The Nursery-Book: a Complete Guide to the Multiplication and Pollination of Plants

CHAPTER VII.. Pollination 286-298

Pollination 286-298 General Requirements 287 Methods 291 Crossing of Flowerless Plants 297

NURSERY.--An establishment for the rearing of plants. In America the word is commonly used in connection with the propagation of woody plants only, as fruit-trees and ornamental trees and shrubs. This is erroneous. The word properly includes the propagation of all plants by whatever means, and in this sense it is used in this book.

Tabular Statement of the Ways in which Plants are Propagated.

A. By Seeds.--Seedage.

{ { { Root-tips. { { { Runners. { { 1. By { Layers proper: { { undetached { Simple. { { parts.-- { Serpentine. { { Layerage. { Mound. { { { Pot or Chinese. { { { I. On their { { 1. By undivided parts.-- { own roots. { { Separation (Bulbs, corms, { { { bulbels, bulblets, { { { bulb-scales, tubers, etc). { { { { { 2. By detached { { Division. { { parts. { 2. By divided { Cuttings { { { parts.-- { proper: { { { Cuttage. { Of tubers. B. { { { { Of roots. By Buds. { { { { Of stems. { { { { Of leaves. { { { { I. Budding: Shield, flute, { { { veneer, ring, annular, { { { whistle or tubular. { { { { { { II. Grafting: { { { Whip. { II. On roots { { Saddle. { of other { 1. By detached { Splice. { plants.-- { scions. { Veneer. { Graftage. { { Cleft. { { { Bark. { { { Herbaceous. { { { Seed. { { { Double. { { { Cutting. { { 2. By undetached scions.--Inarching.

CHAPTER I.. Seedage.

SEEDAGE.

=Seedage.=--The process or operation of propagating by seeds or spores, or the state or condition of being propagated by seeds or spores.

There are three external requisites to the germination of seeds--moisture, free oxygen, and a definite temperature. These requisites are demanded in different degrees and proportions by seeds of different species, or even by seeds of the same species when differing widely in age or degree of maturity. The supply of oxygen usually regulates itself. It is only necessary that the seeds shall not be planted too deep, that the soil is porous and not overloaded with water. Moisture and temperature, however, must be carefully regulated.

=Regulation of Moisture.=--Moisture is the most important factor in seedage. It is usually applied to the seeds by means of soil or some similar medium, as moss or cocoanut fiber. Fresh and vigorous seeds endure heavy waterings, but old and poor seeds must be treated sparingly. If there is reason to suspect that the seeds are weak, water should not be applied to them directly. A favorite method of handling them is to sow them in a pot of loose and sandy loam which is set inside a larger pot, the intermediate space being filled with moss, to which, alone, the water is applied. This device is illustrated in Fig. 1. The water soaks through the walls of the inner pot and is supplied gradually and constantly to the soil. Even in this case it is necessary to prevent soaking the moss too thoroughly, especially with very weak seeds. When many pots are required, they may be simply plunged in moss with the same effect. The soil should be simply very slightly moist, never wet. Moisture is sometimes supplied by setting the seed-pot in a shallow saucer of water, or it may be sufficient to simply place it in the humid atmosphere of a propagating-box. Large seeds may be laid upon the surface of the soil in a half-filled pot, covered with thin muslin, and then covered with loose and damp loam. Every day the pot is inverted, the covering taken off and fresh soil is added. A modification of this plan for small seeds can be made by placing the seeds between two layers of thin muslin and inserting them in damp loam, which is frequently renewed to avoid the extremes which would result from watering or from allowing the soil to become dry. In these last operations, no water is applied to the seeds and they constitute one of the most satisfactory methods of dealing with seeds of low vitality. They are essentially the methods long ago used by Knight, who laid such seeds between two sods cut from an old and dry pasture.

Even sound and strong seeds should be watered with care. Drenchings usually weaken or destroy them. The earth should be kept simply damp. To insure comparative dryness in in-door culture, some loose material, as pieces of broken pots or clinkers, should be placed in the bottom of the pot or box to afford drainage. It should be borne in mind, however, that the seed bed should be approximately equally moist throughout its depth. The waterings should therefore be copious enough to moisten the soil throughout. A wet or moist surface over a dry substratum should always be avoided. Error is common here. It is usually best to apply water with a watering-pot, as watering with a hose is apt to wash out the seeds and to pack the soil, and the quantity of water is not so easily regulated.

