Part 10

“I had long been much dissatisfied with the manner in which the Pine Apple plant is usually treated, and very much disposed to believe the bark-bed, as Mr. Kent has stated, (_Hort. Trans._ iii. 288.) ‘worse than useless,’ subsequent to the emission of roots by the crowns or suckers. I therefore resolved to make a few experiments upon the culture of that plant; but as I had not at that period, (the beginning of October,) any hot-house, I deferred obtaining plants till the following spring. My hot-house was not completed till the second week in June (1819,) at which period I began my experiment upon _nine_ plants, which had been but very ill preserved through the preceding winter by the gardener of one of my friends, with very inadequate means, and in a very inhospitable climate. These, at this period, were not larger plants than some which I have subsequently raised from small crowns, (three having been afforded by one fruit,) planted in the middle of August, were in the end of December last; but they are now beginning to blossom, and in the opinion of every gardener who has seen them, promise fruit of great size and perfection. They are all of the variety known by the name of Ripley’s Queen Pine.

“Upon the introduction of my plants into the hot-house, the mode of management, which it is the object of the present communication to describe, commenced. They were put into pots of somewhat more than a foot in diameter, in a compost made of thin, green turf, recently taken from a river-side, chopped very small, and pressed closely, whilst wet, into the pots; a circular piece of the same material, of about an inch in thickness, having been inverted, unbroken, to occupy the bottom of each pot. This substance, so applied, I have always found to afford the most efficient means for draining off superfluous water, and subsequently of facilitating the removal of a plant from one pot to another, without loss of roots. The surface of the reduced turf was covered with a layer of vegetable mould obtained from decayed leaves, and of sandy-loam, to prevent the growth of the grass-roots. The pots were then placed to stand upon brick-piers, near the glass; and the piers being formed of loose bricks (without mortar), were capable of being reduced as the height of the plants increased. The temperature of the house was generally raised in hot and bright days, chiefly by confined solar heat, from 95° to 105°, and sometimes to 110°, no air being ever given till the temperature of the house exceeded 95°; and the escape of heated air was then, only in a slight degree permitted. In the night, the temperature of the house generally sunk to 70°, or somewhat lower. At this period, and through the months of July and August, a sufficient quantity of pigeons’ dung was steeped in the water, which was given to the Pine plants, to raise its colour nearly to that of porter, and with this they were usually supplied twice a day in very hot weather; the mould in the pots being kept constantly very damp, or what gardeners would generally call wet. In the evenings, after very hot days, the plants were often sprinkled with clear water, of the temperature of the external air; but this was never repeated till all the remains of the last sprinkling had disappeared from the axillæ of the leaves.

“It is, I believe, almost a general custom with gardeners, to give their Pine plants larger pots in autumn, and this mode of practice is approved by Mr. Baldwin. (_Cult. of Anan._ 16.) I nevertheless cannot avoid thinking it wrong; for the plants, at this period, and subsequently, owing to want of light, can generate a small quantity only of new sap; and consequently, the matter which composes the new roots that the plant will be excited to emit into the fresh mould, must be drawn chiefly from the same reservoir, which is to supply the blossom and fruit: and I have found, that transplanting fruit-trees, in autumn, into larger pots, has rendered their next year’s produce of fruit smaller in size, and later in maturity. I therefore would not remove my Pine plants into larger pots, although those in which they grow are considerably too small.

“As the length of the days diminished, and the plants received less light, their ability to digest food diminished. Less food was in consequence dissolved in the water, which was also given with a more sparing hand; and as winter approached, water only was given, and in small quantities.

“During the months of November and December, the temperature of the house was generally little above 50°, and sometimes as low as 48°, and once so low as 40°. Most gardeners would, I believe, have been alarmed for the safety of their plants at this temperature; but the Pine is a much hardier plant than it is usually supposed to be; and I exposed one young plant in December to a temperature of 32°, by which it did not appear to sustain any injury. I have also been subsequently informed by one of my friends, Sir Harford Jones, who has had most ample opportunities of observing, that he has frequently seen, in the east, the Pine Apple growing in the open air, where the surface of the ground, early in the mornings, showed unequivocal marks of a slight degree of frost.

