Vegetable Gardening

by Charlie Nardozzi

  Botanical insecticides: Botanical insecticides are derived from plants. The most useful insecticides against vegetable pests are pyrethrins, which are derived from the painted daisy, Chrysanthemum cinerariifolium. They're broad-spectrum insecticides, which means they kill a wide range of insects. Unfortunately, that means some of the good guys are killed, too. So to avoid killing bees, for example, spray pyrethrins late in the evening. I usually use this pesticide as a last resort. The advantage to using pyrethrins is that it kills pests like aphids and beetles quickly, and has low toxicity to mammals. However, always follow the label and never apply more than is recommended.

  The terminology can be confusing. Pyrethrum is the ground-up flower of this type of daisy. Pyrethrins are the insecticide components of the flower. You also may see insecticides called pyrethroids, however. Pyrethroids, such as permethrin and resmethrin, are synthetic compounds that resemble pyrethrins but are more toxic and persistent. They shouldn't be used in organic gardens. Consequently, I avoid pyrethroids.

  Home remedies: Not all pesticides are exotic. Many gardeners have had great success using common household products to control insects in their gardens. One of my favorite home remedies is adding a clove or two of garlic and a few teaspoons of cayenne to a quart of water and then blending it all in a mixer. You then strain the solution to remove the chunks, and using a hand-held sprayer, spray your plants to control insects, such as aphids and whiteflies, and repel animals, such as rabbits and deer. Of course, after it rains, you have to reapply the mix. Commercial insecticide products, such as Hot Pepper Wax and Garlic Barrier, which are based on the common foods, also are available. Either type of product is effective, simple, safe, and fun to try.

  Insecticidal soaps: Derived from the salts of fatty acids, insecticidal soaps kill mostly soft-bodied pests like aphids, spider mites, and whiteflies. They also can be effective against Japanese beetles. They work fast, break down quickly, and are nontoxic to humans. Insecticidal soaps are most effective when mixed with soft water because soaps can sometimes burn tender foliage.

  Neem oil: Neem oil is extracted from the seed of the tropical neem tree. It has been used for centuries in India as an insecticide, to kill parasites in cattle, and even as a toothpaste for humans. Needless to say, it's very safe (except to unlucky pests). Home gardeners can purchase neem oil to repel and kill insects including aphids, whiteflies, leaf miners, caterpillars, and many others.

  Summer or horticultural oil: When sprayed on a plant, this highly refined oil smothers insect pests and their eggs. The words "highly refined" mean that the sulfur and other components of the oil that damage the plant are removed. This oil is relatively nontoxic and short lived. Use it to control aphids, mites, thrips, and certain caterpillars.

  Make sure that you don't confuse summer oil with dormant oil. Dormant oil should be applied to leafless trees and shrubs during the winter. It isn't meant to be used on vegetables.

  Double-check the oil's product label to make sure that you can use the oil on plants during the growing season. Then follow the mixing instructions carefully. Water your plants before and after applying the oil. But don't apply the oil if temperatures are likely to rise above 85 degrees Fahrenheit. When it's that hot, the oil can damage plant leaves.

  Even organic pesticides that have relatively low impact on your garden environment can be dangerous to use as well as toxic to humans; this is true of several commonly used botanical insecticides, such as pyrethrin and rotenone. Rotenone is a botanical pesticide that was used heavily in the early days of organic growing, but now has lost favor with many gardeners because of research showing a potential link to cancer and Parkinson's disease. I don't recommend it.

  Always follow the instructions on the product label exactly; in fact, not following these instructions is against the law. Also, wear gloves when mixing and spraying pesticides, and spray when the wind is calm. Store the chemicals in properly labeled containers well out of the reach of children (a locked cabinet is best). Dispose of empty containers as described on the label, or contact your local waste disposal company for appropriate disposal sites.

