Saturday, February 23, 2008

HOW SOIL WORKS WITH YOUR PLANTS

Essentially the function of the soil in relation to the plants that grow in it is fourfold: It must supply water; it must supply nutrients; it must supply gases (carbon dioxide and oxygen); and it must be firm enough to support the plant securely. The ideal soil is a middle-of-the-road mixture, holding moisture and nutrients while letting excess water drain away to make room for air.
Don't make the mistake of assuming that your garden contains only one type of soil; several different soils can exist in one backyard. Each natural soil is composed of fine rock particles, organic matter, and microorganisms. A good soil is 50 percent solids and 50 percent porous space, which provides room for water, air, and plant roots. The solids are 80 to 90 percent inorganic matter and 10 to 20 percent organic materials. Water and air should each occupy about half of the porous space.
Types of soil
There are four basic types of soil, and the texture of each is determined by the different proportions of various-sized soil particles. These four types of soil are clay, sand, silt, and loam.
Clay soil. A clay soil is composed of particles that are less than 1/3 of an inch (1/200 mm) in diameter. These minute particles pack together more closely than larger particles and have a greater total surface area. Clay soil can hold more water than other soils. It often drains poorly, but drainage can be improved by the addition of organic matter to break up the clay particles. If you try to work with a clay soil when it's wet, you'll compress the particles even more closely; then, when the soil dries, you'll be left with a surface something like baked brick or concrete. Properly managed, however, clay soils can be the most productive of all.
Sandy soil. A sandy soil is made up mostly of particles that are over 1/3175 of an inch (1/20 mm) in diameter. They are much larger than clay particles and irregular in shape, so they don't pack as closely together as clay particles. Because they have less total surface area, these larger particles hold less water than smaller particles and are much more porous.
Sandy soil drains like a sieve, but can be improved by the addition of organic matter, which helps retain moisture and nutrients. Silt soil. In a silt soil the size of the particles is intermediate — between clay and sand. Depending on the size of its particles, a silt soil can act either like a clay soil or like a fine sandy soil. Silt consists of small, gritty particles that can pack down very hard, and it's not very fertile. Silt soil is often found on top of heavy clay, which slows or stops drainage.
Loam. Loam is a mixture of clay, silt, and sand particles. A good garden loam is something to cherish, particularly if it also contains a heavy supply of organic matter. All soil improvement is aimed at achieving a good loam — when you add organic matter or make other improvements to your clay or sandy soil, you're trying to provide the type of loam that lucky gardeners have without all that extra work.
A do-it-yourself test of soil mixture The best way to determine the approximate texture of the soil in your garden is by feeling it with your hands. Try this test: Take a small handful of moist garden soil, and hold some of the sample between your thumb and the first knuckle of your forefinger.
Gradually squeeze the soil out with your thumb to form a ribbon. If you can easily form a ribbon that holds together for more than one inch, you have a very heavy clay soil. If a ribbon forms, but it holds together for only three-quarters of an inch to one inch, your soil is a silty clay loam. If the ribbon forms but breaks into pieces shorter than three-quarters of an inch, you have a silty soil. If a ribbon won't form at all, you have a sandy soil.