“My plants remained nearly torpid, and without growth, during the latter part of November, and in the whole of December; but they began to grow early in January, although the temperature of the house rarely reached 60°; and about the 20th of that month, the blossom, or rather the future fruit, of the earliest plant, became visible; and subsequently to that period their growth has appeared very extraordinary to gardeners who had never seen Pine plants growing, except in a bark-bed or other hot-bed. I believe this rapidity of growth, in rather low temperature, may be traced to the more exciteable state of their roots, owing to their having passed the winter in a very low temperature comparatively with that of a bark-bed. The plants are now supplied with water in moderate quantities, and holding in solution a less quantity of food than was given them in summer.

“In planting suckers, I have, in several instances, left the stems and roots of the old plant remaining attached to them; and these have made a much more rapid progress than others. One strong sucker was thus planted in a large pot upon the 20th of July, (1819;) and that is (March 1820) beginning to show fruit. Its stem is thick enough to produce a very large fruit; but its leaves are short, though broad and numerous; and the gardeners who have seen it, all appear wholly at a loss to conjecture what will be the value of its produce. In other cases, in which I retained the old stems and roots, I selected small and late suckers, and these have afforded me the most perfect plants I have ever seen; and they do not exhibit any symptoms of disposition to fruit prematurely. I am, however, still ignorant whether any advantage will be ultimately obtained by this mode of treating the Queen Pine; but I believe it will be found applicable with much advantage in the culture of those varieties of the Pine, which do not usually bear fruit till the plants are three or four years old.

“I shall now offer a few remarks upon the facility of managing Pines in the manner recommended, and upon the necessary amount of the expense. My gardener is an extremely simple labourer, he does not know a letter or a figure; and he never saw a Pine plant growing, till he saw those of which he has the care. If I were absent, he would not know at what period of maturity to cut the fruit; but in every other respect he knows how to manage the plants as well as I do; and I could teach any other moderately intelligent and attentive labourer, in one month, to manage them just as well as he can: in short, I do not think the skill necessary to raise a Pine Apple, according to the mode of culture I recommend, is as great as that requisite to raise a forced crop of potatoes. The expense of fuel for my hot-house, which is forty feet long, by twelve wide, is rather less than sevenpence a-day here, where I am twelve miles distant from coal-pits: and if I possessed the advantages of a curved iron-roof, such as those erected by Mr. Loudon, at Bayswater, which would prevent the too rapid escape of heated-air in cold weather, I entertain no doubt, that the expense of heating a house forty-five feet long, and ten wide, and capable of holding eighty fruiting Pine plants, exclusive of grapes or other fruits upon the back wall, would not exceed fourpence a day. A roof of properly curved iron bars, appears to me also to present many other advantages: it may be erected at much less cost, it is much more durable, it requires much less expense to paint it, and it admits greatly more light.” _Hort. Trans._ iv. 72.

Mr. Knight adds, “I have not yet been troubled with insects upon my Pine plants (having only had nine plants for about as many months), and have not, of course, tried any of the published receipts for destroying them. Mr. Baldwin recommends the steam of hot fermenting horse-dung: I conclude the destructive agent, in this case, is ammoniacal gas; which Sir Humphry Davy informed me he had found to be instantly fatal to every species of insect; and if so, this might be obtained at a small expense, by pouring a solution of crude muriate of ammonia upon quick-lime; the stable, or cow-house, would afford an equally efficient, though less delicate, fluid. The ammoniacal gas might, I conceive, be impelled, by means of a pair of bellows, amongst the leaves of the infected plants, in sufficient quantity to destroy animal, without injuring vegetable life: and it is a very interesting question to the gardener, whether his hardy enemy, the red spider, will bear it with impunity.”

In the year 1820, in June, Mr. Knight had such a house as he has hinted at, erected. Its general appearance (fig. 18.), is simple, and the roof admits as much light, as any roof that can be constructed in the present state of knowledge, in the combination of wrought iron and common glass.

The plan of this house, or pit (fig. 19.), is fifty feet in length, and ten feet wide; the furnace (_a_) is placed at one end; the flue proceeds from it directly to the front parapet (_b_), and passing along close under it to the opposite end, there terminates in a chimney (_c_). Instead of a pit, a curious stage is constructed, by forming cross walls (_d_), or rather piers, connected by arches, and finished by a gradation of flat surfaces, or steps, on which the pots are placed, so as to stand as near the glass as possible (fig. 20.)

Air is admitted by shutters, which open outwards, immediately under the stone plinth of the parapet (fig. 20. _a_), in which the lower ends of the iron bars are fixed; and allowed to escape by similar shutters, opening outwards, immediately under the stone coping of the back wall (_b_), in which the upper ends of the same bars are leaded in. The path behind is on a level with the exterior surface; the width of the cross walls the length of a brick, or nine inches, and they are finished with foot tyles; the width between them is about fifteen inches, by which means, any ordinary sized person may pass from the back path to the front flue, and water or examine the plants on each side.

