Is the problem affecting the whole plant or just part of it?Having healthy soil and a healthy garden environment is the best way to prevent pest infestation and diseases. In this chapter, you will get advice on how to make your soil healthy and how to implement good gardening practices. No garden is without pests and diseases, but the important thing is to control them before they become a problem. The secret is taking the time to observe your garden. You can keep your plants healthy by using natural controls and promoting beneficial insects.
Find the Problem
Take the time every day or at least once a week to walk through your garden just to observe the plants. Ignore the weeds and do not stop to harvest; just take a few minutes to turn leaves over, check inside the cabbage leaves, and look closely at any insects or pests you may see. Doing this on a regular basis will allow you to catch problems early on. Is a certain plant looking less healthy than it did last week? Are those new holes in the leaves? Is something eating my spinach? Are those cabbage flies around my brassica plants? Do my tomatoes have spots or are they split? By observing the changes to your plants you can determine whether there is a threat to the plant and act quickly. If the problem is not obvious, you will need to be a detective to find out what could be wrong.
QUESTIONS TO ASK
Is the problem affecting the whole plant or just part of it?
Is the problem on one plant or on several plants?
Is there a pattern to it or is the problem random?
Is only a certain area of the garden affected?
Are only young plants affected?
Is there anything unusual on the underside of the plant leaves?
If you can see an insect or pest but do not know what it is, try to take a sample of the problem to your local nursery to see if they can identify the problem for you. A healthy plant will be able to fight a lot of problems, so give the infected plant a little more care and attention. Does it need more or less water? Has it been fertilized recently or is it overdue? If the plant is too damaged, pull it out and immediately place it into a garbage bag and remove it from your garden site so as not to spread the problem to other areas.
Ladybugs are a gift to any vegetable garden. They eat unwanted pests like aphids, mealy bugs, spider mites, thrips, and whiteflies. To attract them to your garden, plant marigolds, goldenrod, or butterfly weed. They can also be purchased at most garden centers or from seed catalogs.
Keeping a journal of any problems you have had in your garden this season will help you to plan for next season. You can use the successes and failures as a jumping-off point for tackling problems in future seasons.
Start with Healthy Soil
Having healthy, fertile garden soil is the best way to keep pests and diseases away. First, find out what kind of soil you have and correct any imbalances. Healthy soil will produce healthy vegetable plants. Healthy vegetable plants will not be stressed and will be less vulnerable to pests or diseases. Nutrient deficiencies, overwatering, and underwatering can make your vegetable plants more susceptible to pests and diseases.
If you till your soil when it is too wet or too dry, you can harm living organisms and earthworms in the soil. You can also change the soil structure, which can cause drainage problems, leaching of nutrients, and an overall unhealthy space for your plant roots to grow. Most gardeners are raring to go in the spring and want to get the garden going, but it is important not to till too early. Take the moisture test before you till in the spring. Squeeze a handful of soil. If it forms a firm hard ball, it is too wet; if it crumbles into dust, it is too dry. Soil that is just right will keep some shape but easily crumble when you squeeze it.
Most vegetables do best in soil with a pH between 6.0 and 6.9. Brassicas, spinach, and lettuce like it to be on the higher side. Tomatoes, peppers, eggplants, and most root crops can take the lower end. Squash, peas, beans, and onions prefer the pH to be right around 6.5.
Tilling or digging your soil in the fall will expose insects, larvae, and eggs to the elements, which can help destroy them. After you harvest an area you are going to leave bare, dig it up and let it sit for a week or so. Then either mulch the area or plant a green manure. Mulch will help keep the soil from getting too wet and will prevent leaching if you live in a rainy climate. On the flip side, mulch can also be a haven for pests such as slugs and can encourage mold and disease, so regularly check under the mulch for any larvae or eggs during the winter and spring.
