The soil must furnish the whole foundation of plant life. For centuries those who have grown things have realized the vital importance of having the soil rich or well supplied with plant food; and if this is important in growing plants in the field or flower garden, where each vegetable or flower has from one to several cubic feet of earth in which to grow, how imperative it is to have rich soil in a pot or plant box where each plant may have but a few cubic inches!

But the trouble is not so much in knowing that plants should be given rich soil, as to know how to furnish it. I well remember my first attempt at making soil rich and thinking how I would surprise my grandmother, who worked about her plants in pots every day of her life, and still did not have them as big as they grew in the flower garden. I had seen the hired man put fertilizer on the garden. That was the secret! So I got a wooden box about two-thirds full of mellow garden earth, and filled most of the remaining space with fertilizer, well mixed into the soil, as I had seen him fix it. I remember that my anxiety was not that I get too much fertilizer in the soil, but that I would take so much out of the bag that it would be missed. Great indeed was my chagrin and disappointment, twelve hours after carefully setting out and watering my would-be prize plants, to notice that they had perceptibly turned yellow and wilted. And I certainly had made the soil rich.

So the problem is by no means as simple as might at first be supposed. Not only must sufficient plant food be added to the soil but it must be in certain forms, and neither too much nor too little may be given if the best results are to be attained.

Now it is a fact established beyond all dispute that not only food, but air and water, as well, must be supplied to the roots of growing plants; and this being the case, the mechanical condition of the soil in which the plant is to grow has a great deal to do with its success or failure. It must be what is termed a porous and friable soil—that is, one so light and open that water will drain through it without making it a compact, muddy mass. One of the things I noticed about my special fertilizer soil, mentioned above, was that it settled, after being watered, into a solid mass from which water would not drain and into which air could not penetrate.

It is next to impossible to find a soil just right for house plants, so, as a general thing the only way to get a good soil is to mix it yourself. For this purpose several ingredients are used. If you live in a village or suburb, where the following may be procured, your problem is not a difficult one. Take about equal parts of rotted sod, rotted horse manure and leaf-mould from the woods and mix thoroughly and together, adding from one-sixth to one-third, in bulk, of coarse sand. If a considerable quantity of soil will be required during the year, it will be well to have some place, such as a bin or large barrel, in which to keep a supply of each ingredient. The sod should be cut three or four inches thick, and stacked in layers with the grassy sides together, giving an occasional soaking, if the weather is dry, to hasten rotting. The manure should be decomposed under cover, and turned frequently at first to prevent burning out; or sod and manure can be rotted together, stacking them in alternate layers and forking over two or three times after rotting has begun. The manure furnishes plant food to the compost, the rotted sod "body," the leaf-mould water-absorbing qualities, and the sand, drainage qualities.

If the soil is wanted at once, and no rotted sod is to be had, use good garden loam, preferably from some spot which was under clover-sod the year before. If it is difficult to obtain well-rotted manure, street sweepings may be used as a substitute, and old chip-dirt from under the wood pile, or the bottom of the woodshed if it has a dirt floor, will do in place of leaf-mould. Peat, or thoroughly dried and sweetened muck are also good substitutes for leaf-mould. Finely screened coal ashes may take the place of sand.

If you live in the city, where it is difficult to obtain and to handle the several materials mentioned, the best way is to get your soil ready mixed at the florists, as a bushel will fill numerous pots. If you prefer to mix it yourself, or to add any of the ingredients to the soil you may have, most florists can supply you with light soil, sand, peat or leaf-mould and rotted manure; and sphagnum moss, pots, saucers and other things required for your outfit. If a large supply is wanted, it would probably be cheaper to go to some establishment on the outskirts of the city where things are actually grown, than to depend upon the retail florist nearer at hand.

Potting soil when ready to use should be moist enough to be pressed into a ball by the hand, but never so moist as not to crumble to pieces again readily beneath the finger.

MANURES

Manure of some sort is essential to the growing of plants in pots or boxes, both because of the plant-food it adds to the soil, and because it improves its mechanical condition and sponginess or water-holding quality. Thoroughly rotted horse manure or horse and cow manure mixed is by far the best. Cow manure alone, or pig manure, is lumpy and cold, and hen, sheep, pigeon or other special manures are not safe in the hands of the beginner, as they are one-sided, being especially rich in nitrogen and likely either to burn the plants or to cause too soft and watery growth.

This brings us to the point where it is necessary to say a few words about the theory of manures, for they are not all alike and what would be wise to give a plant under some circumstances under others would be quite wrong, just as you would not think of feeding beefsteak to a baby just recovering from the colic, while it might be a very good thing for a hungry man who was going to saw up your wood-pile.

Plants of all sorts—in pots, in the garden or in a ten-acre lot—require three kinds of food elements: nitrogen, phosphoric acid and potash. These elements may be fed to the plants in various forms; for instance, the nitrogen in hen manure, or in cottonseed meal, or in salts from the nitrate fields of Chile, known as nitrate of soda; the phosphoric acid from bone, or from acid phosphate (a ground rock treated with acid); the potash from wood ashes or from German potash salts (muriate or sulphate of potash). Plants, to do their best, require that all three elements shall be present in sufficient amounts to supply their wants.

It is not necessary, however, to go very deeply into the science of plant foods in order to grow plants successfully. Fortunately, manure rotted as described above, furnishes all three elements in about the right proportions. Cow, sheep, hen and pigeon manure are best used as described later, under "Liquid Manuring."

FERTILIZERS

There are many brands of mixed fertilizers prepared specially for use in the greenhouse or on plants in pots. There is a temptation to use these on account of their convenient compact form, and because they are more agreeable to handle. As a general rule, however, much better results will be obtained by relying on rotted manure.

If you want to use fertilizers at all—and for certain purposes they will be very valuable—I would advise restricting the list to the following pure materials which are not mixed, and which are always uniform; nitrate of soda, cottonseed meal, pure fine ground bone, and wood ashes. (Several of the other chemicals are good, but not so commonly used.)

Ground bone is the most valuable of these. It should be what is known as "fine ground," or bone dust. It induces a strong but firm growth, and can be used safely in the potting soil, supplementing the manure as a source of plant food. From two to three quarts to a bushel of soil is the right amount to use. It should be thoroughly mixed through the soil. It may also be frequently used to advantage as a top dressing on plants that have exhausted the food in their pots, or while developing buds or blooming. Work two or three spoonfuls into the top of the soil.

Nitrate of soda is the next in importance. It is very strong and must be carefully used, the safest way being to use it as a liquid manure, one or two teaspoonsful dissolved in three gallons of water. If first dissolved in a pint of hot water, and then added to the other, it will be more quickly done. Use a pint or so of this solution in watering. The results will often be wonderful.

Cottonseed meal may be safely mixed with the soil, like ground bone, but requires some time in which to rot, before the plant can make use of it.

Wood ashes are also safe, and good to add to the potting soil. They help to make a firm, hard growth, as a result of the potash they furnish. Where plants seem to be making a too rapid, watery growth, wood ashes may be applied to the surface and worked in.

With a soil prepared as directed in the first part of this chapter, there will be very little need for using any other of the fertilizers, until plants have been shifted into their last pots and have filled them with roots. When this stage is reached the use of liquid manures as described later will frequently be beneficial. If, however, a plant for any reason seems backward, or slower in growth than it should be, an application or two of nitrate of soda will often produce results almost marvelous. Be sure, however, that your troubles are not due to some mistake in temperature, ventilation or watering, before you ascribe them to improper or exhausted soil.

Now, having had the patience to find out something about the conditions under which plants ought to succeed, let us proceed to the more interesting work of actually making them grow.