CHAPTER III.
SOWING SEEDS—PLANTING BULBS AND
TUBERS—TRANSPLANTING AND WATERING.
Sowing Seeds.—The principal points to be attended to in sowing seeds are, first, to prepare the ground so that the young and tender roots thrown out by the seeds may easily penetrate into it; secondly, to fix the seeds firmly in the soil; thirdly, to cover them, so as to exclude the light, which impedes vegetation, and to preserve a sufficiency of moisture round them to encourage it; and, fourthly, not to bury them so deeply as either to deprive them of the beneficial influence of the air, or to throw any unnecessary impediments in the way of their ascending shoots.
The preparation of the soil has been already described in the chapter on digging, and the reasons why it is necessary have been there given; but why seeds should be firmly embedded in it, seems to require explanation. It is well known that gardeners, before they either sow a bed in the kitchen-garden, or a patch of flower-seeds in the flower-garden, generally “firm the ground,” as they call it, by beating it well with the back of the spade, or pressing it with the saucer of a flower-pot; and there can be no doubt that this is done in order that the seeds may be firmly imbedded in the soil. When lawns are sown with grass-seeds also, the seeds are frequently rolled in, evidently for the same purpose. The only question, therefore, is, why is this necessary; and the answer appears to be, that a degree of permanence and stability is essential to enable nature to accommodate the plant to the situation in which it is placed. When there is this degree of permanence and stability, it is astonishing to observe the efforts that plants will make to provide for their wants; but without it, seeds will not even vegetate. Thus we often see large trees springing from crevices in apparently bare rocks; while not even a blade of grass will grow among the moving sands of a desert.
The reasons for the second and third points of covering the seeds, and yet not covering them too deeply, appear more obvious; and yet they also require a little explanation. The seeds are covered to keep them in darkness, and to retain round them a proper quantity of moisture; not only to make them swell and begin to vegetate, but to enable the roots to perform their proper functions; since, if exposed to the air, they would become dry and withered, and lose the power of contracting and dilating, which is essential to enable them to imbibe and digest their food. Burying the seeds too deeply is obviously injurious in impeding the progress of the young shoot to the light; and in placing it in an unnatural position. When a seed vegetates too far below the surface, a part of the stem of the plant must be buried; and this part not being intended to remain under-ground, is not protected from the dangers it is likely to meet with there. It is thus peculiarly liable to be assailed by slugs and all kinds of insects, and to become rotten by damp, or withered by heat. It is also very possible to bury a seed so deeply as to prevent it from vegetating at all. The ground has more of both warmth and moisture near the surface than at a great depth, as it is warmed by the rays of the sun, and moistened by the rain; but besides this, seeds will not vegetate, even when they are amply supplied with heat and moisture, if they are excluded from the influence of the air. Every ripe seed in a dry state is a concentration of carbon, which, when dissolved by moisture, and its particles set in motion by heat, is in a fit state to combine with the oxygen in the atmosphere, and thus to form the carbonic acid gas which is the nourishment of the expanding plant. For this reason, seeds, and newly sprung-up plants do not want to be supplied with manure, and air is much more essential to them: they have enough carbon in their cotyledons or seed-leaves, and they only want oxygen to combine with it, to enable them to develope their other leaves; and this is the reason why young plants, raised on a hotbed, are always given air, or they become yellow and withered. Light absorbs the oxygen from plants, and occasions a deposition of the carbon. Thus seeds and seedlings do not require much light; it is indeed injurious to them, as it undoes in some degree what the air has been doing for them: but young plants, when they have expanded two or three pairs of leaves, and when the stock of carbon contained in their cotyledons, or seed-leaves, is exhausted, require light to enable them to elaborate their sap, without which the process of vegetation could not go on. Abundance of light also is favourable to the development of flowers, and the ripening of seeds; as it aids the concentration of carbon, which they require to make them fertile. The curious fact that seeds, though abundantly supplied with warmth and moisture, will not vegetate without the assistance of the air, was lately verified in Italy; where the Po, having overflowed its banks near Mantua, deposited a great quantity of mud on some meadows; and from this mud sprang up a plentiful crop of black poplars, no doubt from seeds that had fallen into the river from a row of trees of that kind, which had formerly grown on its banks, but which had been cut down many years previously. Another instance occurred in the case of some raspberry seeds found in the body of an ancient Briton discovered in a tumulus in Dorsetshire. Some of these seeds were sown in the London Horticultural Society’s Garden at Turnham Green, where they vegetated, and the plants produced from them are still (1839) growing. Numerous other nearly similar instances, will be found in Jesse’s Gleanings, Hooker’s Botanical Miscellany, and numerous other works. Steeping seeds in oxalic acid, &c. to make them vegetate, is efficacious; as there is a speedier combination between the carbon in the seeds, and the oxygen in the acid, than can be effected by the ordinary agency of the air in parting with its oxygen to them.
