expressed a belief that the " bark- 

 hod is worse than useless." {Hort. Trans., iv. 

 73.) But Mr. Knight repeatedly disavowed en- 

 tertaining any such seniiments. In one place, 

 he slated that the temperature of the air of the 

 stoves in whiih his pine-apple and other stove 

 plants nrrevv, without bark or other hot bed, u-^ually 

 varied from 70° to 85'^ ; and ihat the mould in 

 his pots, being surrounded by such air, acquired 

 and retained, as it necessarily must, very near 

 the same asgregate temperature, but subject to 

 less extensive variation {Gard. Mag., v. 365); 

 in another, he says the temperature of the air was 

 varied in his stove generally from about 70° to 

 85^^ of Fahrenheit ; and he ascertained, by keep- 

 ins a thermometer immersed in the mould of the 

 pots, that the tt^mperature of the sod varied very 

 considerably less ilian that of the air of the stove ; 

 the mould being in the morning generally some 

 degrees warmer than the air of the house, and 

 ill the middle ol the day, and earlv part of the 

 evenins, some degrees cooler, (^Hort. Trans., 

 vii. 255.) 



It is, therefore, clear that he considered a high 

 temperature necessary (or the roots of his pine- 

 apple plants ; and we find, from one of his pa- 

 pers, (Hort. Trans., iv. 544,) that he considered 

 it better lo obtain the requisite temperature froai 

 the atmosphere than from a bark bed, the usual 

 source of botiom heat, " because its temperature 

 is constantly subject lo excess and deliect ;" and 

 heeven admitted that if llie bark-bed could be 

 made to give a steady temperature of about 10° 

 below ihat of the day temperaiure of the air in 

 the stove, pine plants would thrive better in a 

 compost of that temperature than in a colder. 



It is, therefore, plain that the dispute about 

 bottom heat was not as to the necessity of it, but 

 as to the manner of obtaining it, which, as it 

 concerns the art of gardening,. I need not further 

 notice. 



We liave, doubtless, much lo learn as to the 

 proper manner of applying bottom heat to plants, 

 and as to the amount they will bear under parti- 

 cular circumstances. It is, in particular, probable 

 thai in hot-houses plants will not bear ihe same 

 quantity of bottom heat as they receive in nature, 

 because we cannot give them the same amount 

 of light and atmospheric warmth ; and it is ne- 

 cessary that we should ascertain experimentally 

 whether it is not a certain proportion between the 

 heat of the air and earth, that we must secure, 

 rather than any absolute amount of botiom heat. 



It may also be, indeed it no doubt is, requisite 

 to apply a very high degree of heat to some kinds 

 of plants al particular seasons, although a very 

 much lower amount is suitable afterwards ; a 

 remark that is chiefly applicable to the natives 

 of what are called extreme climates, that is to 

 say, where a very high summer temperature is 

 Ibllowed by a very low winter temperature. Such 

 countries are Persia, and many parts of the Uni- 

 ted States, where the summers are excessively 

 hot, and the winter's cold intense. The seeming 

 impossibility of imitating such conditions arti- 



