To a very small extent garden vegetables get their food from the air. The amount obtained in this way however, is so infinitesimal that from the practical standpoint it need not be considered at all. Practically speaking, your vegetables must get all their food from the garden soil.
This important garden fact may seem self-evident, but, if one may judge by their practice, amateur gardeners very frequently fail to realize it. The professional gardener must come to realize it for the simple reason that if he does not he will go out of business. Without an abundant supply of suitable food it is just as impossible to grow good vegetables as it would be to train a winning football team on a diet of soda pop and angel cake. Without plenty of plant food, all the care, coddling, coaxing, cultivating, spraying and worrying you may give will avail little. The soil must be rich or the garden will be poor.
Plant food is of as many kinds, or, more accurately speaking, in as many forms, as is food for human beings. But the first distinction to make in plant foods is that between available and non-available foods--that is, between foods which it is possible for the plant to use, and those which must undergo a change of some sort before the plant can take them up, assimilate them, and turn them into a healthy growth of foliage, fruit or root. It is just as readily possible for a plant to starve in a soil abounding in plant food, if that food is not available, as it would be for you to go unnourished in the midst of soups and tender meats if the latter were frozen solid.
Plants take all their nourishment in the form of soups, and very weak ones at that. Plant food to be available must be soluble to the action of the feeding root tubes; and unless it is available it might, as far as the present benefiting of your garden is concerned, just as well not be there at all. Plants take up their food through innumerable and microscopic feeding rootlets, which possess the power of absorbing moisture, and furnishing it, distributed by the plant juices, or sap, to stem, branch, leaf, flower and fruit. There is one startling fact which may help to fix these things in your memory: it takes from 300 to 500 pounds of water to furnish food for the building of one pound of dry plant matter. You can see why plant food is not of much use unless it is available; and it is not available unless it is soluble.
THE THEORY OF MANURING
The food of plants consists of chemical elements, or rather, of numerous substances which contain these elements in greater or less degrees. There is not room here to go into the interesting science of this matter. It is evident, however, as we have already seen that the plants must get their food from the soil, that there are but two sources for such food: it must either be in the soil already, or we must put it there. The practice of adding plant food to the soil is what is called manuring.
The only three of the chemical elements mentioned which we need consider are: nitrogen, phosphoric acid, and potassium. The average soil contains large amounts of all three, but they are for the most part in forms which are not available and, therefore, to that extent, may be at once dismissed from our consideration. (The non-available plant foods already in the soil may be released or made available to some extent by cultivation. See Chapter VII.) In practically every soil that has been cultivated and cropped, in long-settled districts, the amounts of nitrogen, phosphoric acid and potassium which are immediately available will be too meager to produce a good crop of vegetables. It becomes absolutely necessary then, if one would have a really successful garden, no matter how small it is, to add plant foods to the soil abundantly. When you realize, (1) that the number of plant foods containing the three essential elements is almost unlimited, (2) that each contains them in different proportions and in differing degrees of availability, (3) that the amount of the available elements already in the soil varies greatly and is practically undeterminable, and (4) that different plants, and even different varieties of the same plant, use these elements in widely differing proportions; then you begin to understand what a complex matter this question of manuring is and why it is so much discussed and so little understood. What a labyrinth it offers for any writer--to say nothing of the reader--to go astray in!
I have tried to present this matter clearly. If I have succeeded it may have been only to make the reader hopelessly discouraged of ever getting at anything definite in the question of enriching the soil. In that case my advice would be that, for the time being, he forget all about it. Fortunately, in the question of manuring, a little knowledge is not often a dangerous thing. Fortunately, too, your plants do not insist that you solve the food problem for them. Set a full table and they will help themselves and take the right dishes. The only thing to worry about is that of the three important foods mentioned (nitrogen, phosphoric acid and potassium) there will not be enough: for it has been proved that when any one of these is exhausted the plant practically stops growth; it will not continue to "fill up" on the other two. Of course there is such a thing as going to extremes and wasting plant foods, even if it does not, as a rule, hurt the plants. If, however, the fertilizers and manures described in the following sections are applied as directed, and as mentioned in Chapter VII., good results will be certain, provided the seed, cultivation and season are right.