IMPROVING YOUR GARDEN SOIL
Unless you're one of the lucky people with a garden full of rich, productive loam, it's probable that you will want to improve your soil in the interests of harvesting a bigger and better crop of vegetables at the end of your growing season. When you're planning your soil-improvement program you have to take two issues into account: the texture of the soil and the nutrient content of the soil. You can improve both quite easily.
Improving soil texture
The physical texture of any soil can be improved by the addition of large amounts of organic matter. You can use materials like ground corncobs, sawdust, bark chips, straw, hay, peat moss, and cover crops; it's a great way to recycle a lot of garden wastes. You can use grass clippings, provided the lawn has not been treated with a herbicide or weed killer; these substances will damage the plants you want to grow. Also avoid walnuts or walnut leaves. They contain
iodine, which is a growth retardant. Making your own compost pile gives you excellent organic matter to enrich the soil and will be discussed later in this
chapter.
The more organic matter you add, the more you can Improve the texture of the soil. Blend the organic matter into the soil to a depth of 12 inches, making sure that it's evenly dispersed through the whole planting area. When organic matter is added to the soil, it will absorb some of the soil's nitrogen; to compensate for this, you should add two handfuls of a complete, well-balanced fertilizer (10-10-10) for each bushel of organic matter, working it
thoroughly into the soil.
Improving nutrient content
The next step in your soil-improvement program is to have the soil tested to identify deficiencies — unless you correct those deficiencies, they can cause poor plant growth. In some states the Cooperative Extension Service will act as middleman and send your soil sample to the laboratory for you; in all states the extension service can give you information on firms in your area that do the tests. Either way, you will be charged a fee for the test.
The results of the soil test will give you the pH (acid-alkaline balance) of the soil and its content of three essential nutrients: nitrogen (N), which promotes leafy growth (although too much nitrogen will encourage too much foliage growth and slow down crop ripening); phosphorus (P), which is important for root growth and the production of flowers, fruits, and seeds; and potassium (K), which is
necessary for the development of leaves and roots. The pH is measured on a scale of 1 (most acid or sour) to 14 (most alkaline or sweet), with 7 representing neutral. Most vegetables do best in soil that has a pH between 5.5 and 7.5, and most of them prefer soil to be on the acid side of neutral.
How to take a soil sample. Soil samples can be taken any time of the year, as long as the ground isn't frozen hard. Use a plastic bucket instead of metal, especially if the soil sample is to be used for testing micronutrients. You'll also need a digging tool, such as a spade or a trowel, and a clean container (a
carefully washed-out one-pint milk carton or the container provided by the testing service). All equipment should be perfectly clean.
If there's any grass on the spot you're sampling, remove it. Then take a slice of soil half an inch thick and about eight inches deep straight down from a number of locations throughout your garden. If you're sampling a large area, 20 samples mixed together will do as fine a job as 40 or100. if your garden is small, a minimum of five samples will be enough. Place all the samples in the plastic bucket, and then mix them thoroughly. If the soil is very wet, let it air-
dry before mixing. Do not heat it in the oven or on a radiator; heat will kill the microorganisms and cause nitrogen and other elements to change form, making the test inaccurate. If there are a lot of lumps, crush them with a wooden spoon or a rolling pin on a wooden surface. After the soil is thoroughly mixed, fill your container and follow the laboratory's instructions for sending the sample.
Adjusting the pH balance. The results of your soil test will give you the pH balance of the soil. If you're lucky, the laboratory may say that the pH is just fine and you need make no adjustment. Or the laboratory may advise you to raise the pH by adding a recommended amount of lime or to lower the pH by adding a recommended amount of a sulfur product — ammonium sulfate is the one most commonly used. Don't use aluminum sulfate in your vegetable garden; the aluminum can be absorbed by the plant, making it toxic to you when you eat the vegetable. You can get lime and sulfur products from hardware stores and garden centers; the laboratory report will tell you how much to use and how to apply it. It's a good idea to have your soil tested every three to four years to make sure that the pH is in an acceptable range. If you've had a problem with the pH, it may be a good idea to test your soil even more often. This may seem like a lot of work, but good soil is essential to a good harvest, and your care and labor will pay off in higher yields and better-quality vegetables.

