The different modes of cultivating the pine-apple / From its first introduction into Europe to the late improvements of T.A. Knight, esq.

by J. C. Loudon

“Some persons may think that the Pine Apple cannot bear to be watered all over its leaves in winter, because it is of a succulent nature, and able to live long in a hot-house without being planted in earth or set in water. But, for instance, the common house-leek is of a very succulent juicy nature, and will bear the greatest heat of a hot dry summer on the warm tiles of a house: but it is well known that this plant thrives best when it gets occasional showers of rain. The case is exactly similar respecting the Pine Apple, and several other plants, of a similar nature. In regard, however, to the best method of cultivating the Pine Apple, there have been and will be persons who differ in opinion. I here give my opinion, which is founded on practice, that there is not the least danger in watering the plants plentifully all over their leaves in winter, or in any time of the year, provided there be a sufficient heat kept up in the tan bed and in the air of the house. But remember, I do not recommend watering the Pine Apple plants all over their leaves in winter as a general rule, only when it is necessary to free the plants from insects and filth; then the heat in the house among the plants must be kept strong, not lower than 70 in the morning, and raised to 85 or 90 in the course of the day.

“It is indeed evident that some of the most able writers on the culture of the Pine Apple have wanted that experience which may by practice be obtained. They have asserted, that it is impossible to keep the Pine Apple plant throughout a severe winter without the assistance of fire. But ingenious practical gardeners have ascertained, that Pine Apple plants require nothing more than a gentle heat in the tan bed, in which the pots of plants must be plunged, and a medium heat of air of about 60 degrees, to keep them through the most severe winters in England. To maintain this temperature of heat without the assistance of fire, is no difficult matter; it can be done by the assistance of horse-dung; for a dry heat is not at all necessary to preserve the plants, and to keep them in good health, in the brick beds, in which I kept Succession Pines all the year round without the aid of fire heat. The sun for about two months in winter had very little effect to warm or dry the leaves of the plants, so that during the dull months in winter, the plants were continually in a moist state, and water standing in the hearts of some of them, and the heat of the air among them was from 55 to about 65; and I do not recollect of having any of the plants die for want of heat.

Insects. By many experiments which I made, it is evident, I think, that in the process of managing and cultivating the Pine Apple, all injurious insects may be destroyed, and prevented from breeding on them, by a judicious application of the elements necessary, though in a less degree in regard to heat, for the production of any vegetables or fruits whatever. That this is true, may be proved by a reference to the state of fruits and vegetables growing, either spontaneously or assisted by cultivation, in every part of the kingdom, without the aid of artificial heat or impregnated air. For instance, the strawberry, the raspberry, and some other fruits, which grow naturally in some parts of this country, and peas, beans, cabbage, and cauliflowers in gardens, and the different sorts of corn and grass in the fields. These, in unkind seasons, we see affected by blights and by insects of various kinds, which prevent them from coming to good maturity, and make them less productive than we wish them to be. But in propitious seasons, the earth being refreshed occasionally by showers of rain, they are preserved from the inroads of insects and from blights, and are enabled to produce abundant crops, for the use of man and beast.”

Mr. M’Phail has thus the merit of being one of the first practical gardeners who freed themselves from the trammels of receipts and secrets for destroying insects. He says, “after having studiously observed the nature and causes of the vigorous growth and healthfulness of plants, and of fruit-trees of different kinds, I have been induced to believe that a fruit-tree or plant of any sort requires nothing but proper cultivation in good earth, and in a kindly climate adapted to its nature, to prevent it from being injured by insects, or by blights of any kind, and to enable it to produce, of its kind, abundant crops. However, I wish it not to be understood that I disapprove of using means of any kind to destroy insects which are injurious to plants; but I conceive that all methods used for that purpose, ought to be such as are conducive to accelerate the growth of vegetables, by having at least a tendency to purify the air, and to make the circumambient atmosphere about them congenial to their nature, unless when the destruction of the insects by the hand is effected.”

“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.