Planting bulbs and tubers bears considerable analogy to sowing seeds. The bulb or tuber may indeed be considered as only a seed of larger growth, since it requires the combined influence of air, warmth, and moisture to make it vegetate, and then it throws out a stem, leaves, and roots like a seed. There is, however, one important difference between them; the seed expends its accumulated stock of carbon in giving birth to the root, stem, and leaves, after which it withers away and disappears; while the bulb or tuber continues to exist during the whole life of the plant, and appears to contain a reservoir of carbon, which it only parts with slowly, and as circumstances may require. Though bulbs and tubers have here been mentioned as almost synonymous, modern botanists make several distinctions between them. The tunicated bulbs, such as those of the hyacinth and the onion, and the squamose bulbs, such as those of the lily, they consider to be underground buds; while tubers such as those of the dahlia, and the potatoe, and solid bulbs or corms, such as those of the crocus, they regard as underground stems.
These distinctions, however, though they may be interesting to the botanist and vegetable physiologist, are of little or no use in practice; the practical gardener treating bulbs and tubers exactly alike, and planting them as he would sow a seed: that is to say, he fixes them firmly in the ground, and covers them, but not so deeply as to exclude the air. In preparing a bed for hyacinths or other tunicated bulbs, it is necessary to pulverize the soil to a much greater depth than for ordinary seeds; as the fibrous roots of the hyacinth descend perpendicularly to a considerable depth, as may be seen when these plants are grown in glasses. The very circumstance of growing hyacinths in glasses, where they vegetate and send down their roots exposed to the full influence of the light, appears contrary to the usual effects of light on vegetation; and indeed the plants are said generally to thrive best, when the glasses are kept in the dark till the roots are half grown. However this may be, it is quite certain that hyacinths in glasses should never be kept in darkness when their leaves begin to expand; as, if there be not abundance of light to occasion rapid evaporation from the leaves, the plants will soon become surcharged with moisture from the quantity constantly supplied to their roots; and the leaves will turn yellow, and look flaccid, and unhealthy, while the flowers will be stunted, or will fall off without expanding.
Transplanting.—The points to be attended to in transplanting, are—care in taking up, to avoid injuring the spongioles of the roots; planting firmly to enable the plant to take a secure hold of the soil; shading to prevent the evaporation from the leaves from being greater than the plant in its enfeebled state can support; and watering that it may be abundantly supplied with food in its new abode. The first point is to avoid injuring the roots, and it is only necessary to consider the construction and uses of these most important organs to perceive how impossible it is for the plant to thrive, unless they are in a perfectly healthy state. Roots generally consist of two parts; the main roots which are intended to act as grappling irons to enable the plants to take a firm hold of the ground, and the fibrous roots which are intended to supply the plant with nourishment. These fibrous roots are most liable to receive injury from transplanting, as they are covered with a very fine cellular integument, so delicate in its texture as to be very easily bruised; and they each terminate in a number of small pores of extraordinary delicacy and susceptibility, which act as little sponges to imbibe moisture for the use of the plant. It is well known that these spongioles are the only means which the plant possesses of imbibing food, and that if they should be all cut off, the plant must provide itself with others, or perish for want of nourishment. These spongioles are exactly of the nature of a sponge; they expand at the approach of moisture, and when surcharged with it, they contract, and thus force it into the fibrous roots, the cellular integument of which dilates to receive it; hence the moisture is forced, by capillary attraction, as it is supposed, into the main roots, and thence into the stem and branches of the plant; circulating like the blood, and after it has been elaborated in the leaves, as the blood is in the lungs, dispensing nourishment to every part as it goes along.
The roots have no pores but those forming the spongioles; and only the fibrous roots appear to possess the power of alternate dilation and contraction, which power evidently depends on their cellular tissue being in an entire and healthy state. Thus, it is quite evident that if the spongiole of any fibril be crushed, or even the cellular tissue injured, it can no longer act as a mouth and throat to convey food to the plant. When this is the case, the injured part should be instantly removed; as its elasticity can never be restored, and it is much better for the plant to be forced to throw out a new fibril, than to be obliged to carry on its circulation weakly and imperfectly with a diseased one. Whenever a plant is taken up for transplanting, its roots should therefore be carefully examined, and all their injured parts cut off, before it is replaced in the ground. Deciduous plants, and particularly trees and shrubs, are generally transplanted when they are without their leaves; because at that season they are in no danger of suffering from the effects of evaporation.