FERTILIZING: HOW TO DO IT (AND WHY)
Many inexperienced gardeners have the idea that since their vegetables have been doing fine so far without fertilizer, they'll do fine without it next year, too. But it's not quite that easy. Certainly, your plants may provide you with vegetables even if you don't fertilize at all, but you won't be getting their best effort. Vegetable plants that are properly fertilized will be healthier and better able to resist disease and attacks from pests, thus giving you more — and higher-quality — produce.
Organic vs. synthetic fertilizers There are two types of fertilizer: organic and inorganic. They're both means to the same end, but their composition and action differ in a number of ways. Some people make a sharp distinction between the two, and organic gardeners — as the name suggests — are strongly in favor of organic fertilizers and strongly opposed to the use of synthetics. This
is more a matter of personal philosophy than of horticulture, because plants can't read the label on the package and can only absorb nutrients in an Organic matter has to take nitrogen from the soil in order to keep the decaying process going. Composting keeps the waste in one place where it's not depriving plants of nitrogen.
Composting can save money that you would otherwise spend on soil conditioners and fertilizers. It can save time, too, because it gives you a place to dispose of leaves and grass clippings. How the composting process works Compost forms as organic wastes are broken down by microorganisms in the soil. These microorganisms don't create nutrients; they just break down
complex materials into simple ones that the plant can use. Most soil organisms are inactive when soil temperatures are below 40°F; they don't begin working in earnest until the temperature goes up to about 60°F, and most of them don't work well in a very acid element. Because they are extremely small,
microorganisms work faster when not overwhelmed by large chunks of material.
There are two basic kinds of microorganisms:
those that need air to work (aerobic) and those that don't (anaerobic). It's possible to compost in an airtight container, thanks to the microorganisms that don't need air. A tightly covered plastic trash can will convert an enormous amount of organic kitchen waste into compost in the course of a winter. The classic outdoor compost pile should be turned regularly with a pitchfork to provide air for the microorganisms that need it.
How to start a compost pile
If you have a fairly large garden, the best place to put your compost pile is at one end of the garden. The pile can be square, rectangular or round; four to five feet across; and as long as the available space. You can use fencing or cinder blocks to keep the pile under control .
If space is at a premium or if a compost pile doesn't fit in with your landscaping, start the heap behind some bushes or behind the garage. If the space available is extremely small, you can compost in a large heavy-duty plastic bag or plastic garbage can. You can also work the material directly into the soil.
To build a compost pile, start out with one to two feet of leaves, if you have them, or six to twelve inches of more compact material, such as grass clippings or sawdust. Over this put a layer of fertilizer (manure, blood, bone, cottonseed meal, or commercial fertilizer) and some finely ground limestone (most microorganisms like their environment sweet).
Then add some soil to hold water and provide a starter colony of microorganisms. Water the compost carefully. Add a second layer of leaves or other garden waste and repeat the layers. If you have enough material or enough room, put on a third layer. The pile should be kept moist like a squeezed, but not sopping, sponge. As more material becomes available, make new layers, adding more fertilizer and lime each time. Turn the pile with a pitchfork about once a month. You can use all garden waste on your compost pile except disease- and pest-laden materials, or those that have been treated with pesticides or weedkillers— for instance, grass clippings from an area that's been treated with a herbicide. Use nontreated grass clippings, leaves, weeds, and sod. You can also use kitchen leftovers like vegetable and fruit peels, vegetable tops, coffee grounds, tea leaves, and eggshells. The finer these materials are chopped and the deeper they're buried, the quicker they'll be converted and the less chance there is that they'll be dug up by inquisitive animals. You can also compost hay, straw, hulls, nutshells, and tree
trimmings (not walnut). But unless they're shedded, these materials will take a long time to decompose. There are a number of ways you can speed up the composting process. First, you can grind or shred all. compost materials to give the microorganisms a head start. Second, make sure the pile doesn't dry out, and provide enough fertilizer to encourage rapid growth of the bacteria. Third, you can use a starter culture, either material from an established compost pile or a commercial starter culture.
Composting is a creative activity. There are
almost as many different methods of composting as there are gardeners, and like a good stew, the proof is in the final product. And when other gardeners see your compost pile, they'll know you're taking good care of your garden and that you're not just a horticultural dabbler. Compost and mulch — The difference is in the use If you're an inexperienced gardener, you may be confused by the difference between composting and mulching — both processes use waste organic matter. The difference is in the use. Composted materials are dug back into the soil to enrich it and to enable the plants to use the nutrients that have been released by the decaying process. A mulch is a layer of material spread over the ground or around plants to provide protection from heat or cold, to retain soil moisture, or to maintain a certain soil temperature. Compost stays in the soil and eventually becomes part of it; a mulch is removed when the protection it provides is no longer needed.