Growing green manures is another way to keep your soil healthy. They are grown in the fall and help keep the soil from being blown away by the wind. Green manures also prevent erosion and leaching of nutrients. It is tilled under in the spring, which adds organic matter and nutrients to the soil, making it more fertile and healthier.
Good Gardening Practices
Maintaining a clean vegetable garden will go a long way to keeping it free of pests and disease. Trash, garden debris, and diseased plants can be a haven for many pests and diseases. Remove weeds from the garden after they are pulled out. They can be put in the compost bin or the trash if they have gone to seed. If you have any diseased vegetable plants, make sure you put them into a garbage bag immediately after pulling them so you don't spread the problem into other areas of your veggie garden.
If you find any pests, kill them on the spot by squishing them with your shoe or between your fingers. A good way to kill slugs is to cut them in half with your shovel. If you just place a pest on the ground or move it to another spot, it will be back! If you are squeamish about killing them, place them in a garbage bin and make sure they are not left on site. If the insect is too small to pick off and kill by hand, a good sharp spray of water can do the job. Spray infested leaves with an insecticidal soap or make your own insect spray to kill or deter harmful insects.
How do I make an insect spray?
Place the following ingredients in a blender: 1 garlic bulb, 1 small onion, 1 tablespoon cayenne pepper, and 1 quart water. Blend together and let the mixture steep for a few minutes. Mix in 1 teaspoon liquid nondetergent soap. Use immediately or keep up to a week refrigerated.
When harvesting, make sure all the fruit is removed from the garden. If there are any moldy fruits, place them into the compost rather than leaving them on the ground. When a plant is matured and no longer producing, pull it out and place it into your compost. Debris that is left in your garden beds or in the pathways can easily become a home for many pests and diseases.
Always have clean, sharp tools. Take the time at the end of each day to clean your tools. Scrape off any mud or dirt from each tool and give it a good spray of water to clean it. This will remove any pests. This is especially important if you have been working with diseased plants or in an area infested by pests. Every few weeks, take a little more care and wash the blades thoroughly with soap and water and then sharpen and oil them. A clean, sharp tool will make your life easier when working in the garden and will ensure you are not spreading pests and diseases around your garden.
To preserve the wooden handles on your garden tools, coat them with boiled linseed oil. This type of oil is thicker and dries quicker than the edible linseed soil. Simply rub the oil into the handle, allow it to sit for five to ten minutes to penetrate the wood, and rub off any excess oil with a clean, dry cloth.
Crop rotation is another essential practice to ensure a healthy garden. By growing your veggie plants in a different area each year, you will discourage pests and diseases in your soil. Each vegetable plant or family of plants requires different nutrients and attracts different pests and diseases. These pests usually live in the soil right where the plant was, so by moving your plants to a new area of the garden they will be less likely to survive. A good rule of thumb is not to plant the same vegetable or family of vegetables in the same area for four years.
Companion planting is another practice that can help to keep pests and diseases away from certain plants. In this method, certain plants are grown together so that they help each other. One plant may attract beneficial insects that will eat common pests, keeping the plants nearby healthier. Another plant may deter a pest, keeping the plant beside it healthier.
Keep Your Plants Healthy
To have healthy vegetable plants, you need to start with healthy seeds and transplants. Buy your seeds from a reputable seller or—even better—save your own seeds, especially if you find a certain variety that does well in your garden! A reputable seller should be willing to answer all your questions, provide you with information on where and how the seeds were grown, and give you growing tips. If your garden site is susceptible to certain pests or diseases, try to find seed varieties that are resistant to the problem. Seed catalogs have valuable information regarding different varieties of seeds. Choosing the right varieties of vegetable plants for your garden will help keep the soil and plants healthier.
When you purchase plants or transplants, make sure they are healthy. Many gardeners have unknowingly brought pests and diseases into their gardens via transplants. Look closely at any transplants you are planning to bring home. Check for any insects in the soil or on the undersides of the leaves, holes in the leaves, and evidence that insects have chewed the leaves. These are all signs that the plant may be infested. Make sure the plant looks healthy. The stem should be strong and thick, the leaves should be well formed and bright green, and the plant should not be root bound.