The terms "manure" and "fertilizer" are used somewhat ambiguously and interchangeably. Using the former term in a broad sense--as meaning any substance containing available plant food applied to the soil, we may say that manure is of two kinds: organic, such as stable manure, or decayed vegetable matter; and inorganic, such as potassium salts, phosphatic rock and commercial mixed fertilizers. In a general way the term "fertilizer" applies to these inorganic manures, and I shall use it in this sense through the following text.
Between the organic manures, or "natural" manures as they are often called, and fertilizers there is a very important difference which should never be lost sight of. In theory, and as a chemical fact too, a bag of fertilizer may contain twice the available plant food of a ton of well rotted manure; but out of a hundred practical gardeners ninetynine--and probably one more--would prefer the manure. There is a reason why--two reasons, even if not one of the hundred gardeners could give them to you. First, natural manures have a decided physical effect upon most soils (altogether aside from the plant food they contain); and second, plants seem to have a preference as to the form in which their food elements are served to them. Fertilizers, on the other hand, are valuable only for the plant food they contain, and sometimes have a bad effect upon the physical condition of the soil.
When it comes right down to the practical question of what to put on your garden patch to grow big crops, nothing has yet been discovered that is better than the old reliable stand-by--well rotted, thoroughly fined stable or barnyard manure. Heed those adjectives! We have already seen that plant food which is not available might as well be, for our immediate purposes, at the North Pole. The plant food in "green" or fresh manure is not available, and does not become so until it is released by the decay of the organic matters therein. Now the time possible for growing a crop of garden vegetables is limited; in many instances it is only sixty to ninety days. The plants want their food ready at once; there is no time to be lost waiting for manure to rot in the soil. That is a slow process--especially so in clayey or heavy soils. So on your garden use only manure that is well rotted and broken up. On the other hand, see that it has not "fire-fanged" or burned out, as horse manure, if piled by itself and left, is very sure to do. If you keep any animals of your own, see that the various sorts of manure --excepting poultry manure, which is so rich that it is a good plan to keep it for special purposes--are mixed together and kept in a compact, built-up square heap, not a loose pyramidal pile. Keep it under cover and where it cannot wash out. The pile should be turned from bottom to top and outside in and rebuilt, treading down firmly in the process, every month or two--applying water, but not soaking, if it has dried out in the meantime. Such manure will be worth two or three times as much, for garden purposes, as that left to burn or remain in frozen lumps. If you have to buy all your manure, get that which has been properly kept; and if you are not familiar with the condition in which it should be, get a disinterested gardener or farmer to select it for you. When possible, it will pay you to procure manure several months before you want to use it and work it over as suggested above. In buying manure keep in mind not what animals made it, but what food was fed--that is the important thing. For instance, the manure from highly-fed livery horses may be, weight for weight, worth three to five times that from cattle wintered over on poor hay, straw and a few roots.
There are other organic manures which it is sometimes possible for one to procure, such as refuse brewery hops, fish scraps and sewage, but they are as a rule out of the reach of, or objectionable for, the purposes of the home gardener.
There are, however, numerous things constantly going to waste about the small place, which should be converted into manure. Fallen leaves, grass clippings, vegetable tops and roots, green weeds, garbage, house slops, dish water, chip dirt from the wood-pile, shavings--any thing that will rot away, should go into the compost heap. These should be saved, under cover if possible, in a compact heap and kept moist (never soaked) to help decomposition. To start the heap, gather up every available substance and make it into a pile with a few wheelbarrows full, of fresh horse manure, treading the whole down firmly. Fermentation and decomposition will be quickly started. The heap should occasionally be forked over and restacked. Light dressings of lime, mixed in at such times, will aid thorough decomposition.
