IT is very customary with many horticultural magazines, to sum up at the end of the season all the improvements which may have been made in gardening during the preceding year. This enables us to see at a glance how much we have progressed, and how far we have left our forefathers behind. Still it must have occurred to many readers of these summaries, that our progress must have been exceedingly slow if all we have been learned to avoid or improve has been noticed in these retrospective sketches. But the fact is, we have advanced faster than our own journals have given us, credit for. Ideas that are really! sound and valuable creep about amongst gardeners like ivy over old ruins, till, once well established, no one knows when or by whom it was planted, or how they originated.

I was strongly reminded of this by reading in an old "Gardener's Calendar" the following advice: " Should dry weather prevail, apply frequent waterings to all newly transplanted trees and shrubs.' I venture to say, that there are very few of our many intelligent gardeners of the present day, who would give such advice; and yet it seems so reasonable that when a plant is likely to wilt, it must require water, that we cannot wonder that the practice still extensively prevails.

It is, therefore, a perfectly natural and legitimate enquiry, that, " If we must not water plants under such circumstances, what must we do to save them ?" The answer will be best understood by being given in detail.

That a plant must have a certain amount of moisture to enable it to live, is well known to every one; and that this moisture must be absorbed through the instrumentality of the fibres, or small rootlets, is a no less widely disseminated fact. When a tree is "well established,' that is, has been growing for some time in a given situation, the rootlets pierce the soil, so that they are in a manner encased by it. In this position how easy it is for them to draw in their required supplies of water. The communication between them and the soil is unbroken, and moisture passes from one to the other by a process nearly akin to capillary attraction. How important then that soil thrown in around the roots at transplanting should be finely pulverized, and that every means should be taken to induce it to enter every "hole and corner." But with the greatest possible care, this can never be done to a perfect degree. The soil will still have an opportunity to sink; that is, will be filled with large air spaces; and whatever roots may be in these cavities, or air spaces, will either get dried up or injured.

It is a first-rate plan, and one which, in critical cases, I have often employed to advantage, to fill the hole intended for the tree with water, throwing in soil enough to make it of the consistency of thin mortar, into which the tree is put, and the remaining soil drawn in without tramping or pressure of any kind. A tree so planted will never require watering afterwards; but it will require other treatment, which will he yet noticed before the end of this chapter.

Surface water should never be applied to a transplanted tree in the manner usually given, for the following reasons : Every one knows that there are certain substances, which do not absorb heat readily, and which are termed good non-conductors; and others which are soon heated, or conductors. Wood is a tolerably good nonconductor, because it will not become as readily heated as iron; while a brick is a better conductor of heat than clay or other soil, because it sooner becomes warmed through. A large clod of earth, also, becomes heated through in much quicker time, than the same bulk of soil would have done in a well pulverized state. This absorption of heat would not, perhaps, be of so much consequence to the plant, were it not for. the increased impetus it gives to evaporation. A large clod of soil not only soon heats through, but soon dries through, - it is a better conductor than pulverized soil.

It is obvious, then, that a soil is in a good condition to retain moisture about the roots of newly transplanted trees, when it is as far removed from a clotty condition as possible. But water, when frequently and forcibly applied to the surface, tends to harden it, and renders it liable to "bake" by a very little sun, therefore, surface watering should, if possible, be avoided; as, indeed, should every thing liable to produce this effect on soils.

The question now occurs, that if a tree has not been watered at transplanting in the manner above described; and if it is evidently suffering, or likely to suffer, for want of moisture, how is it to be applied, except through the surface ? The mode is this : Draw away the soil from around the stem of the tree with a spade or hoe, until the roots are nearly reached, and in such manner as to form a basin around it; fill in water to the brim. An hour or so afterwards, when the water has soaked thoroughly away, draw back the dry soil forming the brim of the basin to its former position as lightly, and without pressure, as possible. It is all the water it will require that season, if properly performed.

And now that we have seen our trees well planted, and those that need it afterwards well watered, how shall we proceed to aid the soil in retaining the moisture supplied to it? Simply by keeping the surface well pulverized, and in the best condition of a non-conductor that we can bring it into; but it is necessary not to mistake what pulverization means. Stirring, or "loosening up" a soil, is not pulverizing it, though often supposed to be. It is, however, the first step towards it. In farming, the plough stirs up the soil; the roller, or harrow, pulverizes. The heo and the spade are the gardener's plough; his feet form his roller, or clod crusher. The operations of ploughing and rolling, and of loosening and pressing, in gardening should always go together; and, in relation to tree planting, whenever a soil is getting hard, or in a "caky" condition, it should not only be hoed or stirred up, but as soon as the loosened soil has become a little dry, it should be pressed with the feet, and crushed to atoms.

This is the whole secret of the business. Get the soil once well encased around the roots, - once well watered, - and all that is necessary afterwards is to keep the surface soil well pulverized, that is, its little atoms well divided, in perfect dust if you will; and there will seldom be a failure, if the tree be healthy otherwise.

I do not imagine I am offering any thing new in this article. The facs are well known to practical gardeners; but I presume that amongst the thousands of readers of the Horticulturist, there are many novices and amateurs to whom the hints may be acceptable.