At first thought, it would appear that the apparently good results following soaking of seeds in many cases, are a contradiction of these statements that seeds may be over-watered. But soaking is usually beneficial only when practiced for a comparatively short time. It is not good practice to soak delicate seeds before sowing, and it is of doubtful utility in most other cases, unless it is necessary to soften the integuments of hard-shelled species, as discussed on page 17. The gain in rapidity of germination following soaked, as compared with dry seeds, is really fictitious, inasmuch as germination actually begins in the soaked seeds before the dry samples are sown. The soaked seeds are sown in water rather than in soil, and as conditions are more uniform there, a gain apparently due to soaking may result. In the case of strong seeds which must be planted out-doors in cold or uncongenial soil, a preliminary soaking of from 12 to 24 hours may be beneficial, as it lessens the period which the seeds would otherwise pass in untoward conditions. But soaked seeds, unless of very hardy species, should never be sown out-doors until the soil has become rather dry and warm.

To prevent too rapid drying out, the soil should be firmly pressed about the seeds. The pot or box should be given a shady place, or some covering may be applied to check evaporation. A pane of glass is often placed over the box, being tilted a little at intervals to allow of ventilation and to prevent the soil from becoming soggy or "sour." A seed-case, with a glass cover, as shown in Fig. 2, is neat and handy in the treatment of small seeds. A thin covering of fine moss is sometimes given, or a newspaper may be thrown over the soil.

In out-door culture, only a naturally dry and well-drained soil should be chosen for all ordinary seeds, especially for such as are sown in the fall or remain in the ground a long time before germinating. Soils which contain a liberal amount of sand or gravel are especially valuable for this purpose.

To prevent drying in out-door culture, it is important that the earth be well firmed over the seeds. Walking on the row, placing one foot directly ahead of the other, is usually the most expeditious and satisfactory operation, at least with large seeds. Or the earth may be firmed with a hoe or the back of a spade, or a board may be placed upon the row and then be thoroughly settled by walking over it. In the sowing of celery and other small and slow seeds, it is a frequent practice to leave the board on the row until the seeds appear in order to hold the moisture. This is a doubtful expedient, however, for the young plants are apt to be quickly dispatched by the sun when the board is removed. If the board is employed, it should be raised an inch or two from the ground as soon as the plants begin to appear. But the shade of the board is too dense and plants do not grow stocky under it. It is better to use brush or lath screens if protection is desired; or fine litter, if free from weed seeds, may be used. In most cases, however, screens will not be needed by celery and similar seeds if the ground is in the proper condition and is well firmed at planting time. It is always advisable, nevertheless, to place the beds for slow and small seeds where they can be watered occasionally.

There are many kinds of screens in use to prevent the drying out of small seeds in out-door seedage and to protect the young seedlings. These are used also in the shading of cuttings. The common lath screen (Fig. 3) is the most useful for general purposes. It is simply a square frame made from common laths laid at right angles in a double series. The interstices between the laths are equal in width to the laths themselves. These screens are laid horizontally upon a light frame-work a few inches above the seeds. The passage of the sun constantly moves the shadows over the bed, and sufficient shade is afforded while thorough ventilation is allowed. This and all other elevated screens are useful in shading and protecting the young plants as well, but when used for this purpose they are usually raised a greater distance above the beds. A brush screen consisting of a low frame covered with boughs, is often used, as shown in Fig. 4. This is cheaper than the lath screens, and is equally as good for most purposes. The brush is often laid directly upon the ground, especially in large beds. This answers the purpose of shading, but it does not allow of weeding and it must be taken off soon after the seeds germinate, or slender plants will be injured in its removal. Brush screens are sometimes raised three or four feet to allow of weeding. A screen for frames is shown in Fig. 5. It is a simple covering of muslin stretched over the top and sides of a rough frame-work. The cloth is usually omitted from the front side. This style of screens is much used by nurserymen, especially for cutting beds. Whitewashing the sashes also affords good shading. A more elaborate and permanent screen is shown in Fig. 6. It is built of slats, usually 3-inch stuff. This shed screen is oftenest used for the protection of tender plants, but it affords an exceedingly useful and convenient place for the storage of pots and boxes of slow-germinating seeds.

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