Vegetable Gardening Page 28

  Fall is a good time to test soil because labs aren't as busy. It's also a good time to add many amendments (materials that improve your soil's fertility and workability) to your soil because they break down slowly.

  To prepare a soil sample to use with a do-it-yourself kit or to send to a soil lab, follow these steps:

  1. Fill a cup with soil from the top 4 to 6 inches of soil from your vegetable garden, and then place the soil in a plastic bag.

  2. Dig six to eight similar samples from different parts of your plot.

  3. Mix all the cups of soil together; place two cups of the combined soil in a plastic bag — that's your soil sample.

  After you've collected your sample, consult the instructions from your soil test kit or the testing lab.

  If you're testing a soil imbalance — a known problem that you've identified in either pH or nutrients — you may want to test your soil every year because changes in pH and most nutrients are gradual. A home testing kit is a good way to test a pH imbalance. For nutrients, you may want to do a yearly test at a lab until the imbalance (high or low levels of a nutrient) is fixed. To maintain balanced soil, test it every 3 to 5 years.

  Adjusting soil pH

  Most garden soils have a pH between 5.5 and 8.0. This number helps you determine when and how to adjust your soil's pH level. The following guidelines help you interpret this number:

  If the number is below 6, the soil is too acidic, and you need to add ground limestone.

  If the measurement is above 7.5, the soil is too alkaline for most vegetables, and you need to add soil sulfur.

  In the following sections, I explain how to figure out how much lime or sulfur you need to add to your soil and how to apply the materials.

  Calculating how much lime or sulfur you need

  All Cooperative Extension Service offices, any soil lab, and many lawn and garden centers have charts showing how much lime or sulfur to add to correct a pH imbalance. The charts tell you how many pounds of material to add per 1,000 square feet, so you need to measure the size of your vegetable garden first. Then use Tables 14-1 and 14-2 to figure out how much lime or sulfur you need to add to your soil.

  In general, soils in climates with high rainfall — such as east of the Mississippi River (particularly east of the Appalachian Mountains) or in the Pacific Northwest — tend to be acidic. West of the Mississippi, where less rainfall occurs, soils are more alkaline. But regardless of where you live in the United States, you should easily be able to find the lime or sulfur that you need at your local garden center.

  Applying lime or sulfur to your soil

  The best way to apply sulfur and limestone to your soil is to use a drop spreader (the same machine you may use to apply lawn fertilizer). This simple machine doesn't cost very much, and it helps you spread the material more evenly. Some nurseries may even loan you a spreader or allow you to rent one inexpensively. You also can spread these materials by hand if you're careful and wear gloves. No matter how you spread the materials, make sure that you work the soil well afterward.

  You can purchase and apply different types of limestone to your soil. The type you use may depend on the type of nutrients your soil needs:

  Dolomitic limestone contains magnesium as well as calcium. Magnesium is one of the nutrients that a soil lab may test for, and even though it isn't in the top three (nitrogen, phosphorus, and potassium), it's as important as calcium for plant growth. Use dolomitic limestone to adjust the pH if your soil test shows that your soil is low in magnesium.

  Pulverized limestone is the most common and inexpensive acid neutralizer. Use this limestone if you don't need to add magnesium to your soil.

  Pelletized pulverized limestone is a little more expensive than ordinary pulverized limestone, but it's cleaner, less dusty, and easier to use than both dolomitic and powdered limestone.

  Sulfur usually only comes in powdered form or mixed with other nutrients such as ammonium sulfate.

  Your soil uses limestone and sulfur most efficiently when it's tilled into the soil to a depth of 4 to 6 inches.

  Adding organic matter (aka the dead stuff)

  If you're like most people, your garden doesn't have perfect loam soil. So to fix that mucky clay or loose sand, you need to add organic matter — once-living stuff like compost, sawdust, animal manure, ground bark, grass clippings, and leaf mold (composted tree leaves). You can't change the type of soil (clay, sand, or loam) you have, but adding organic matter makes your soil more like loam, which is perfect for vegetable roots. Even if you have loam soil, you still should add organic matter to your soil every year.

  What is organic gardening?

  Organic gardening has become a household term in the past 10 years. Many people are choosing organically grown produce from the grocery store because they feel it's safer and healthier. Because organic produce costs more than conventionally grown produce, it's a good idea to grow your own. And you're in luck, because throughout this book, I suggest ways to grow your vegetables organically.

  Organic gardening, in many ways, is just good, simple gardening practices and common sense. Some of the basic facets of organic gardening include the following:

  Feeding the soil — not just the plants — with organic fertilizers, manure, and organic matter (Chapter 15)

  Rotating crops (Chapter 16)

  Planting a diverse group of crops

  Solving pest problems by planting disease-resistant varieties

  Using barriers (covers that keep bugs away from plants)

  Releasing beneficial insects

  Using the least harmful biological and plant-based sprays (Chapter 17)

  The USDA now has a certification program for organic farms, and the fertilizers and pesticides that can be used on these certified farms are widely available at local garden centers and through the mail. But you don't have to be certified to grow plants organically. My philosophy in this book is to emphasize compost and soil-building practices and to suggest the use of sprays only as a last resort (and even then you should use only organic ones).

