The following is a summary of the general rules to be observed in manuring and improving soils:—Never to use animal manure and quick-lime together, as the one will destroy the other. To use lime as a manure only in very sandy or peaty soils, or in soils abounding with sulphate of iron. To remember that rotten manure is considered to give solidity; and that unfermented manure, buried in trenching, has a tendency to lighten the soil. To dilute liquid manure from a dunghill with water, before applying it to growing plants; as otherwise, from the quantity of ammonia that it contains it will be apt to burn them. To cover and surround dunghills with earth during the process of fermentation, to absorb the nutritious gases, that would otherwise escape. To remember that the manure of cows and all animals that chew the cud, is cold and suited to a light soil; and that the manure of horses, pigs, and poultry is hot and suited to a firm soil: also that all manure, when well rotten, becomes cold in its nature, and should be treated accordingly. To remember that all mixed soils are more fertile than soils consisting only of one of the three primitive earths, viz. lime, sand, or clay; and never to forget that too much manure is quite as injurious to plants as too little.
Formation of hotbeds.—Though nearly all the kinds of manure which have been enumerated may be used occasionally for hotbeds, the only materials in common use in gardens, are stable manure, dead leaves, and tan. The first of these, which is by far the most general, consists partly of horse-dung, and partly of what gardeners call long litter, that is, straw moistened and discoloured, but not decayed. The manure is generally in this state, when it is purchased, or taken from the stable, for the purpose of making a hot-bed.
The necessary quantity of manure is procured at the rate of one cart load, or from twelve to fifteen large wheel-barrowfuls to every light, as the gardeners call the sashes of the frames, each light being about three feet wide; and this manure is laid in a heap to ferment. The heap should then be covered with earth to receive the gases evolved during fermentation, and earth laid round it to absorb the liquid manure that may drain from it. In about a week the earth may be removed, and the manure turned over with a dung-fork, and well shaken together; this operation being repeated two or three or more times, at intervals of two or three days, till the whole mass is become of one colour, and the straws are sufficiently decomposed to be torn to pieces with the fork.
The size of the hotbed must depend principally on the size of the frame which is to cover it; observing that the bed must be from six inches to a foot wider than the frame every way. The manure must then be spread in layers, each layer being beaten down with the back of the fork, till the bed is about three feet and a half high. The surface of the ground on which the hotbed is built, is generally raised about six inches above the general surface of the garden; and it is advisable to lay some earth round the bottom of the bed, nearly a foot wide, that it may receive the juices of the manure that will drain from the bed. As soon as the bed is made, the frame is put on and the sashes kept quite close, till a steam appears upon the glass, when the bed is considered in a fit state to be covered three or four inches deep with mould; observing, if the bed has settled unequally, to level the surface of the manure before covering it with earth. The seeds to be raised may either be sown in this earth, or in pots to be plunged in it.
The proper average heat for a hotbed intended to raise flower seeds, or to grow cucumbers, is 60°: but melons require a heat of 65° to grow in, and 75° to ripen their fruit. This heat should be taken in a morning, and does not include that of the sun in the middle of the day. When the heat of the bed becomes so great as to be in danger of injuring the plants, the obvious remedy is to give air by raising the glasses; and if this be not sufficient, the general heat of the bed must be lowered by making excavations in the dung from the sides, so as to reach nearly to the middle of the bed, and filling up these excavations with cold dung which has already undergone fermentation, or with leaves, turf, or any other similar material which will receive heat, but not increase it. When the heat of the bed falls down to 48° or lower, it should be raised, by applying on the outside fresh coatings of dung, grass, or leaves, which are called linings.
When hotbeds are made of spent tanner’s bark or decayed leaves, a kind of box or pit must be formed of bricks or boards, or even of layers of turf, or clay, and the tan or leaves filled in so as to make a bed. Where neatness is an object, this kind of bed is preferable to any other; but a common hotbed of stable manure may be made to look neat by thatching the outside with straw, or covering it with bast mats, pegged down to keep them close to the bed.
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.