ON THE REGULATION OF THE TEMPERATURE.
If we figure to our minds, a plant which in its native habitat enjoys a climate far more genial, and a temperature far more elevated, than our own country affords, it must be obvious that some regulation, and increase of temperature, either positively, by the artificial application of heat, or negatively, by affording shelter and protection, will be required in order to ensure any degree of success in its cultivation. The Cucumber is a reputed native of the East, and we have therefore in this supposed fact, an indication of the nature of the climate, which it should be our object to provide for it; but still it must be borne in mind, that in conducting any system of artificial cultivation, it is not at all times desirable, or even safe, to supply a resemblance to any part of the natural circumstances affecting the growth of a particular plant, unless we have the means of supplying the greater part, or all the conditions which exist in a state of nature: this I shall again have occasion to refer to.
By another step we arrive at the conclusion that the standard of temperature, to which the Cucumber is submitted in its cultivation in this country, is a point, varying with the individual opinion of cultivators; as some may take a part of the natural conditions of growth as their rule; others, all these circumstances; and others, again, various combinations of them.
Referring back again to the provisions of nature, we can scarcely hesitate to conclude, that in clear sunny weather, the temperature to which the Cucumber is submitted, cannot within reasonable limits, be permitted to rise too high; whilst at other times, when the weather is dull, or cloudy, and always at night, a much lower degree of heat ought to be applied. In sunny weather, the natural agents which cause excitement and activity of the vital functions, are in full action; and consequently at such periods we may rationally indulge in the application of those exciting agents which are under our controul—always however bearing in mind, that we must not unduly apply one agent, when we either cannot, or neglect to apply the others also. On the other hand, in dull weather, and at night, the source of light being in the one case absent, in the other obscured, a comparative state of lethargy or repose is prevalent, and the natural functions of vitality are but feeble in their action, if not in some cases, absolutely in a quiescent state; with such a state of things existing, it is barely rational to apply stimulants, and to induce unnatural excitement. The application of exciting and stimulating agents at such periods, may be compared in its effects to the excitement of a frightful dream acting on the human frame; the vital functions—not the vitality itself—cease during sleep, and both the animal and the vegetable should be at rest; excitement acts on both by deranging the system, at least for a time, and since a succession of these derangements are known to produce injurious results, we may be certain, that each seperate instance must have an evil tendency.
In applying this practically, to the case before us, it may be recommended, that the temperature in which Cucumbers are grown during winter, should not fall much below 60° Fahrenheit, at night; and in the day time it should not rise above 70° in dull weather, by the aid of heat artificially applied; in clear weather, by the influence of that glorious source of light and heat, the sun, it may be safely allowed to rise to 80°, or a little higher, before air is admitted. A somewhat higher range may be permitted, as the days lengthen, and the influence of the sun becomes more powerful; thus at night, it should not rise over 65°, by day 75° to 80°, and by sun heat to 90°. Thus it will be seen, that I have recommended the regulation of the temperature of the internal atmosphere, by that which is external; and it is my firm conviction that inattention to this simple rule, is the source of much of the failure, which is experienced by some of those who attempt the growth of plants, at any other than that, which may be regarded as their natural season of growth. It appears to me, most unreasonable, to aim at attaining any particular point of the thermometer, merely because any particular season of the year may be present, or any particular stage of growth attained. Even if in the sunny climes, from whence the Cucumber has been transmitted to us, there exists such an equality of temperature and atmospheric serenity, as some cultivators attempt in the growth of these plants; it surely cannot be consistent in us to equalize and elevate the temperature of our artificial atmospheres, when we cannot supply them at the same time with the same intensity of light, or provide for them the same serene and unclouded sky. It should rather be our object to adapt the plant to the climate of our country, since we cannot change the climate to supply the natural circumstances, with which the plant is favoured; and acting on this principle, we should never aim at supplying the agents which would induce a premature and therefore debilitated developement, when the whistling wind, and the drifting snow, tell us that Nature, would have, at least the members of her vegetable kingdom, be at rest.
Since however, it is apparent that during the depth of the winter season, at least when wintry weather is present, the progress of plants in an artificially heated atmosphere, ought not to be rapid, or unduly forced; it by no means follows that no progression at all should be made: the elements of growth maybe supplied; but the application of them should be guided by moderation, being lessened at those particular periods when the weather is least propitious, and increased during those periods when it is most favourable. In the works of Nature we may ever learn a lesson of consistency, for they are perfect: they teach us that food is requisite to maintain the life of all those objects which are endowed with it; that that food must undergo a process both of digestion and assimilation, ere its purpose is fulfilled; and that each of these processes depend on the action of natural agents. In the vegetable kingdom, heat and fight as derived from a united source, are the agents appointed to bring about these results, and in order to ensure their proper action, they must both be present in a powerful degree: in artificial schemes of culture, we can command a supply of the one, but the other is not within our power; our consistency therefore depends on our applying so much of the one under our controul, as will secure the united action of it, with the existing degree of the other—consequently, when light is absent, or deficient, heat should also be diminished; and when light is present and abundant, heat may safely be increased.