Part 6
“Every insect has its proper plant, or tribe of plants, which it naturally requires for its nourishment, and on which it generally lays its eggs, and that on the most concealed parts of the plant; and the plant, and insect which attacks it, are always natives of the same climate, and therefore endure the same degrees of heat and cold; consequently, when plants are attacked by their natural tribe of insects, it is an exceedingly nice and curious operation to exterminate them without injuring the plants, or stopping them in their natural growth. But observing that insects increase rapidly in hot dry weather, and that they appear impatient of moisture, was the means of inducing me try which would bear the greatest heat and live.”
“To ascertain what degree of heat a Pine Apple plant can endure without destroying it, I filled four vessels with hot water. The water in the first vessel was 130 degrees hot; that in the second 140; that in the third 145; that in the fourth 150. Into each of these vessels I put a few Pine plants, divested of their roots, of their fibrous roots, and suffered them to remain in the water about an hour. The plants which had been immersed in the water heated to 140 and 145 degrees, were a little hurt in the extremities of their leaves, but after being dried in the hot-house, they were planted, and grew as vigorous as if they had not been put into hot water; the plants put into water 130 degrees warm were not in the least injured; but those put into water heated to 150 degrees were entirely destroyed.
“By this experiment I ascertained that a vegetable can endure, without hurting it, 130 degrees of heat, according to the degrees on Fahrenheit’s thermometer. I am inclined to think that no animal is able to endure such a heat and live. Undoubtedly, insects increase rapidly in hot weather in the open air, especially on the peach tree, and on other trees, against warm walls, both in the spring and summer months; and they increase most rapidly in dry weather; but the heat in the open air against walls seldom rises to 100 degrees. And in the hottest countries in the world, where vegetables and animals exist, the heat in the shade seldom rises to blood heat, which is about 97. Having considered these things, and ascertained that a plant can endure a heat of 130 degrees, I determined to try another experiment, that is, to ascertain whether heat and water would destroy insects, and keep plants alive. I therefore thought of, and determined to try, the following method:
“In the month of June I selected about twenty large Pine plants, some of which had green fruit on them, and their leaves, fruit, and roots, were almost covered with insects. These plants I plunged in a tan bed, with a very gentle heat in it. The tan bed was in a brick frame designed for rearing succession plants: it was nearly five feet wide, twenty feet long, and the glass frames were close and in good repair. These plants I watered frequently and plentifully, sometimes twice a day, with water not less than 70 or 80 degrees, and sometimes 100, warm: in short, I kept the plants constantly in a moist air, by plentiful waterings without measure; and, excepting the time of giving water, I kept the lights constantly close shut down, even in the hottest sunshine, without shading the plants. In this frame I had no thermometer, but the heat was, I think, sometimes about two or three o’clock in the afternoon, upwards of 120 degrees. This great heat and much moisture caused the plants to grow most vigorously; and having subjected them to the said mode of management for a few weeks, the insects, in the course of that time, were totally destroyed, many of them lying dead on the leaves and fruit. In the spring-time, before this operation, the plants had been strewed with sulphur, which, at least, is a harmless dressing to plants of any kind, and probably may be of use in preventing insects from breeding numerously, or the means of depriving them of part of their natural food. This circumstance, however, I just here mention, because, from experiments which I have tried since then, it is probable that the effluvia arising from flour of sulphur, being scattered on the leaves, or about in the hot-house, in conjunction with heated air and moisture, may more suddenly destroy insects than heat and moisture alone; but it ought to be remembered, that if sulphur be by any means set on fire in a confined place, among plants of any kind, it will either totally destroy or greatly injure them.
“Being satisfied with my success in the above-mentioned experiment, of having totally destroyed the insects on these plants without hurting them, I hesitated not to begin to water the whole of the plants under my care, whenever they wanted it, all over their leaves and fruit, with water about 85 degrees warm. This process I continued to practise for several months, during which time I do not recollect that the thermometer was ever below 70, and in sunshine it was raised sometimes to upwards of 110 degrees. I continued this practice longer perhaps than was absolutely necessary, but I was determined to destroy the whole of the insects in the house, whether on the plants, or in the tan, or in any part of the house; and this I certainly did accomplish effectually. Thus, by this easy, and not unnatural, mode of management, the plants became perfectly free of insects; they were perfectly cleansed of all filth; they grew vigorously; and the fruit swelled fine to a good size. After this I had several times Pine Apple plants from abroad, and out of hot-houses at home, full of insects, which, by the means that I have, without reserve, described, I effectually destroyed, and made the plants grow very fast indeed.”
“If Pine Apple plants be kept in a strong vigorous growing state by giving them plenty of heat, and water applied occasionally all over their leaves, whether they be in frames heated with dung, or in hot-houses heated by a fire, a few insects will do them little hurt. But if the methods which I have given for cultivating the Pine Apple plant be adopted, I am persuaded all sorts of injurious insects natural to these sorts of plants will disappear on them.