Wood ashes form another valuable manure which should be carefully saved. Beside the plant food contained, they have a most excellent effect upon the mechanical condition of almost every soil. Ashes should not be put in the compost heap, because there are special uses for them, such as dusting on squash or melon vines, or using on the onion bed, which makes it desirable to keep them separate. Wood ashes may frequently be bought for fifty cents a barrel, and at this price a few barrels for the home garden will be a good investment.
Coal ashes contain practically no available plant food, but are well worth saving to use on stiff soils, for paths, etc.
VALUE OF GREEN MANURING
Another source of organic manures, altogether too little appreciated,
is what is termed "green manuring"--the plowing under of growing crops to enrich the land. Even in the home garden this system should be taken advantage of whenever possible. In farm practice, clover is the most valuable crop to use for this purpose, but on account of the length of time necessary to grow it, it is useful for the vegetable garden only when there is sufficient room to have clover growing on, say, one half-acre plot, while the garden occupies, for two years, another half-acre; and then changing the two about. This system will give an ideal garden soil, especially where it is necessary to rely for the most part upon chemical fertilizers.
There are, however, four crops valuable for green-manuring the garden, even where the same spot must be occupied year after year: rye, field corn, field peas (or cow peas in the south) and crimson clover. After the first of September, sow every foot of garden ground cleared of its last crop, with winter rye. Sow all ground cleared during August with crimson clover and buckwheat, and mulch the clover with rough manure after the buckwheat dies down. Sow field peas or corn on any spots that would otherwise remain unoccupied six weeks or more. All these are sown broadcast, on a freshly raked surface. Such a system will save a very large amount of plant food which otherwise would be lost, will convert unavailable plant food into available forms while you wait for the next crop, and add humus to the soil--concerning the importance of which see Chapter VII.
I am half tempted to omit entirely any discussion of chemical fertilizers: to give a list of them, tell how to apply them, and let the why and wherefore go. It is, however, such an important subject, and the home gardener will so frequently have to rely almost entirely upon their use, that probably it will be best to explain the subject as thoroughly as I can do it in very limited space. I shall try to give the theory of scientific chemical manuring in one paragraph.
We have already seen that the soil contains within itself some available plant food. We can determine by chemical analysis the exact amounts of the various plant foods--nitrogen, phosphoric acid, potassium, etc.--which a crop of any vegetable will remove from the soil. The idea in scientific chemical manuring is to add to the available plant foods already in the soil just enough more to make the resulting amounts equal to the quantities of the various elements used by the crop grown. In other words:
Available plant food elements in the soil, plus available chemical food elements supplied in fertilizers equals amounts of food elements in matured crop.
That was the theory--a very pretty and profound one! The discoverers of it imagined that all agriculture would be revolutionized; all farm and garden practice reduced to an exact science; all older theories of husbandry and tillage thrown by the heels together upon the scrap heap of outworn things. Science was to solve at one fell swoop all the age-old problems of agriculture. And the whole thing was all right in every way but one--it didn't work. The unwelcome and obdurate fact remained that a certain number of pounds of nitrogen, phosphoric acid and potassium--about thirty-three--in a ton of good manure would grow bigger crops than would the same number of pounds of the same elements in a bag of chemical fertilizer.
Nevertheless this theory, while it failed as the basis of an exact agricultural science, has been developed into an invaluable guide for using all manures, and especially concentrated chemical manures. And the above facts, if I have presented them clearly, will assist the home gardener in solving the fertilizer problems which he is sure to encounter.
What are termed the raw materials from which the universally known "mixed fertilizers" are made up, are organic or inorganic substances which contain nitrogen, phosphoric acid or potassium in fairly definite amounts.
Some of these can be used to advantage by themselves. Those practical for use by the home gardener, I mention. The special uses to which they are adapted will be mentioned in Part Two, under the vegetables for which they are valuable.
GROUND BONE is rich in phosphate and lasts a long time; what is called "raw bone" is the best "Bone dust" or "bone flour" is finely pulverized; it will produce quick results, but does not last as long as the coarser forms.