Shading is necessary after transplanting all plants that retain their leaves; as the evaporation from the leaves, if exposed to the full action of the light, would be greater than the plant could support with a diminished number of spongioles. If it were possible to transplant without injuring the fibrils, and if the plant were immediately supplied with plenty of water, shading would not be required; and, indeed, when plants are turned out of a pot into the open garden without breaking the ball of earth round their roots, they are never shaded. The reason for this is, that as long as a plant remains where it was first sown, and under favourable circumstances, the evaporation from its leaves is exactly adapted to its powers of absorbing moisture; it is therefore evident, that if, by any chance, the number of its mouths be diminished, the evaporation from its leaves should be checked also, till the means of supplying a more abundant evaporation are restored.
The use of watering a transplanted plant, is as obvious as that of shading. It is simply to supply the spongioles with an abundance of food, that the increased quantity imbibed by each, may, in some degree, supply their diminished number.
All plants will not bear transplanting, and those that have tap-roots, such as the carrot, are peculiarly unfitted for it. When plants having tap-roots are transplanted, it should be into very light soil, and what is called a puddle should be made to receive them. To do this, a hole or pit should be formed, deeper than the root of the plant, and into this pit water should be poured and earth thrown in and stirred so as to half-fill it with mud. The tap-rooted plant should then be plunged into the mud, shaking it a little so as to let the mud penetrate among its fibrous roots, and the hole should be filled in with light soil. The plant must afterwards be shaded longer than is usual with other plants; and when water is given, it should be poured down nearer to the main root than in other cases, as the lateral fibrous roots never spread far from it. Plants with spreading roots, when transplanted, should have the pit intended to receive them made shallow, but very wide in its diameter; so that the roots may be spread out in it to their fullest extent, except those that appear at all bruised or injured, which, as before directed, should be cut off with a sharp knife.
It is a general rule, in transplanting, never to bury the collar of a plant; though this rule has some exceptions in the case of annuals. Some of these, such as balsams, send out roots from the stem above the collar; and these plants are always very much improved by transplanting. Others, the fibrous roots of which are long and descending, such as hyacinths, bear transplanting very ill, and when it is absolutely necessary to remove them, it should be done with an instrument called a transplanter; which may be purchased in any ironmonger’s shop, and the use of which is to take up a sufficient quantity of earth with the plant to remove it without disturbing the roots.
The uses of transplanting are various. When seeds are sown, and the young plants from them begin to make their appearance, they will generally be found to be much too thick; and they will require thinning, either by drawing some of them out and throwing them away, or by removing them to another bed by transplanting. This, in the case of annuals, is called by the gardeners pricking out. The young plants are taken up with a small trowel, and replaced in a hole made for them, and the earth pressed round them, with the same trowel; the only care necessary being to make them firm at the root, and yet to avoid injuring the tender spongioles. Gardeners do this with a dibber, which they hold in the right hand, and after putting in the young plant with the left hand, they press the earth round it with the dibber in a manner that I never could manage to imitate. I have found the trowel, however, do equally well, though it takes up rather more time.
Another use of transplanting is to remove trees and shrubs from the nursery to where they are permanently to remain. To enable this to be done with safety, the trees and shrubs in commercial nurseries are prepared by being always removed every year, or every other year, whether they are sold or not. The effect of these frequent removals is to keep the roots short, and yet provided with numerous spongioles; for as they are always pruned on every removal, and as the effect of pruning is to induce the roots pruned to send out two short fibrous roots armed with spongioles, in the place of every one cut off, the roots, though confined to a small space, become abundant. The reverse of this is the case, when plants are left in a natural state. It has been found, from experience, that plants imbibe more food than they absolutely require as nourishment from the soil, and that they eject part of it; also that their roots will not reimbibe this excrementitious matter, but are continually in search of fresh soil. To provide for this the fibrous roots are possessed of an extraordinary power of elongating themselves at their extremities; and thus the roots of even a small plant, left to nature, will be found to extend to a great distance on every side. It is obvious that this elongation of the roots must greatly increase the difficulties attending transplanting. Where the roots extend to a distance from the tree, a greater extent of ground has to be disturbed, both to take up the plant, and to make a pit for replanting it; the risk of injuring the fibrous roots is increased; and, as nearly all the spongioles will require to be cut off, from the great length of the roots, and consequent greater difficulty which will attend taking them up entire, the plant will be nearly famished before new spongioles can be formed to supply it with food. All these dangers are avoided by the nursery system of transplanting; while the inconvenience of confining the roots to so small a space is obviated, by placing the plant, every time it is transplanted, in fresh soil.