“When we see human creatures lean in body for want of a sufficiency of wholesome food, or, for want of cleanliness, lice and fleas breed upon them; and poverty in cattle for want of food has the same effect on them. Similar causes in vegetables has a similar effect, so that when Pine Apple plants are in a state of poverty, for want of a sufficiency of good earth, or of heat, or of water, insects natural to them, if there be any of them in the hot-house, will breed rapidly on them and hurt them. Those insects which naturally breed and live on the Pine Apple plant, appear to delight in a dry dirty situation. Where Pine Apples grow naturally and produce large fruit, they are not free of insects; and though plants be free of insects, they will not grow well, nor produce fine fruit, unless they get enough of good earth, sufficient heat, and be watered plentifully.”
_Fruit produced._ The green, and some other sorts of Pine, Mr. M’Phail “ripened in a shorter period of time than two years after planting,” (_Gard. Rem._ 87.) but some large kinds he found required three seasons, as the black Antigua, Jamaica, and Ripley. His object was to have his fruit come in for use between May and October, for he very justly remarks, that “the fruit of the Pine Apple, if it happen to appear ripe in winter, will have its flavour insipid.” He therefore recommends, that such plants as show fruit in September or October, had better be cast away, unless there be plenty of room for them in the hot-house; in that case they may be retained by way of experiment, and to obtain young plants from them. (_Gard. Rem._ 98.)
SECT. VIII.
_Culture of the Pine Apple in Fifeshire, by Mr. Walter Nicol._
Mr. Nicol was from 1790 to 1800, the best grower of the Pine Apple in Scotland; he had afterwards much experience as a constructor of hot-houses; and extensive observation of the practice of the best gardeners of the north.
_Form of House._ “Pineries,” he says, “are, and may be, very differently constructed; and we find plants thriving, and plants not thriving, in all kinds of stoves, pits, &c. The culture of Pine Apples is attended with a heavier expense than that of any other fruit under glass; especially if they be grown in lofty stoves, the erection of which is very expensive, and the keeping up proportionally more so, than that of humbler stoves, or flued pits.
“But, independently of all considerations of expense (which may not be valued by some, provided they can obtain good fruit), Pine Apples may certainly be produced in as great perfection, if not greater, and with infinitely less trouble and risk, in flued pits, if properly constructed, than in any other way. I would therefore have the Pinery detached from the other forcing-houses, and to consist of three pits in a range; one for crowns and suckers, one for succession, and one for fruiting plants. The fruiting-pit to be placed in the centre, and the other two, right and left; forming a range of a hundred feet in length; which would give Pine Apples enough for a large family.
“The fruiting-pit to be forty feet long, and ten feet wide, over walls; and each of the others to be thirty feet long, and nine feet wide, also over walls. The breast-wall of the whole to be on a line, and to be eighteen inches above ground. The back-wall of the centre one to be five feet, and of the others, to be four and a half feet higher than the front. The front and end flues to be separated from the bark-bed by a three-inch cavity, and the back flues to be raised above its level.
“The furnaces may either be placed in front, or at the back, according to conveniency; but the strength of the heat should be first exhausted in front, and should return in the back-flues. The fruiting-pit would require two small furnaces, in order to diffuse the heat regularly, and keep up a proper temperature in winter; one to be placed at each end; and either to play, first in front, and return in the back; but the flues to be above, and not alongside of one another; as in that latter way they would take up too much room. The under one to be considered merely as an auxiliary flue, as it would only be wanted occasionally.
“None of these flues need be more than five or six inches wide, and nine or ten deep. Nor need the furnaces be so large by a third, or a fourth part, as those for large forcing-houses; because there should be proper oil-cloth covers for the whole, as guards against severe weather, which would be a great saving of fuel.
“The depth of the pits should be regulated so as that the average depth of the bark-beds may be a yard below the level of the front flues; as to that level the bark will generally settle, although made as high as their surfaces, when new stirred up. If leaves, or a mixture of leaves with dung, are to be used instead of bark, the pits will require to be a foot, or half a yard deeper.
“It may be thought too much to insinuate, that those who have large Pineries should turn them to other purposes, and erect such as are described above. There cannot be a doubt, however, respecting the satisfaction that would follow, if to have good fruit at an easy rate were the object. I have given designs for no other kinds of new Pineries these six years past, but such as these; with some variations respecting extent, however, in order to suit different purses.”