  Gardening to Eliminate Diseases

  Diseases differ from insects in that, with bugs, you can take action after you see them. With diseases, once you see symptoms, it's often difficult to stop the diseases from spreading. However, you can prevent or at least reduce most vegetable diseases by using good growing practices or by planting resistant varieties. Most vegetables have some varieties with disease resistance; see the chapters on individual vegetables in Part II for details. In the following sections, I provide useful methods for preventing and handling some common diseases.

  Avoiding diseases with good habits

  Here are some cultural practices that can help you avoid plant diseases:

  Remove infected plants. After you've identified a plant with a severe disease problem, yank out the entire plant. Even picking off infected leaves helps prevent a disease from spreading.

  Avoid overhead watering. Overhead watering can encourage foliage disease organisms to prosper. If you can't avoid this watering method, at least water early in the morning so plants have a chance to dry out before nightfall. Using drip irrigation or watering in furrows helps keep foliage dry (see Chapter 15).

  Space plants properly. Planting vegetables too close together reduces air circulation between them, a condition that favors disease and allows diseases to spread from plant to plant more readily. Keep your eyes open for developing problems.

  Keep your garden clean and tidy. Many diseases spread on plant debris, so rake up fallen leaves and remove dead plants. Also, keep the spaces under any containers clean. Removing diseased leaves can slow the spread of some organisms.

  Rotate plants. Don't plant the same vegetables in the same place year after year. Otherwise, you create a nursery for disease. Move things around as described in Chapter 16.

  Mulch your beds. A layer of mulch on the soil can act like a physical barrier, keeping disease spores in the soil and off the plants. See Chapter 15 for more on mulches.

  Watching out for common diseases

  The following list includes tips on how to prevent, identify, and treat (if possible) some common diseases that affect vegetables. Controls for diseases that are most troublesome for a specific vegetable are included with the description of that vegetable in Part II. Here are some diseases to keep an eye out for:

  Damping off: This disease attacks the bases of seedling stems, causing them to wilt and fall over. I discuss ways to prevent damping off in Chapter 13, which covers all aspects of growing vegetables from seed.

  Powdery mildew: This fungus coats leaves and flowers with a white powder. It's most common when days are warm but nights are cool. This disease is particularly troublesome to squash, cucumbers, melons, and peas. Controlling powdery mildew is difficult, but resistant varieties are available. The disease becomes less of a problem as the weather changes.

  Some gardeners have had some success using a home remedy. Mix 1 tablespoon of summer oil and 1 to 2 teaspoons of baking soda in 1 gallon of water, and then spray the mixture often to protect new foliage. This mixture also is sold commercially under names such as Remedy. Some forms of neem oil also are registered for use on vegetables. A new biological spray called Serenade (Bacillus subtilis) contains a bacterium that attacks powdery mildew and other fungi.

  Root rots: A number of soilborne fungi cause plants to have basically the same damage — regardless of whether the soil is moist. Lettuce is notorious for dying like this. The best way to prevent root rot is to make sure that soil drainage is good and to avoid overwatering — let the soil dry partially between waterings. Otherwise, all you can do to control root rot is to remove the dead plants. Few other control measures are effective.

  Southern blight: This rather nasty disease that affects corn is common in the southeastern United States. Southern blight causes plants to rot at the base of their stems, wilt, turn yellow, and die. Unfortunately, this
disease is difficult to control. Your best bet is to rotate your crops each year, get rid of all infected plant material, and turn your soil in the fall. You also can try soil solarization, as described in Chapter 15.

  My outlook on fungicides: Avoid 'em if you can

  Chemical fungicides (substances that kill fungus) are a nastier bunch of pesticides. I prefer not to use them on my vegetables. If you get a really stubborn disease in a prized planting, however, you may have no other choice. Here's a short list of some of the "safer" ones:

  Some mineral-based fungicides — such as copper for blight on tomatoes and sulfur for mildew on peas — are less toxic, but you should still use them only sparingly. They're most effective preventing the disease, so they need to be applied early.

