Chap. II.
ON THE STRUCTURES ADAPTED FOR THE GROWTH OF CUCUMBERS.
I will preface the following remarks on the structures adapted for the growth of Cucumbers, by stating, that a forcing house, a pit, and a common frame, present the means of bringing this fruit to its perfection, equally, one with the other, provided that a course of cultivation suitable to the structure, is followed out; the comparative merits of each, depend not so much on the nature of the results which may be obtained by adopting them, as on the facilities they afford for the attainment of those results.
The use of the common frame, and the ordinary hotbed of fermenting manure, nevertheless involves these difficulties:—the fermentation is liable to become excessive, and that in a very rapid manner, and also to decline as rapidly; the heat, when declining, cannot be speedily restored in unpropitious weather; it is materially checked in its action, by that particular state of the weather, which renders its efficient action most essential; it involves almost an infinitude of labour; and after all, it is uncertain in its action: when such difficulties as these, are overcome, Cucumbers can be grown to perfection, on dung beds, assisted by the common garden frame and sash.
The brick pit, when heated by fermenting manure, presents difficulties of the same nature with the preceeding, though in a less powerful degree: but when these structures are heated by means of hot water, in any of its various modes of application, there need be no irregularity, nor uncertainty in its action; because the supply of the elements of vegetable developement, and of the agents by whose aid they are applied, may, to a very great extent, go on uninterruptedly.
A forcing house, whilst it secures all the advantages which are presented by a pit, combines with these, some important points which are peculiarly its own: by adopting a pit, we provide a structure of which Cucumbers manifest their approval, by thriving equally as well as in their more ancient location on a dung bed; but further than this, a pit enables us to dispense with much of the labour, and all the filth, and the uncertainty which are consequent on the use of fermenting manure as a means of keeping up the temperature in which they are grown. In a small forcing house, besides these advantages being secured, all the operations of care and culture, can be performed just when they become necessary, without exposing the tender foliage of plants which have been submitted to an artificially elevated temperature, to the chilling influence of cold air, which is admitted whenever the sashes of an ordinary frame or of a pit, are opened, in order to bestow these necessary attentions. It may be urged that a dung bed has still the advantage, on the ground of economy; but when a fair calculation is made of labour and loss or anxiety on the one hand, and of duration on the other, such an assumption, will be quite untenable. Neatness, convenience, certainty, and economy, are the principal points of advantage which are gained by the adoption of pits heated by means of hot water, over those of a structure, depending for its supply of heat, on the aid of fermenting masses; whilst the attainment of a still greater degree both of convenience, and of certainty, which may be secured by cultivation in forcing houses, point out at once the advantages which render such houses, preferable to pits.
The application of the gutter system of heating, was not long since thought to be an improvement of great importance, and there can be no question but that it affords a means of regulating the moisture of the atmosphere of hothouses, in conjunction with the temperature, which prior to its introduction had not been attained; and as such, it is worthy of extensive adoption: it requires however some judgement in its adaptation to particular structures, and to render, it suitable, to effect any particular object for which it may be employed.
The tank system as a means of applying bottom heat, employed either in conjunction with the gutters, or with ordinary piping, to supply heat to the atmosphere, is the most important advance which has hitherto been made towards supplying the wants of those plants, which require such peculiar aid; and with reference to the Cucumber, it may be regarded as furnishing a new era in its cultivation.
The importance of bottom heat in the culture of tender plants, has always been well known by its practical effects. The mean temperature of the soil, at a slight distance below the surface, is universally above that of the superincumbent air; and consequently some degree of bottom heat is always supplied to plants, in a state of nature. Naturally, by means of subterraneous heat, and also by the absorption of the sun’s rays during the time they are forcibly directed towards the earth, it possesses the means whereby any material degree of cold at the roots of plants is prevented; and when the soil is acted on by the unveiled sun of an eastern sky, we cannot but feel certain, that even a considerable amount of heat must be experienced: hence arises the importance of taking advantage of every ray of sun which our climate affords, when the culture of the Cucumber, or of any native of warmer latitudes, is attempted out of doors in this country; and also of using every possibly available means of increasing rather than diminishing the temperature of the soil: and hence too, in forcing not only the Cucumber, but also every other plant which requires to be submitted to a confined atmosphere, and an elevated temperature, arises the necessity of providing such a degree of warmth at the root, as may tend to keep its vital powers in a vigorous state of action; it will effect this, by acting in conjunction with moisture, as a solvent of the food which is primarily contained in the soil in a solid form, but can only be taken up by the capillary action of the spongioles of the roots, when converted into a fluid state. The science of Chemistry has taught us that the ingredients composing the soil, act on, and dissolve, and combine with each other in various ways, sometimes being simply dissolved and held in solution, and at other times, entering into new combinations, and forming new compounds; but in all cases, the natural agents, heat and moisture, are necessary to produce these results, and to present to the tender roots of plants, food so duly prepared, as to be fit for their assimilation. Warmth in the soil, acts beneficially also, by preventing the sudden or undue interruption of the excitability of plants growing in it, which would be likely to result from the lowering of the temperature of the plants by evaporation, were it not for the action of the antagonist force, existing in and exercised by the heated soil, which heat, is communicated to, and absorbed by the plants.
It may be regarded as an established and universal rule, that all plants require the soil, and the atmosphere in which they are cultivated, to correspond with the natural circumstances under which they flourish; and as it has been repeatedly ascertained that the soil is naturally a degree or two above the temperature of the atmosphere, we have certain and unerring data for the application of bottom heat, and no more powerful evidence than this can be desired, to condemn at once the application of a very powerful degree of heat, at the roots of plants.