This house being finished, was immediately stocked with Pines, some figs, and various other plants, all of which, Mr. Knight stated verbally, in May 1821, to various members of the Horticultural Society, succeeded admirably; but by neglect of the gardener, or rather labourer, who attended them, they were killed by an over-heat in Mr. Knight’s absence from home.[1]

[1] The poor man had probably overheated himself, and comparing by his feelings the temperature of the Pinery with his own, found the latter much in its usual state; not knowing “a letter or a figure,” of course, he could not take a hint from the thermometer.

The house was again stocked with plants, which Mr. Knight, in a paper read to the Horticultural Society, in November last (1821), stated to be in a most thriving condition; and a friend of ours who had made an extensive gardening tour in the North and West of England, and who saw the Pine plants at Downton Castle, also in November, declares they appeared the most magnificent he had seen on his journey; “the plants,” he says, “were stocky, and the leaves long, broad, and green; the largest were in pots fourteen inches in diameter, and their leaves reached to the glass.”

In the paper alluded to, Mr. Knight goes on to say, “I possess more than sufficient evidence to enable me to assert with confidence, that, in the culture of the Pine Apple, the bark bed, or other hot-bed, if the plants be plunged into it, is worse than useless, after the scions, or crowns, have emitted roots; and that the Pine Apple, when treated in the manner I have recommended, is a fruit of most extremely easy culture.

“It is contended, in favour of the bark-bed, that the soil in inter-tropical climates is warm, and that the bark-bed does no more than nature does in the native climate of the Pine Apple. And if the bark-bed could be made to give a steady temperature of about ten degrees below that of the day temperature of the air in the stove, I readily admit that Pine plants would thrive better in a compost of that temperature, than in a colder. But the temperature of the bark-bed is constantly subject to excess, and defect, and I contend, and can prove, that the above-mentioned temperature is very nearly given in my stove. For the temperature of the day being about 90° or 95°, and that of the night 70°, the mould in the pots will necessarily acquire nearly the intermediate temperature of 80°. It is true, that two disturbing causes are in action; the evaporation from the mould, and porous surface of the pots, and the radiant heat of the sun. But these causes operate in opposition to each other, and probably nearly negative the operation of each other, as far as respects the temperature of the mould in the pots.

“A very great number of gardeners have within the last twelve months visited my garden. Some of these were at once convinced of the advantages of the mode of culture which they saw; others have paid a second, or third visit; but every one has ultimately declared himself a zealous convert. I have never yet seen plants of the same age equally strong, nor any producing fruit better, nor indeed so well swelled; nor any equal in richness and flavour. But I have never taken off, nor shortened a root, nor taken any other measures to retard the period of fructification, with the prospect of obtaining larger fruit; and my plants have almost always showed fruit when fourteen or fifteen months old, though propagated from small and young suckers, or crowns. A great part of my Queen Pines (I have hitherto scarcely ever cultivated any other varieties) have, however, at that age, shown fruit with eight, and some with nine rows of pips; and I often see fruit of less weight growing upon plants of nearly double that age. Whether I shall be able to retard the period of fructification, or not, I have yet to learn; but I believe, I shall succeed by crowding my plants close together, so that each may receive less light.

“Pine plants will, however, grow perfectly well in composts of different kinds; but I have found that they have succeeded best when the materials have been fresh, and retaining their organic form, particularly if the pots be large, relatively to the size of the plants, which, I think, they always ought to be, for the mode of culture recommended. I have used, with advantage, the haulm of beans cut into lengths of about an inch.

“Very contrary to the conclusions which I should have been led to draw from writings upon the culture of the Pine Apple, I have constantly found that my plants succeed best in the part of my house where the flue first enters, and where the temperature is very high, varying from about 85° to 105°, and the air excessively dry. I have pointed out this circumstance to every gardener, whom I have seen in my house, and all have expressed their astonishment at the circumstance. I expected that this excess of heat would have occasioned the plants to show fruit prematurely, but this has not occurred in a single instance. What would be the quality of the fruit, if it were to be ripened in so high a temperature, I have not yet had an opportunity of knowing.