_Soil._ Vegetable mould, strong brown loam, pigeons’ dung, and shell-marl, are Mr. Nicol’s ingredients. “The vegetable mould used is that from decayed tree-leaves, and those of the oak are to be preferred; but when a sufficient quantity of them cannot be had, a mixture with those of the ash, elm, birch, sycamore, &c. or indeed any that are not resinous, will answer very well. In autumn, immediately as the leaves fall, let them be gathered, and be thrown together into an heap; and let just as much light earth be thrown over them as will prevent them from being blown abroad by the wind. In this state let them lie till May, and then turn them over and mix them well. They will be rendered into mould fit for use by the next spring; but from bits of sticks, &c. being among them, they will require to be sifted before using. Strong brown loam is the next article. This should consist of the sward of a pasture, if possible; which should, previous to using, be well reduced, by exposing it a whole year to the action of the weather. Pigeon-dung, also, that has lain at least two whole years in an heap, has been frequently turned, and well exposed to the weather, is to be used. Likewise shell-marl. And, lastly, sea or river gravel, which should be sifted, and kept in a dry place; such part of it as is about the size of marrowfat peas is to be used. This is the proportion: for crowns and suckers, entire vegetable mould, with a little gravel at bottom, to strike in; afterwards, three-fourths vegetable mould, and one-fourth loam, mixed with about a twentieth part gravel, and two inches entire gravel at bottom, till about a year old. For year-olds, and till shifted into fruiting-pots, one-half vegetable mould, one-half loam; to which add a twentieth part gravel, and as much shell-marl, with three inches clean gravel at bottom. For fruiting-plants, one-half loam, a fourth part vegetable mould, and a fourth part pigeon-dung; to which add marl and gravel as above, and lay three or four inches of clean gravel at bottom. The above compositions are what I formerly used for Pine-plants with much success; and are what may be reckoned good medium soils for the production of Pine Apples.”
_General Management._ Mr. Nicol plants his suckers in summer and autumn as the fruit is gathered, sticking them into the front part of the bark-bed, “where they will strike root as freely as any where. If a large proportion of the crop come off early, the crowns and suckers may be potted at once, and plunged into the nursing-pit; or they may be twisted from off the stocks, and may be laid by, in a dry shed or loft for a few days, till the other operations in the Pinery be performed, and the nursing-pit be ready to receive them and the crowns, (collected as the fruit have been gathered;) which, if rooted, may be potted, and may be placed for the above time, either in a frame, or in a forcing-house of any kind, as they will sustain no injury, though out of the bark-bed for so short a time. Such crowns as have not struck root, may be laid aside with the suckers.
“With respect to the time for taking off the suckers, it is when the bottom part becomes brown; and they are then easily displaced by the thumb, after having broken down the leaf immediately under them. But, indeed, by the time the fruit is ripe, all suckers of the stem are fit for taking off, though they will sustain no injury by being left on, even for a month, but rather improve, if the stock be healthy, and if it be well watered. Suckers that rise from the root always have fibres, and may be taken off at any time; but, as they are tardy of fruiting, they should not be taken into the stock, unless in a case of necessity.
“Some think it necessary to dry, or win, all crowns and suckers before potting them, and for that purpose lay them on the shelves, &c. of the stove for a week or ten days. By this treatment, they certainly may be hurt, but cannot be improved, provided they have been fully matured before being taken from off the fruit or stocks, and that these have previously had no water for about ten days. They will succeed as well, if planted the hour they are taken off, as if treated in any other way whatever; and I only advise their being laid aside as above, as being a matter of conveniency.”
In preparing the suckers and unstruck crowns for potting, he twists off a few of the bottom leaves, and pares the end of the stump smooth with the knife. “Then fill pots of about three or four inches diameter, and five or six inches deep, (the less for the least, and the large for the largest plants), with very fine, light earth, or with entire vegetable mould of tree leaves, quite to the brim; previously placing an inch of clean gravel in the bottom of each, and observing to lay in the mould loosely. Thrust the large suckers down to within two inches of the gravel, and the small ones and crowns, two inches into the mould; firming them with the thumbs, and dressing off the mould, half an inch below the margin of the pots. Then plunge them into the bark-bed, quite down to, or rather below the brim, especially of the smaller pots. If the pots be placed at the clear distance of three or four inches from each other, according to the sizes of the plants, they will have sufficient room to grow till next shifting.”
The temperature of the nursing-pit in January with fire heat, he keeps as near as possible to 65° mornings and evenings; and in sunshine, on good days, it may be allowed to rise to about 70°. In March from 70° to 80°; and after newly potting and plunging, unstruck crowns and suckers to 80° or 85°.
To save fuel, he covers up the Pine pits when fires are used, every evening after sunset, either with double mats, or with a thick canvas cover, mounted on rollers. This cover he removes by sun-rise in the morning, unless the weather be very severe; in which case he leaves it on during the day. By the judicious use of this cover, he finds “a considerable deal of fuel may be saved.”