It is customary, when trees or shrubs are transplanted to the places where they are permanently to remain, either to make a puddle for them, or to fix them, as it is called, with water; the object, in both cases, being to supply the plant with abundance of food in its new situation. Care is taken, also, to make the roots firm in the soil, and to let the earth penetrate through all their interstices. To attain these ends, one gardener generally holds the tree and gently shakes it, while another is shovelling in the earth among its roots; but this mode has the disadvantage of sometimes occasioning the roots to become matted. When the tree is to be fixed with water, after a little earth has been shovelled in over the roots, water is applied by pouring it from a watering-pot, held as high as a man can raise it; the watering-pot used being large, and with a wide spout, the rose of which must be taken off. More earth is then shovelled in, and water applied again. This mode of planting has the great advantage of rendering the tree firm, without staking or treading the earth down round it, as is usually done. Other gardeners spread the roots out carefully at the bottom of the hole or pit made to receive them, and then fill in the earth. In all cases, the ground is either made firm with water, or trodden down or beaten flat with the spade after planting, so as to fix the roots firmly in the soil, for the same reasons as nearly a similar plan is adopted in sowing seeds. Newly transplanted trees are frequently staked, but this is not essential if the roots are made firm, and indeed the tree is generally found to do best when the head is left at liberty to be gently agitated by the wind.
It is a great point, in all cases of transplanting, to preserve the epidermis or cellular integument of the fibrous roots and spongioles in a flexible state; and for this reason, the greatest care is taken to keep them moist. This is the end in view in puddling or fixing by water in transplanting; and many planters always dip the roots of trees and shrubs in water before replanting. When a tree or shrub is taken up that is to be conveyed any distance, the roots should be wrapped up as soon as it is taken out of the ground, in wet moss, and covered with bast matting; and where moss cannot be procured, they should be dipped in very wet mud, and then matted up. Cabbage-plants are frequently preserved in this manner; and are conveyed, without any other covering to their roots than a cake of mud, to a considerable distance. In all cases where plants are taken up long before they are replanted, their roots should be kept moist by opening a trench, and laying the plants along it, and then covering their roots with earth. This, gardeners call, laying plants in by the heels. Where this cannot be done, and the plants are kept long out of the ground, their roots should be examined, and moistened from time to time; and before replanting they should be laid in water for some hours, and afterwards carefully examined, and the withered and decayed parts cut off.
In removing large trees, care is taken to prepare the roots by cutting a trench round the tree for a year or two before removal, and pruning off all the roots that project into it. This is to answer the same purpose as transplanting young trees in a nursery; while the bad effects of contracting the range of the roots is counteracted, by filling the trench with rich fresh earth. The removal is also conducted with much care; and either a large ball of earth is removed with the tree, or the roots are kept moist, and spread out carefully, at full length, when the tree is replanted. Some planters, before removing trees, mark which side stood to the south, in order to replant them with the same side turned towards the sun; and this is sometimes done with young trees from a nursery. The reason is, that the tree having generally largest branches, and being always most flourishing on the side exposed to the sun; it is thought that its vegetation might be checked, were a different side presented to that luminary, by the efforts it must make to accommodate itself to its new situation. On the other hand, however, it may be urged that changing the position of the plant, particularly while it is young, will be beneficial in preventing it from taking any particular bent, and in promoting the equal distribution of sap through all the branches.
Watering is a most essential branch of culture. It has been already fully explained that the seed cannot vegetate, and the plant cannot grow without water. Carbon, and all the other substances that form the food of plants, must be dissolved in water to enable the spongioles to take them up; and the spongioles themselves, unless they be kept moist, will soon lose their power of absorption. Nothing indeed can be more evident, even to a common observer, than the necessity that plants feel for water; if a mimulus or a pelargonium in a pot, for example, hang its head and droop its leaves, what an extraordinary and rapid effect is produced by giving it water! In an almost incredibly short time its leaves become firm, and its stem erect; and the plant is not only preserved from death, but restored to full health and beauty.
Watering appears an extremely simple operation, yet nevertheless there are several points relating to it that it is necessary to attend to. One of these is, never to saturate the soil. Water, to be in the best state for being taken up by the plants, should be kept in detached globules by the admixture of air; and it should be only slightly impregnated with nourishing matter from decaying animal or vegetable substances: for, as already observed, when fully saturated with nourishment, it becomes unfit for the food of plants. Nothing can be more admirably and wonderfully adapted for supplying plants properly with water than rain. In falling through the atmosphere, it is thoroughly mixed with the air; and in sinking into the soil it becomes slightly impregnated with nutritious qualities, which it is thus enabled to convey, in the most beneficial manner, to the plants.