  Organic matter improves garden soil in the following ways:

  It helps loosen and aerate clay soil.

  It improves the water- and nutrient-holding capacity of sandy soil.

  It provides the once-living material that attracts microorganisms, beneficial fungi, worms, and other soil-borne critters that improve the health of your vegetables.

  Work some organic matter into your soil before you plant each season. If you're using unfinished (raw) organic matter like leaves or undecomposed manure, add it to your soil at least 1 month before planting. That way it will break down before you plant. Add finished compost and manures just before planting.

  Follow these steps to add organic matter to your garden soil (for information on the best kinds of organic matter, see the following sections):

  1. Add a 1- to 2-inch layer of organic matter to the area where you intend to plant your vegetables.

  Go for the higher end (2 inches) if your garden is new or if your soil is heavy clay or very sandy. Use less if you've grown there for years or if your soil is loamy and fertile.

  You need 3 cubic yards of compost to spread a 1-inch-thick layer over 1,000 square feet.

  2. Work in the organic matter to a depth of at least 6 inches.

  There's nothing glamorous about spreading manure. The best way to spread organic matter is with a wheelbarrow and a shovel. Work it into the soil with a shovel, iron fork, or rototiller.

  Another way to add organic matter to your soil is to grow your own. You can find out more about growing green manure and cover crops in Chapter 16.

  The best choice: Compost

  The best organic material to add to your soil is compost. Composting breaks down yard waste, agricultural waste, wood scraps, and even sludge into a crumbly soil-like material called humus.

  Compost is usually clean, easy to use, and available. You can buy it in bags or have it delivered by the truckload. Most wa
ste disposal sites make compost and sell it relatively cheap. You also can make your own compost; see the later section "Making Your Own Compost" for details.

  Before you buy compost, ask whether the compost contains any heavy metals, such as lead, and whether the compost is safe to use in a vegetable garden. Your local health department should be able to tell you what levels of lead and heavy metals are unsafe. The folks at the waste disposal site also may even be able to give you a precise nutrient content if they've performed any tests on the compost.

  Other organic materials, such as sawdust and manure

  Using organic materials other than compost — such as sawdust and manure — is fine, but these materials present a few problems that compost doesn't. Here are some advantages and disadvantages:

  Sawdust adds organic matter to your soil, which eventually breaks down and forms humus. However, the sawdust also robs the soil of nitrogen when it decomposes, so you have to add more fertilizer to compensate (see Chapter 15).

  Livestock manure improves your soil's nitrogen level (see Chapter 15 for more information on manure). However, livestock diets often include lots of hay that's full of weed seeds, which may germinate in your vegetable garden. Some manures (such as horse manure) add organic matter and some nutrients to your soil, but they're also loaded with bedding materials (like dried hay) that cause the same problem that adding sawdust causes.

  If you use manure, make sure it's fully composted — that is, it has been sitting around for a year or two, so it's decomposed, and the salts have been leached out. Too much salt in the soil can be harmful to plants. Good quality compost or fully decomposed manure should have a dark brown color, earthy smell, and have little original material visible.

  Turning Your Soil

  After adding nutrients and amendments to your soil, you need to mix them up. Turning your soil to mix the amendments enables them to break down faster and be available where the roots can use them.

  If your soil is dry, water well, and let it sit for a few days before digging. Then, to determine whether your soil is ready to turn, take a handful of soil and squeeze it. The soil should crumble easily in your hand with a flick of your finger; if water drips out, it's too wet.

  Don't work soil that's too wet. Working soil that's too wet ruins the soil structure — after it dries, the soil is hard to work and even harder to grow roots in.

  The easiest way to turn your soil, especially in large plots, is with a rototiller (or tiller, for short). You can rent or borrow a tiller, or if you're serious about this vegetable-garden business, buy one. I prefer tillers with rear tines and power-driven wheels because you can really lean into the machines and use your weight to till deeper. If you have a small (less than 100 square feet) vegetable plot, consider using a minitiller (see Chapter 20 for more details on this tool) or hand dig it if you're up for a little exercise.

  If you use a rototiller, adjust the tines so the initial pass over your soil is fairly shallow (a few inches deep). As the soil loosens, set the tines deeper with successive passes (crisscrossing at 90-degree angles) until the top 8 to 12 inches of soil are loosened.

  To turn your soil by hand, use a straight spade and a digging fork. You can either dig your garden to one spade's depth, about 1 foot, or double dig (that is, work your soil to a greater depth), going down 20 to 24 inches. After turning the soil, level the area with a steel rake, breaking up clods and discarding any rocks. Although double digging takes more effort, it enables roots to penetrate deeper to find water and nutrients. If you're double digging, dig the upper part of the soil with a straight spade to remove the sod and loosen the subsoil (usually any soil below 8 to 12 inches) with a spade. Replace the original topsoil often when you loosen the subsoil.