HOW TO GARDEN WITH HOPELESS (OR NO) SOIL
You may be unlucky enough to have a garden full of hopeless soil—heavy clay, perhaps, or as sandy as a beach. Even if you're sure that no soil improvement
program would help, you needn't give up hope of having a vegetable garden. It's not too difficult to you've probably been looking forward to planting your garden all winter. And you've probably been thinking it's the easiest part, too. What can be so complicated about planting a garden? Nothing to It. Mot so fast—there are a number of questions you have to consider before you start throwing seeds around.
For one thing, should you be planting seeds at all? Or should you be using transplants (young plants started from seed indoors)? If you're going to use transplants, should you grow them yourself or buy them from a nursery or garden store? And how should your crop be spaced—in rows, wide bands, or inverted hills? Like every other stage of growing a vegetable garden, planting poses a lot of questions; It's more complex than you may have figured.

SEEDS OR TRANSPLANTS: HOW TO DECIDE
The answers to the questions of what and where to plant depend on several factors: where you live, the kind of vegetables you decide to grow, and the amount of work you can reasonably handle. It's important to recognize your own limitations in terms of time, energy, and space. If you spend plenty of time at home, you may thoroughly enjoy nurturing your own transplants from seed. On the other hand, your home may not easily accommodate trays of young seedlings that need to be protected from cats, dogs, and curious children. And, if you're away a lot or know you're only going to be able to garden on weekends, you may want to give yourself a break and buy your transplants when you're ready to put them in the ground. Giving due consideration to practical matters like these will ensure that gardening is a labor of love — not a sentence to hard labor.
Growing transplants: Pros and cons
Starting at square one and growing transplants from seeds can be a challenging and satisfying activity. It saves money, and it gives you a chance to experiment with varieties you can't buy locally as transplants. That's the good news. The bad news is that growing transplants yourself requires time, space, and attention. If you only want a few plants or you're just embarking on the gardening experience, you may do better to have someone do the preliminary work for you. Also, these little plants are going to be the foundation of your vegetable garden, so if you can't give them the environmental conditions they need for best early growth, it makes sense to let them start off with someone who can.
Transplants can be temperamental The whole point of growing vegetables from
transplants is to make the best use of your growing season. If a crop needs a long, cool growing season and you know that where you live the weather's going to be hot as Hades long before you can expect to harvest, you're going to have to use transplants. You have to consider, however, the flexibility of the plant variety. Some plants survive transplanting without any problem. Some hate it. Among plants that make the adjustment without much difficulty are
broccoli, Brussels sprouts, cabbages, cauliflower, chard, lettuce, and tomatoes. Celery, eggplant, onions, and peppers are a little less tolerant and require some care in transplanting. Other vegetables, especially those with large seeds, resent transplanting and do much better when they're planted directly from seed after the soil warms up.
Among these more temperamental crops are beans, corn, cucumbers, okra, peas, summer and winter squash, and watermelons. If you start any of these vegetables indoors, you'll have to use individual containers that can be planted along with them in order not to disturb their sensitive root systems.
Your three-stage planting plan If you're planting a number of different vegetables, you will probably use all three of the systems we've mentioned. For instance, you may grow your own tomato and lettuce transplants from seed, direct-seed your peas and beans in the garden, and buy your young pepper plants from a garden center. In this case, your first task will probably be to start your transplants indoors, beginning eight weeks or more before your last date of average frost depending on the varieties you're growing. A couple of weeks later you can start direct-seeding — again timing your plantings according to the variety. Last, you can plant the transplants you purchased.
Good soil preparation is essential to all young plants. You'll be doing your soil preparation before direct-seeding, so the two procedures will be discussed together.

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