COTTON-SEED MEAL is one of the best nitrogenous fertilizers for garden crops. It is safer than nitrate of soda in the hands of the inexperienced gardener, and decays very quickly in the soil.
NITRATE OF SODA, when properly handled, frequently produces wonderful results in the garden, particularly upon quick-growing crops. It is the richest in nitrogen of any chemical generally used, and a great stimulant to plant growth. When used alone it is safest to mix with an equal bulk of light dirt or some other filler. If applied pure, be sure to observe the following rules or you may burn your plants: (1) Pulverize all lumps; (2) see that none of it lodges upon the foliage;
(3) never apply when there is moisture upon the plants; (4) apply in many small doses--say 10 to 20 pounds at a time for 50 x 100 feet of garden. It should be put on so sparingly as to be barely visible; but its presence will soon be denoted by the moist spot, looking like a big rain drop, which each particle of it makes in the dry soil. Nitrate of soda may also be used safely in solution, at the rate of 1 pound to 12 gallons of water. I describe its use thus at length because I consider it the most valuable single chemical which the gardener has at command.
MURIATE and SULPHATE OF potassium are also used by themselves as sources of potassium, but as a general thing it will be best to use them in combination with other chemicals as described under "Home Mixing."
LIME will be of benefit to most soils. It acts largely as an indirect fertilizer, helping to release other food elements already in the soil, but in non-available forms. It should be applied once in three to five years, at the rate of 75 to 100 bushels per acre, after plowing, and thoroughly tilled in. Apply as long before planting as possible, or in the fall.
Mixed fertilizers are of innumerable brands, and for sale everywhere. It is little use to pay attention to the claims made for them. Even where the analysis is guaranteed, the ordinary gardener has no way of knowing that the contents of his few bags are what they are labeled. The best you can do, however, is to buy on the basis of analysis, not of price per ton--usually the more you pay per bag, the cheaper you are really buying your actual plant food. Send to the local Cooperative Extension Service in your State and ask for the last bulletin on fertilizer values. It will give a list of the brands sold throughout the State, the retail price per ton, and the actual value of plant foods contained in a ton. Then buy the brand in which you will apparently get the greatest value.
For garden crops the mixed fertilizer you use should contain (about):
Nitrogen, 4 per cent. (Basic formula Phosphoric acid, 8 per cent. = for potassium, 10 per cent. Garden crops)
If applied alone, use at the rate of 1000 to 1500 pounds per acre. If with manure, less, in proportion to the amount of the latter used.
By "basic formula" (see above) is meant one which contains the plant foods in the proportion which all garden crops must have. Particular crops may need additional amounts of one or more of the three elements, in order to attain their maximum growth. Such extra feeding is usually supplied by top dressings, during the season of growth. The extra food beneficial to the different vegetables will be mentioned in the cultural directions in Part Two.
If you look over the local Cooperative Extension Service report mentioned above, you will notice that what are called "home mixtures" almost invariably show a higher value compared to the cost than any regular brand. In some cases the difference is fifty per cent. This means that you can buy the raw chemicals and make up your own mixtures cheaper than you can buy mixed fertilizers. More than that, it means you will have purer mixtures. More than that, it means you will have on hand the materials for giving your crops the special feeding mentioned above. The idea widely prevails, thanks largely to the fertilizer companies, that home mixing cannot be practically done, especially upon a small scale. From both information and personal experience I know the contrary to be the case. With a tight floor or platform, a square-pointed shovel and a coarse wire screen, there is absolutely nothing impractical about it. The important thing is to see that all ingredients are evenly and thoroughly mixed. A scale for weighing will also be a convenience. Further information may be had from the firms which sell raw materials,or from your local Cooperative Extension Service.
The matter of properly applying manure, even on the small garden, is also of importance. An amount of 40-50 whelbarrows full will not be too much; although if fertilizers are used to help out, the manure may be decreased in proportion. If possible, take it from the heap in which it has been rotting, and spread evenly over the soil immediately before plowing. If actively fermenting, it will lose by being exposed to wind and sun. If green, or in cold weather, it may be spread and left until plowing is done. When plowing, it should be completely covered under, or it will give all kinds of trouble in sowing and cultivating.