  Neem oil also has been proven effective as a fungicide, making it another option. Like many fungicides, it's best used as a preventive spray or when the infection is just starting.

  Bacillus subtilis is a new biological fungicide that attacks many fungal diseases, such as mildew and blight. This bacteria is safe for bees, birds, wildlife, and beneficial insects.

  As with any pesticide, follow the instructions on the label carefully and exactly.

  Viruses: These diseases affect many vegetables, including tomatoes, peppers, peas, beans, cucumbers, beets, potatoes, and squash. When infected with a virus, leaves and fruits often have mottled yellow spottings and are deformed. Plants are stunted and die young, often not producing usable fruit. Virus diseases are sometimes specific to certain vegetables and spread by insects such as cucumber beetles (see Chapter 8 for more on controlling this pest), aphids, and whiteflies; stopping these pests many times stops the disease. You also should destroy infected plants and try to plant disease-resistant varieties.

  Keeping the Animal Kingdom at Bay

  Besides insects and diseases, you also should keep an eye out for the 2- and 4-footed pests described in this section. If you have problems with critters, be sure to properly identify the culprit; identification may take some late-night work with a flashlight. What control you use will depend on who's doing the damage.

  As you read the control suggestions in this section, you'll notice that fencing is one of my most common recommendations. But even a sturdy fence isn't a 100-percent guarantee, so live trapping and relocating may be the only solution to an especially persistent woodchuck or raccoon. (Check with your state Fish and Game Department to find out whether it has any regulations governing the trapping of the animal you have in mind.) You can buy live traps at most hardware stores; get the appropriate size for the animal that you want to catch. After you have the animal in the trap, release it in areas recommended by your local state Fish and Game Department officials.

  Letting your family dog or cat prowl your grounds to ward off wild animals may sound like a good idea, but, in reality, keeping your pets indoors or restrained is the best idea, especially when large animals are around. Rabies is a problem with many wild animals, such as raccoons, and some wildlife, such as woodchucks, which are ferocious fighters.

  The following list identifies animal pests that are common to vegetable gardens. It also provides some methods to control these critters:

  Birds: Starlings and crows have an uncanny sense of where you planted your corn seeds. To keep birds from eating seeds or pulling up newly sprouted plants, protect your seedbed with a bird tunnel (see Figure 17-4) or a floating row cover. By the time the plants outgrow the cover, they're no longer appetizing to birds.

  Figure 17-4: Covering seedlings with a portable bird tunnel is a sure way to keep birds away.

  Cats and dogs: Fences work best to keep four-legged friends — and your neighbors — out of your garden. Cats are a problem early in the season when they like to dig in newly tilled ground; laying chicken wire, pruned rose or raspberry canes, or hardware cloth over your seedbed until plants sprout encourages cats to dig elsewhere. Try spraying a pepper and garlic spray (see the earlier section "Methods of attack" for details) to deter these critters.

  Deer: A slanted fence can keep Bambi and her fawns out of your garden. Their instinct is to try to crawl under a fence before jumping it, and they're less likely to jump a wide fence. A slanted fence can be 4 to 5 feet high (see Figure 17-5); a vertical fence must be at least 8 feet high to keep deer from jumping over it.

  Gophers: Gophers can wreak havoc by eating plants' roots and underground parts. Trapping is the most practical solution in most cases. Probe the soil near a fresh mound of dirt with a crowbar, and set two traps in the runway, one facing each direction. Tie the traps together and cover them lightly with soil to keep out light.

  Figure 17-5: A slanted fence is the best design to keep deer out of your garden.

  If your garden is small or organized into small beds, you may want to construct a gopher barrier, as shown in Figure 17-6. Dig the soil out of the bed to a depth of at least 12 inches and line the bottom and sides with 1-inch chicken wire. Then replace the soil.

  Mice and small rodents: A 12-inch-high fence made of 1/4-inch mesh hardware cloth, with another 12 inches buried underground, keeps mice and other small rodents out of your garden.