To quickly transplant your seedlings, use a bulb planter to make the holes. The hole is just the right size for individual plastic cells. Gently drop each seedling into the hole and cover it with the soil you pulled out. Firm the soil around the base of the plant.
When you set out your transplants or weed around them, make sure you do not damage the plant roots. Injured roots are more likely to attract pests and diseases, and a stressed or damaged plant will be less likely to fight off problems.
When planning your garden layout, make sure you calculate how many plants you will need. Most gardeners purchase too much and then think they have to squeeze all the plants into their garden. Plants need a certain amount of space to grow well, so be careful not to overcrowd them. Vegetable plants will grow better with good air circulation, which will help prevent mold or fungus on the leaves or fruit. Keeping fruit off the ground will also keep the plant and fruit healthier; if the fruit is touching the wet soil, it will often rot before it is harvested.
Correct watering is another important aspect to keeping your plants healthy. Most vegetable plants need at least one inch of water each week, although this will vary depending on the specific plant and your climate, rainfall, and soil conditions. Plants that get either too much or too little water will be more likely to attract pests and diseases.
Regularly fertilizing your vegetable plants will help keep them healthier as well. Record how much and when you fertilize them so you don't give them too much or too little.
Use Natural Controls
Okay, you have kept your garden clean, your tools clean, and you have tried to keep your plants healthier, but you still have some pest and disease problems. Do not fret—a few problems don't mean you have to throw it all in and quit. There are some easy ways to control any problems you may have. It is important to observe your garden on a regular basis so you can catch any potential problems early on; problems are much easier to handle if not too many plants are infected.
Larger pests or animals can cause a lot of damage in vegetable gardens. Deer, elk, raccoons, squirrels, opossum, skunks, gophers, and bears like vegetables just as much as we do. Take the time to observe what kind of animal is entering your garden. They often come out and feed at dusk or dawn. If it's not a wild animal, maybe your neighbor's dog or cat is sneaking in and digging up your plants. Keep watch to see what is causing the problem.
If you need to set physical traps to stop insects and other animals, consider the following:
• Set mouse traps.
• Put out a dish of beer to attract slugs or lay a board for them to crawl under and then destroy them.
• Use cutworm collars around the base of the plant to prevent the cutworm from climbing up the stem.
• Set out sticky yellow flytraps, which will attract the flea beetle. The flea beetle sticks to the trap and dies.
• Use row covers to prevent flea beetles, carrot rust flies, or cabbage flies from reaching the veggie plants so they can't lay their eggs on them.
• Build a fence to keep out dogs, cats, raccoons, bear, and deer.
Attracting predators that will eat your pests is another natural way to keep the cycle in your garden healthy. Grow flowers, herbs, and certain vegetable plants to attract birds, ladybugs, honeybees, and lacewings, which will keep a lot of your pest problems under control.
Harmful Pests Versus Beneficial Insects and Animals
When you first begin to garden, there is a lot to learn about which bugs are good for your garden and which ones are harmful. It takes time to get to know what is living in or entering your garden, and each year may bring a new problem. Learn by asking fellow gardeners, reading books, checking out the Internet, or asking questions at your local nursery or garden center. Vegetable gardening is a new experience each season because you cannot predict what will happen. Do not be afraid to experiment with new plant varieties and try out different natural controls. Stay away from pesticides when it comes to your vegetable garden; they will not make your soil healthier and will kill the beneficial insects as well as the pests. Attracting and keeping beneficial animals and insects in your garden brings you closer to having healthier plants and a more abundant vegetable harvest.