Fertilizers should be applied, where used to supplement manure or in place of it, at from 500 to 1500 pounds per acre, according to grade and other conditions. It is sown on broadcast, after plowing, care being taken to get it evenly distributed. This may be assured by sowing half while going across the piece, and the other half while going lengthwise of it. When used as a starter, or for top dressings--as mentioned in connection with the basic formula--it may be put in the hill or row at time of planting, or applied on the surface and worked in during the growth of the plants. In either case, especially with highly concentrated chemicals, care must be taken to mix them thoroughly with the soil and to avoid burning the tender roots.
Mulching enriches and protects soil, helping to provide a better growing environment. In your backyard Mulching is one of the simplest and most beneficial practices you can use in the garden. Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be organic--such as grass clippings, straw, bark chips, and similar materials--or inorganic-such as stones, brick chips, and plastic. Both organic and inorganic mulches have numerous benefits. Mulching benefits include:
• protects the soil from erosion
• reduces compaction from the impact of heavy rains
• conserves moisture, reducing the need for frequent waterings
• maintains a more even soil temperature
• prevents weed growth
• keeps fruits and vegetables clean
• keeps feet clean, allowing access to garden even when damp
• provides a "finished" look to the garden
Organic mulches also improve the condition of the soil. As these mulches slowly decompose, they provide organic matter which helps keep the soil loose. This improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil. Organic matter is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms.
Another great thing about mulch--You can find mulch materials in your own yard! Lawn clippings make excellent mulch. They will work wonderfully in the vegetable garden. The fine texture allows them to be spread easily even around small plants. However, grass clippings are becoming scarce because of the increased popularity of mulching lawnmowers that provide many of the same benefits of mulching to lawns. Newspaper, as a mulch, works especially well to control weeds. Leaves are another readily available material to use as mulch. Leaf mold, or the decomposed remains of leaves, gives the forest floor its absorbent spongy structure. Compost makes a wonderful mulch if you have a large supply. Compost not only improves the soil structure but provides an excellent source of plant nutrients. Bark chips and composted bark mulch are available at garden centers. These make a neat finish to the garden bed and will eventually improve the condition of the soil. These may last for one to three years or more depending on the size of the chips or how well composed the bark mulch is. Smaller chips tend to be easier to spread, especially around small plants. Depending on where you live, numerous other materials make excellent mulches. Hay and straw work well in the vegetable garden, although they may harbor weed seeds. Seaweed mulch, ground corn cobs, and pine needles can also be used. Pine needles tend to increase the acidity of the soil so they work best around acid-loving plants such as blueberries.
WHEN TO APPLY MULCH
Time of application depends on what you hope to achieve by mulching. Mulches, by providing an insulating barrier between the soil and the air, moderate the soil temperature. This means that a mulched soil in the summer will be cooler than an adjacent unmulched soil; while in the winter, the mulched soil may not freeze as deeply. However, since mulch acts as an insulating layer, mulched soils tend to warm up more slowly in the spring and cool down more slowly in the fall than unmulched soils. If you are using mulches in your vegetable garden , it is best to apply them after the soil has warmed up in the spring. Cool, wet soils tend to slow seed germination and increase the decay of seeds and seedlings. Mulches used to help moderate winter temperatures can be applied late in the fall after the ground has frozen but before the coldest temperatures arrive. Applying mulches before the ground has frozen may attract rodents looking for a warm over-winter site. Delayed applications of mulch should prevent this problem as, hopefully, the creatures would already have found some other place to nest. Mulches used to protect plants over winter should be loose material such as straw, hay, or pine boughs that will help insulate the plants without compacting under the weight of snow and ice. One of the benefits from winter applications of mulch is the reduction in the freezing and thawing of the soil in the late winter and early spring. These repeated cycles of freezing at night and then thawing in the warmth of the sun cause many small or shallow rooted plants to be heaved out of the soil. This leaves their root systems exposed and results in injury or death. Mulching helps prevent rapid fluctuations in soil temperature and reduces the chances of heaving.