As to water, he says, “nurse plants require very little, perhaps once in eight or ten days, or even at greater intervals, if the weather be moist and hazy. It is safer, in winter, to give too little, rather than too much water to Pine-plants; nor should they be watered over head at this season. They should be watered in the forenoon of a sunny day, at this time of the year, in order that any water spilt on the bark, or in the hearts of the plants, may be exhaled by the heat of the sun, and by an extra quantity of air purposely admitted. This precaution, however, is only necessary for the sake of such crowns and suckers as have been struck late last season, and are not very well rooted; such being more apt to damp off than others that are better established.” In summer he supplies water regularly and plentifully once in three days; giving the proper quantity at root, and then a dewing over the leaves. He waters frequently with the drainings of the dunghill.
Air he admits to the nursing-pits every good day. Even in hard frost, when the sun shines, two or three of the lights should be slipped down, to let the rarified air escape at top. After potting unrooted offsets, he gives no air till the heat begin to rise in the bark-bed; but as the plants indicate their having made roots, he gives air during sunshine, so as to keep down the thermometer to 85° or 80°.
Suckers planted in summer he shifts or re-pots in the following March. He says, “Let them be shaked out entirely; the balls be quite reduced; the roots be trimmed of all straggling and decayed fibres; and let them be replaced in the same, or in similar pots. The proper size of pots, however, in which to put crowns and suckers struck last season, is about four inches inside diameter at top, and six inches deep. A little clean gravel should be laid at the bottom of each pot, in order to drain off extra moisture; and this should be observed in the potting of Pine-plants of all sorts. I have generally observed, that if the bark heat be not violent, the plants will push very strong fibres into this stratum of gravel, in which they seem to delight. I therefore generally make it two inches thick in small pots, and three or four in larger ones, less or more, according to their size. From the time I first adopted this mode of potting, I hardly ever had an instance of an unhealthy plant; and this very particular, together with that of keeping the plants always in a mild bottom-heat, is of greater importance in the culture of Pines, than all the other rules that have been given respecting them, out of the ordinary way. The roots of Pines seem to delight in gravel; and I have been careful to introduce it into the mould for plants of all ages. I generally used small sea-gravel, in which was a considerable proportion of shells, or chips of shells, with other particles of a porous nature; and I have uniformly observed the finest fibres cling to these, and often insinuate themselves through the pores, or embrace the rougher particles. Therefore, if sea gravel can be obtained, prefer it; and next, river gravel; but avoid earthy pit gravel, and rather use sharp sand, or a mixture of pounded-stone, chips, and brick-bats. The plants being re-potted, plunge them in the bark-bed again, quite down to the rims of the pots, keeping them perfectly level. Eight or nine inches from centre to centre will be distance sufficient. When they are all placed, give a little aired water, to settle the earth about their roots. This need not be repeated till the heat in the bed rise to the pots, after which, as the plants will now begin to grow freely, they must be watered at the root once in four or five days; and they may have a dewing over head, from the fine rose of a watering-pot, occasionally, if the weather be fine.”
In May, Nicol again shifts, but the plants are not to be shaked out at this time, but are to be shifted, balls entire, into pots of about six inches diameter, and eight inches deep. “If the roots be anywise matted at bottom, or at the sides, they must be carefully singled out; and in potting, be sure that there be no cavity left between the ball and the sides of the new pot. In order the more effectually to prevent which, use a small, blunt-pointed, somewhat wedge-shaped, stick, to trindle in the mould with; observing that it be in a dry state, and be sifted fine; and also to shake the pot well, (potting on a bench or table), the better to settle the earth about the ball. Pots of this size should be filled to within half an inch of their brims, (the balls being covered about an inch with fresh earth), as the whole will settle about as much, and so leave a full inch for holding water, which is enough. In preparing the plants for potting, observe to twist off a few of the bottom leaves, as they always put out fine roots from the lower part of the stem. Also, before letting the plant out of hand, trim off the points of any leaves that may have been bruised or anywise injured in the shifting. Replunge the pots to the brim, as before, observing to keep them quite level, at the distance of fifteen inches from centre to centre of the plants on a medium; then give a little water, which need not be repeated till the heat rise to the pots.”
In November, he shifts such others whose roots have filled their pots, and have become anywise matted. “Examine any you suspect to be so, and let them be shifted into pots of the next size immediately above those they are in; keeping the balls entire, and only singling out the netted fibres at bottom. The rest should be trimmed of any dead leaves at bottom of their stems, and should have a little of the old mould taken from off the surface of the pots; which replace with fresh earth; filling the pots fuller than usual, as but little water will be required till next shifting time in the spring. The whole should then be replaced in the bark-bed as before, and should be plunged quite to the rims of the pots; giving a little water to settle the earth about their roots, which need not be repeated till the heat rise in the bed.”