It is a very common mistake, in watering, to pour the water down close to the stem of the plant. This is injurious in every respect. Water, when poured profusely on the collar of the plant, which is the point of junction between the root and the stem, is likely to rot, or otherwise seriously injure that vital part; while the spongioles, which alone can absorb the water, so as to benefit the plant, being at the extremity of the roots, are always as far removed from the stem as the nature of the plant will allow. Thus, the distance from the stem at which water should be given varies in different plants. In those that have tap-roots, such as the carrot, and many other culinary vegetables, the lateral fibrous roots are short, and the spongioles are comparatively near the stem; but in trees, and most plants having spreading roots, the spongioles are generally as far distant from the stem as the extremity of the branches; and the water, to be efficacious, should be given there.
The quantity of water to be given varies, not only according to the nature of the plant, but to the state of its growth. In spring, when the sap first begins to be in motion, and the young plant is every day unfolding fresh leaves or blossoms, it requires abundance of water; as it does when in flower, or when the fruit is swelling. In autumn, on the contrary, when the fruit is ripening, and in winter, when the plant is in a state of perfect rest, very little water is necessary, and much is positively injurious, as being likely either to excite a morbid and unnatural action in the vessels, or even to bring on rottenness and decay. Water is necessary for seeds to induce them to germinate; but much of it is very injurious to young plants when they first come up, as it unsettles their roots, and almost washes them away. The roots, also, are at first too weak to imbibe water; and the plants feed on the nourishment contained in the cotyledons of the seeds. It is when the second pair of leaves has opened that water is required, though it should at first be given sparingly. When the plant begins to grow vigorously, it requires more food; and if it be then kept too short of nourishment, it becomes stunted in its growth. The quantity of water requisite also depends on the kind of leaves that the plant unfolds. A plant with large broad leaves, like the tobacco, requires twice as much water as a plant with small pinnate leaves, like an acacia. Plants exposed to a strong light, also, require more than plants grown in the shade.
The time for watering plants varies according to the season. In spring and autumn it is best to water plants in the morning. But in summer, the usual time is the evening; while in winter, the very little that is required, should be given in the middle of the day. Many persons object to watering their plants when the sun is upon them; but this is not at all injurious, so long as the water is not too cold, and is only given to the roots. Watering the leaves when the sun is upon them will make them blister, and become covered with pale brown spots wherever the water has fallen. It is much better to water plants during sunshine, than to suffer them to become too dry; as when the spongioles are once withered, no art can restore them. When plants have been suffered to become too dry, the ground should be loosened before watering it; and water should be given a little at a time, and frequently, till the plant appears to have recovered its vigour. A great deal of the good produced by watering depends on the state of the ground; as when the ground is hard and compact, it is very possible to throw a great quantity of water upon it without doing any service to the plants.
The kind of water used should also be considered. The best is pond-water, as it is always mixed with air, and is, moreover, generally impregnated with decayed animal and vegetable matter; and the worst is clear spring-water, as it is always cold, and is seldom impregnated with air, or with anything but some mineral substance, which, so far from doing good, is positively injurious to the plants. Rain-water collected in open cisterns, and river-water, are both very suitable; and when only spring-water can be obtained, it should be exposed for some time to the air before using it. It is always advisable to have the water at least as warm as the plants to be watered; and for this reason the water to be used in hot-houses and green-houses, is generally kept in an open vessel in the house some hours before using. Watering with warm water is very efficacious in forwarding the flowering of plants. This was one of the things that was most repugnant to my prejudices in the course of my instruction in the art of gardening; and when Mr. Loudon had some nearly boiling hot-water poured on some boxes of hyacinths that I was very anxious to have brought forward, I could scarcely refrain from crying out when I saw the steam rising up from the earth. The hyacinths, however, so far from being injured, flowered splendidly; though such is the force of prejudice, that I could never see the little tin vessel containing the heated water carried out to them without a shudder. The effect of hot-water, not heated to above 200°, in forwarding bulbs is astonishing; but it must be observed that it should never be poured on the bulbs, or on the leaves, but on the earth near the rim of the pot. Hot water is also very efficacious in softening seeds with hard coverings when soaked in it; and some of the seeds of the New Holland acacias will not vegetate in this country till they have been actually boiled.