You should begin by asking yourself the following questions.
a. What do I hope to achieve by mulching? Weed control? Moisture retention? Soil improvement? Beautification?
b. How large is the area to be mulched?
c. How much mulch will I need to cover the area? Mulch is measured in cubic feet. As an example, if you have an area 10 feet by 10 feet and you wish to apply 3 inches of mulch, you would need 25 cubic feet. (10' x 10' x .25' = 25 cu. ft.) Next you need to determine what mulch material to use and purchase or accumulate what you need. Mulch can often be purchased bagged
or bulk from garden centers. Bulk may be cheaper if you need large volumes and have a way to haul it. Bagged mulch is often easier to handle, especially for smaller projects. Most bagged mulch comes in 3-cubic feet bags.
Refer to the section on composting for information on how to make your own compost.
Collect leaves in the fall. Chop them up with a lawnmower or shredder. Whole leaves tend to compact if wet or blow away if dry. Chopping will reduce the volume and facilitate composting. Compost leaves over winter. Some studies have indicated that freshly chopped leaves may inhibit the growth of certain crops. Therefore, it may be advisable to compost the leaves over winter before spreading them.
Spread grass clippings immediately to avoid heating and rotting. Use only newspaper text pages (black ink); color dyes may be harmful to soil microflora and fauna if composted and used. Use 3 or 4 sheets together, anchored with grass clippings or other mulch material to prevent them from blowing away.
The amount of mulch to apply will be determined by the mulch material you are using. The general guidelines are:
Do not apply mulch directly in contact with plants. Leave an inch or so of space next to plants to help prevent diseases flourishing from excessive humidity.
Remove weeds before spreading mulch. Bark mulch and wood chips are sometimes used with landscape fabric or plastic. The fabric or plastic is laid on top of the soil and then covered with a layer of bark chips. One caution to this practice: while the plastic or fabric may initially provide additional protection against weeds, as the mulch breaks down,weeds will start to grow in the mulch itself. The barrier between the soil and the mulch also prevents any improvement in the soil condition and makes planting additional plants more difficult.
A great source for mulch may be your local community. They may have wood chips from the removal of street trees that are available free to residents.
This chapter is longer than I wanted to make it, but the problem of how best to enrich the soil is the most difficult one in the whole business of gardening, and the degree of your success in growing vegetables will be measured pretty much by the extent to which you master it. You cannot do it at one reading. Re-read this chapter, and when you understand the several subjects mentioned, in the brief way which limited space made necessary, pursue them farther in one of the several comprehensive books on the subject. It will well repay all the time you spend upon it. Because, from necessity, there has been so much of theory mixed up with the practical in this chapter, I shall very briefly recapitulate the directions for just what to do, in order that the subject of manuring may be left upon the same practical basis governing the rest of the book.
To make your garden rich enough to grow big crops, buy the most thoroughly worked over and decomposed manure you can find. If it is from grain-fed animals, and if pigs have run on it, it will be better yet. If possible, buy enough to put on at the rate of about twenty cords to the acre; if not, supplement the manure, which should be plowed under, with 500 to 1500 pounds of high-grade mixed fertilizer (analyzing nitrogen four per cent., phosphoric acid eight per cent., potassium ten per cent.)--the quantity in proportion to the amount of manure used, and spread on broadcast after plowing and thoroughly tilled in. In addition to this general enrichment of the soil, suitable quantities of nitrate of soda, for nitrogen; bone dust (or acid phosphate), for phosphoric acid; and sulphate of potassium, for potassium, should be bought for later dressings, as suggested in cultural directions for the various crops.
If the instructions in the above paragraph are followed out you may rest assured that your vegetables will not want for plant food and that, if other conditions are favorable, you will have maximum crops.