Birds, bats, toads, and snakes are all animals you want in your garden. They will keep slugs, snails, and many insects under control. All these animals need food, water, and shelter. Your unwanted pests give them all the food they need, but you may need to supply water and shelter for these animals in order for them to stick around. If you do not have an existing water pond or fountain, place some water bowls around your garden and keep them filled. Place a birdhouse in at tree near your garden. A bat house looks like a flattened birdhouse with a thin slot for the entrance; they can also be kept in trees. Use a clay flowerpot with a chipped rim as a toad house. Place the pot upside down near a water source. Snakes will live in a pile of rocks or a pile of sticks; just leave a bit of space in between for them to crawl into. Making a home for these animals will help control the ones you do not want!
Birds will keep harmful insects under control but will also eat your corn seedlings and strawberries. If the birds are eating the seeds, cover your seed beds with bird netting until the seeds have sprouted. Some gardeners tie colored tape to tree branches and fences, which can be effective in keeping the birds out of your garden.
There are as many beneficial insects as there are harmful ones. Each garden site has a variety of different insects and soil animals.
COMMON BENEFICIAL INSECTS
• Ground beetles
• Honeybees
• Lacewings
• Ladybugs
• Praying mantis
• Spiders
• Syrphid flies
• Tachina flies
• Wasps
• Yellow jackets
Planting flowers among your vegetables or letting some of your vegetable plants flower rather than pulling out the plant is another way to attract beneficial insects to your garden. The flowers add color to your garden, some are edible, and they can make your garden more attractive overall.
Lemon balm
FLOWERS THAT ATTRACT BENEFICIAL INSECTS
• Broccoli flowers
• Calendula
• California poppy
• Celery flowers
• Dill flowers
• Lemon balm
• Marigolds
• Nasturtiums
• Parsley flowers
• Sunflowers
Having a healthy ecosystem in your vegetable garden lets nature take care of things for you. Start with healthy soil, plant healthy seeds and plants, and create an environment that will keep everything in your garden in balance.
Common Diseases
You can physically see a pest or insect, but it is more difficult to diagnose a plant disease because the symptoms can be similar to those caused by other factors like excessive heat or cold, nutrient deficiencies in the soil, or poor drainage. Having healthy soil, giving your plants proper water and fertilizer, and maintaining good garden practices minimizes your plants' vulnerability to many diseases. If you do have a recurring problem, it is important to learn what it is and try to correct the cause.
There are four main types of pathogens that cause disease in vegetable plants—bacteria, fungi, nematodes, and viruses. They all attack plants in different ways but have some common symptoms such as wilting, yellowing, and stunted growth. The pathogens can be spread in various ways. They can be blown around by the wind or carried in water. Animals, humans, garden tools, and other equipment can also transfer them from plant to plant. Insects can carry a pathogen in their saliva and transfer it from plant to plant. When you are trying to diagnose a disease, it is important to learn the life cycle of the pathogen so you can avoid spreading it.
Before any disease can occur, three elements must be present in your garden: a susceptible plant, a pathogen, and favorable conditions for the pathogen to survive. To control or manage plant diseases, you need to remove one or more of these elements. A disease cannot develop if one of these elements is missing. Planting disease-resistant varieties of vegetables can remove a susceptible plant from this equation. Pulling out and destroying the infected vegetable plant removes the pathogen. You can make it difficult for pathogens to survive by creating an environment that is not compatible for them. For example, avoid overhead watering or take time to trellis a plant so it has better air circulation. Both of these measures make it more difficult for the pathogen to survive.
Aphids can easily spread viral and bacterial diseases. Controlling aphids often helps you stop the spread of the disease. Control aphids by attracting braconid wasps, hoverflies, lacewings, and ladybugs to your garden. An alternative is knocking the aphids off the plant with a strong stream of water.
The best way to keep your vegetable garden free of pests and diseases is to have healthy soil, to give your plants the proper amount of water, to use crop rotation, and to keep your garden and tools clean. A healthy plant will be better able to fight off anything that comes its way. No vegetable garden will be totally free of all pests or diseases, and remember that you want beneficial insects and animals to stay around.