“In raising young plants, I have deviated from the ordinary mode of practice by breaking off the suckers when very young; that is, when they are not more than four or five inches long. The fruit is much benefited by their absence; and the cuttings, if placed very close together in a hot-bed, are made to emit roots with little trouble, and afford better plants than they do when they are suffered to remain long upon the parent stem. When the whole are removed at an early period, one or more very strong suckers usually spring out below the level of the soil; and from these, suffering only one to remain attached to the parent stem, and preserving the roots as entire as possible, I have propagated with much advantage, and have obtained plants which showed fruit strongly at seven months, dating from the period at which the sucker appeared, like a strong head of asparagus, at the surface of the soil.

“The success of my experiments, in the first house which I erected, (and to which the foregoing account exclusively refers,) led me to erect another house (figs. 18. 19. and 20.) in the summer of 1829. In this I attempted to obtain the greatest possible influence of light, and command of solar heat; inferring, from having observed Pine Apples to ripen tolerably well with very little light, that I should be able to ripen them in perfection late in the autumn, and early in the spring, particularly at the latter period, in which, alone, I set a very high value upon the species of fruit. The height of the back wall (fig. 20.) of this house is eight feet six inches, and that of the front wall is one foot six inches, and its breadth ten feet, inside measure, with an iron curvilinear roof, (fig. 18.) of the kind of bar invented by Mr. LOUDON, of Bayswater. This house is fifty feet long, (fig. 19.) and capable of containing two hundred fruiting Pine plants. The curvature of the roof rises just one foot in twelve. The glass is laid in a composition of two parts white lead, with oil, and three of flint sand, and the overlaps of the glass are closely filled with the same material. It is, consequently, very nearly air-tight; and no means are given for the air to enter, or escape, except by apertures immediately under the copings of the front and back wall, (_a_ and _b_, fig. 20.) which can be efficiently closed at any time. It is, consequently, an instrument of very great power, and requiring, of course, much attention to ventilation: of which I had rather a lamentable proof in the last spring, when my plants were all burned, and spoiled in a few hours; the person who had the care of them having left them in a bright day closely shut up. The fault was not, however, in any degree in the house, for the plants were, previously, much the strongest, and the best I ever saw; and I believe, they would have afforded most beautiful fruit. I furnished the house again with plants as expeditiously as I could, chiefly in July; and I have since kept the temperature of it nearly between 70° and 95°, with a wish to make the plants show fruit and blossom in the present month (October.) In this, I have in part succeeded, though many of my plants have flowered a fortnight or three weeks sooner than I wished. The fruit is swelling well, and, I believe, will receive sufficient light through the winter to enable it to ripen in much perfection. The excellence of a few Pine Apples, which ripened in this house in the last winter, leads me almost to doubt, whether the fruit in it will not ripen better, early in the spring, than in the middle of the summer, for I have observed that this species of plant, though extremely patient of high temperature, is not, by any means, so patient of the action of very continued bright light, as many other plants: and much less so than the Fig and Orange tree: possibly, having been formed by nature for inter-tropical climates, its powers of life may become fatigued, and exhausted by the length of a bright English summer’s day in high temperature. Being a plant of low stature, nature has also probably given it the power to ripen its fruit and seed, in the shade of other plants, in its native climate; and I discovered in the last summer, that it possesses the power to ripen its fruit perfectly in a lower temperature than I previously thought it capable of growing in.

“In the month of June, I gave a couple of Pine plants, which had shown fruit at six months old, and were of small size, and no value, to a child of one of my friends, to be placed in a conservatory, in which no fires were kept during the summer. In July, a storm of hail destroyed nearly, or fully, half the glass of the conservatory; and its temperature, through the summer and autumn, had been so low, that the Chasselas grapes in it were not ripe in the second week in September. In the second week of the present month (October) one of the Pine Apples became ripe, having previously swollen to a most extraordinary size, comparatively with the size of the plant; and upon measuring accurately the comparative width of the fruit, and of the stem, I found the width of the fruit to exceed that of the stem in the proportion of seven and three-quarters to one. The fruit had, of course, been propped during all the latter part of the summer, the stem being wholly incapable of supporting it. The taste and flavour of this fruit were excellent, and the appearance of the other, which is not yet ripe, and is of a larger size, is still more promising. I purpose to profit by this result in the next summer; and I hope to be able to communicate some further information to the Society in the autumn. I feel perfectly confident, that if the roots of these plants had grown in a hot-bed of any kind, their sap would have been impelled into other channels; and that their fruit would not have attained, in any degree, the state of perfection which I have described.”