  Don't overtill your soil. Tilling to mix amendments or loosen the soil in spring or fall is fine, but using the tiller repeatedly in summer to weed or turn beds ruins the soil structure and causes the organic matter (the good stuff) to break down too fast.

  Making Your Own Compost

  Making your own compost is a way to turn a wide array of readily available organic materials — such as grass clippings, household garbage, and plant residue — into a uniform, easy-to-handle source of organic matter for your garden. Even though finished compost is usually low in plant nutrients, composting enables you to enrich your soil in an efficient, inexpensive way. You can add organic matter that isn't decomposed to your soil and get a similar result, but most people find that dark, crumbly compost is easier to handle than half-rotten household garbage — yuck.

  A compost pile (a pile of organic matter constructed to decompose) can be free standing or enclosed and can be made any time of year. However, you'll have the most organic matter in summer and fall when decomposition occurs faster due to the warm weather.

  Wire fencing makes a good container because it lets in plenty of air. You also can purchase easy-to-use composters at garden centers or through mail-order catalogs (see Figure 14-3). Some composters simplify the turning process (see "Moistening and turning your compost pile" later in this chapter), because they rotate on swivels or come apart in sections or pieces. They're easy to use, but usually aren't large enough for the amount of material produced in a large garden. You can build your own composter as well.

  In the following sections, I show you how to build, moisten, and turn a compost pile; I also warn you about materials that should never, ever go into a compost pile.

  Figure 14-3: Easy-to-use containers make composting simple.

  Building a compost pile

  Building a good compost pile involves much more than just tossing organic materials in a pile in the corner of your yard, though many people (including me at times) use this technique with varied success. Because, you know, everything does eventually rot. But to compost correctly, you need to have a good size for your pile, add the right types and amount of materials, and provide the correct amount of moisture.

  Here are the characteristics of a well-made pile:

  It heats up quickly — a sign that the decay organisms are at work.

  Decomposition proceeds at a rapid rate.

  The pile doesn't give off any bad odors.

  The organisms that do all the decay work take up carbon and nitrogen (the stuff they feed on and break down) in proportion to their needs.

  You can easily come up with the correct amounts of materials for a compost pile by building the pile in layers. Just follow these steps:

  1. Choose a well-drained spot in your yard.

  If you build your compost pile on a naturally wet spot, the layers will become too wet and inhibit the decomposition process.

  2. Create a 4- to 6-inch layer of "brown" materials that are rich in carbon.

  These brown materials include roots and stalks of old plants, old grass clippings, dried hay, leaves, and so on. The more finely chopped these materials are, the more surface area that decay organisms can attack, and the faster the materials decompose.

  3. Add a thin layer of "green" materials that are high in nitrogen.

  Green materials include green grass clippings, kitchen vegetable scraps, a 2- to 4-inch layer of manure, or a light, even coating of blood meal, cottonseed meal, or organic fertilizer high in nitrogen (see Chapter 15 for more on fertilizers).

  4. Repeat these green and brown layers (Steps 2 through 3) until the pile is no more than 5 feet high.

  If a pile is higher than 5 feet, too little oxygen reaches the center of the pile, enabling some nasty anaerobic decay organisms to take over and produce bad odors; I hate that. Five feet is a good maximum width for the pile as well.

  Here are a few additional ways to ensure success in your compost pile:

  Moisten each layer of your compost pile lightly with a watering can as you build it. However, don't let the pile get soggy.

  Cover each layer with a few inches of garden soil. The soil covers any material in the nitrogen layer that may attract flies, such as household garbage.

  Add a dus
ting of ground limestone or wood ashes on the carbon layer. This dusting keeps the compost's pH around the 6 to 7 mark that your plants like.

  Avoiding materials that don't belong in a compost pile

  A well-made pile heats up enough to kill off many insects and disease organisms, but the heating isn't uniform enough to be relied on to kill everything that you want it to. So don't add the following materials to your pile:

  Diseased or infected plant material: Disease organisms may survive the composting process and stick around to reinfect your plants when you apply the finished compost.

  Weeds that have gone to seed: The heat may not be high enough to kill the weed seeds. And then those weeds will show up in your garden.

  Pieces of aggressive weeds like quack grass or Bermuda grass: Even a small piece of a root can produce a new plant.

  Grass clippings from lawns treated with herbicides: Some herbicides may not break down during the composting process.

  Meat scraps and fats: They break down slowly and may attract animals to the pile.

  Dog or cat feces: They may carry diseases that can be transmitted to humans.

  Moistening and turning your compost pile

  After you build your compost pile, the decay process begins, causing the center of the pile to heat up. Proper moisture helps decay organisms to work properly. Following are some ways to keep your compost pile moist:

  Water the pile as needed. To determine whether you need to water, dig about 1 foot into the pile and see if it's moist.