  Figure 17-6: Fencing is the safest and most effective way to deter digging animals like gophers.

  Moles: Moles don't feed on plants; they eat insects such as grubs and earthworms. However, their tunneling may damage the roots of your plants. The most effective way to control moles is to repel them. Moles don't like the smell of castor oil, so spray a mole repellent, such as Mole Med, that contains castor oil.

  If the problem is severe, set traps in the tunnels. To find active tunnels, tamp down raised soil, which indicates tunneling. The tunnels that are raised the day after you tamp the soil are active.

  Rabbits: A 2-foot-high fence made of 1 1/2-inch mesh should keep rabbits out of your garden. Make sure the bottom is tight to the ground or bury the bottom edge as recommended for woodchucks. You also can try a pepper and garlic spray designed to repel cats and dogs.

  Raccoons: A 4-foot-high fence similar to the one recommended for woodchucks usually keeps raccoons out of your garden.

  Woodchucks: A fence at least 3 feet high with another 12 inches underground, curved away from the garden, is the best way to keep out woodchucks, also known as groundhogs (see Figure 17-7). Leave the top 18 inches of the fence unattached to support posts. This way, as the woodchuck attempts to climb over the fence, the fence will bend back down under the animal's weight. A strand of electric wire on top of a wire fence also discourages them.

  Figure 17-7: Build a fence to keep out woodchucks and raccoons, making sure to keep the top 18 inches unattached to the stakes.

  Chapter 18: Containing Your Veggies

  In This Chapter

  Choosing the right size and type of container

  Taking a look at potting soil

  Finding the best vegetables to grow in pots

  Planting and caring for container-grown vegetables

  Getting the scoop on greenhouses, hoop houses, and hydroponics

  You can grow almost any vegetable in a container; just fill a big pot with good soil, plant your chosen veggies, and then water and fertilize regularly. Why not just grow vegetables in your garden? Well, maybe you aren't a farmer with a big backyard and a 10-horsepower rototiller. Maybe your soil is more appropriate for raising worms than raising plants. Or maybe your garden is the balcony of your apartment or a tiny patio behind your condominium. You still have the right to fresh, homegrown tomatoes, don't you? You bet, and containers enable you to grow them.

  Containers also enable you to grow vegetables that may not be able to grow successfully in your garden. For example: If you've tried to grow eggplant in a climate with cool summers, but it never matured before the first frost, try growing it in a container. Because containers heat up fast in spring, vegetables get a head start on the season.

  Some people grow vegetables in containers simply because they like having their crops nearby — I certainly do.
With containers, you can bring your crops close to your house where you can see and enjoy them (and eat them at the peak of freshness!). Because containers are so easy to move (or because you made them that way by putting them on wheels), containers are the great equalizer; if you need a little more or less sun, you simply move the containers. (It's a heck of a lot easier than moving the sun!) Similarly, if frost is threatening, you can move the containers to shelter.

  Vegetables can be beautiful; I've seen pots of vegetables that are every bit as colorful as my favorite flowers. Whew, I'm getting excited about growing vegetables in containers! And that's what this chapter is all about: discovering how to get a bountiful and beautiful vegetable harvest from containers.

  Considering a Few Container Characteristics

  One trip to a nursery gives you an idea of just how many different styles and types of containers you can choose from. You can buy clay pots, glazed or not; plastic pots, pretty or ugly; or wood pots, big or small. And that's just the tip of the iceberg. Here are some things to keep in mind when choosing a pot for vegetables:

  Size: In most cases, pots that are bigger (in terms of width and volume) are better, especially for growing large plants like tomatoes. Lots of root space means that your vegetables are less likely to get cramped; they'll also be easier to water and fertilize. If you want to grow one head of lettuce in a small pot (8 inches in diameter), for example, you can do it, but you'll have to water and fertilize more frequently than if you had grown it in a larger pot. Although I've grown tomatoes in 5-gallon containers, I prefer at least the 15-gallon size.