We hope that those of our friends who have made any observations, or have anything to say on this interesting subject will be kind enough to communicate them to us.—Ed.
AMMONIA ON PLANTS.
The subject of the action of Ammonia on plants is exciting considerable attention in England. We copy below from the Gardener’s Chronicle accounts of experiments, the first of which is being tried at the Horticultural Society’s Garden.
M. Ville’s mode of giving Ammonia to plants, with a view to increase their bulk and vigour, is being tried in the large stove in which one of his apparatuses has been placed. It consists of two clear glass bottles with long necks, furnished with tight-fitting corks, in each of which is inserted a small bent glass tube. These two tubes are joined together by means of an India-rubber connection, or small hose, thus forming a communication between the two bottles. In the cork of one of the bottles is an escape tube (also of glass), which is connected (by means of a small India-rubber hose), with other small glass pipes that are laid all along and across the bed, and through which the ammonia is intended to pass, in order that it may be the better diffused among the plants. When the bottles are put to work, one is charged with chalk, on which is poured sulphuric acid, and the other with unslacked lime, over which is poured a solution of ammonia. The result of this experiment will, of course, be published in due time. Its conduct has been entrusted to Mr. Spriggs, the young man in charge of the house, who is to note down its effects daily, and report the same to the Vice-Secretary. In another column will be found some further account of furnishing plants with more ammonia than they can get under ordinary circumstances.
By Mr. Deane, Vice President of the Pharmaceutical Society. Effects analogous to those produced by M. Ville (see last year’s volume, p. 755), with ammoniated air on the leaves of growing plants, have been observed by me, as the results of applying solutions of ammoniacal salts to the roots. My attention was first effectively turned to the subject about eight or ten years since, when an extensive grower of Pelargoniums, Fuchsias, and Roses, applied to me for some remedy for the sickly condition of his stock; which, if left unchecked, would insure a very severe loss to him. On examining the plants they were found to be in a starving condition, the roots having filled the pots and exhausted the soil; consequently, the leaves had lost their healthy green colour, and become very pale, with a strong tinge of yellow; the lower leaves were quite yellow, spotted, and falling off. The natural remedy was obviously fresh potting, but as the plants were already in pots best adapted to answer the purposes of the grower, some other remedy had to be devised. I therefore made a very weak solution of sulphate and carbonate of ammonia, and therewith watered the roots of the plants once a day, in the evening; and to insure any observed results as to the effect of the ammonia, certain rows of the plants on the stage of the greenhouse were selected for the experiment. In a few days the effects of the ammonia were most marked and satisfactory. The leaves began to put on a very remarkable appearance, the course of the veins, or spiral vessels, becoming perfectly green, the colour commencing at the basal portion of the midrib, and thence spreading through all the reticulations, until the tissues were perfectly restored to their normal and healthy condition; and, in fact, the plants thus treated looked more vigorous than they had ever done before, being much darker colour and firmer in texture. The contrast between these plants and those which had received no ammonia left no doubt about the efficiency of the application. I forget the effects upon the flowering of the Pelargoniums, but there was certainly no deficiency of flowers on the Fuchsias and Roses; they were, moreover, finer and better coloured than usual. On a subsequent occasion a gentleman’s gardener applied to me in a similar dilemma; he had a house full of fancy Pelargoniums preparing for a flower-show, at which he expected to take the first prize. Just as the trusses of flower buds were emerging, and there was every prospect of a good bloom, the lower leaves of the plants began to turn yellow and spotted, and then to fall off, leaving the plants bare, where the foliage was considered an essential point of beauty. I examined the roots and found them nearly filling the pots, it was therefore evident there was not sufficient nutriment left in the pots to meet the extra demand made by the large number of flower-buds; the latter were, consequently, deriving their nourishment from the leaves—the natural storehouse of the food of plants during the growing season—and of course exhausted the lower leaves first. They were treated precisely as in the former instance, and with the same results; the lower leaves became healthy, and the flower-buds progressed favourably to maturity, being of good form and colour. The success of these experiments became known to other gardeners in the neighbourhood, some of whom were equally successful, while others did not derive that satisfaction from the use of the ammoniacal solution, either from not understanding the principle of its application, or from a desire to accomplish more than they were capable of, when it frequently happened the plants became too vigorous to flower well. There is no doubt but that M. Ville is correct in stating that the flowering is arrested if the application of ammonia is made at a certain period of the development of the flower-buds. Few plants if grown too vigorously will flower well, if at all. A certain check in their growth is absolutely necessary, and the summer’s sun or winter’s cold, under ordinary circumstances, effects this perfectly in this climate—the former by perfecting and condensing the elaborated sap, and the latter by arresting vegetation altogether. Too much moisture and shade cause those parts intended for flower-buds to be developed as leaves. In the Aloe tribe when the flower stem is thrown up, it is at the expense of the outer leaves, the elaborated juices of which it appropriates, the roots at this time not being in action, because it is towards the close of a long period of dryness. If when the flower-stem is beginning to rise, the roots are watered, all further development of the stem is arrested, the leaves only being developed. The same thing takes place with many bulbs whose period of flowering is not the same as that for leafing. Many Cape bulbs follow this law; for example, the Hæmanthus, the flowering of which is at the expense of some one or more of the outer coats. If these plants are watered at the wrong period, or if they have had not that proper rest which Nature designed they should have under the influence of a roasting sun, such as their native country affords, no flowers will be produced, but in their stead a vigorous development of leaves. It would appear, therefore, that the arrest of development of the flowers and fruits of the plants treated with ammonia, is not so much the result of any specific property possessed by this substance, as by its bringing about artificially those conditions which may occur naturally, or be produced by other means. Also, that the application of ammonia to plants may be attended by results varying according to the conditions under which it is applied, and the object it is desired to obtain. The following is the formula for the solution alluded to in the previous note by Mr. Deane:—Sulphate of ammonia, 7000 grains; sesquicarbonate ditto, 1000 grains; water, 80 fl. oz. Dissolve. Of this solution one fluid once to a gallon of water will make a solution, sufficiently strong for all ordinary purposes.—Pharmaceutical Journal.
CALENDAR OF OPERATIONS.
Disbudding.—This operation does not appear to be sufficiently recognised in its proper sense as distinguished from pruning and pinching. In performing these latter operations we remove a portion of the growing shoot, in the former case the young bud is removed as soon as it can be rubbed off. These operations are therefore quite distinct, and their distinction is of much importance. Most fruit cultivators are aware that trees suffer materially by suddenly depriving them of a large portion of foliage while in active growth, and expedients are resorted to in order to render the operation less injurious. In spring when the buds burst, attention should be directed to the quantity of young shoots desirable either for fruit or uniformity of growth; these being secured all others should immediately be rubbed off. As growth proceeds luxuriant shoots are stopped or their points pinched off, removing more or less of the shoot, according to the object to be attained. If the plant is very luxuriant, more leaves may be removed and if every shoot upon a tree is operated on in this manner it amounts to a severe check on its growth. In the case of young trees, or weakly ones, where a certain form is desired, the young growing point should be bruised without removing any of the elaborating foliage, securing density of habit without any perceptible check of growth. Suppose a shoot that has grown 12 or 14 inches to be pinched back one half of its length, the uppermost bud will burst again and the others remain comparatively dormant; but allowing the same shoot to have been checked in its longitudinal growth, by pinching or bruising its extreme point, it will be found that all the lower buds will be benefitted and several additional shoots produced. We have alluded to this subject more particularly at present as we are aware of having occasionally made use of the term pinching when disbudding would have been the more appropriate expression.