Avoid Pests and Disease in Your Garden Naturally, by Following Smart Gardening Practices
As we enter fall and planting season for many crops, or tend to perennials and long-blooming plants, this is a good time to discuss natural ways to keep home gardens thriving and free of pests and disease.
The following are key methods that experienced organic gardeners use for keeping unwanted critters and blight out of their gardens.
Prevention: Regularly Remove Dead or Diseased Plants, Leaves and Flowers
The first step that an organic gardener takes to keep his or her plants free of pests and disease is to regularly inspect them for discoloration, damage, disease or dead leaves and flowers. The more you keep your plants healthy and remove dead parts, the more they will be able to withstand potential attacks from pests, and the less likely critters will be to invade them.
If you see a plant, a stem or leaves that look unhealthy (wilting when the weather isn’t hot, despite having enough water, for instance), pull out the stem or plant, or trim off the yellowing or infested leaves; this will help prevent an infestation from spreading to other leaves or healthy plants. Dead trimmings can be used for composting or mulching (more on these two later), but diseased trimmings must be thrown out, away from the garden.
Deadheading is important: deadheading is a term that simply means to snip off all dead flowers on a regular basis. Some gardeners leave dead flowers on the stem and just let them fall off on their own; however, it is better to cut off dead or dying flowers, as that will do three things: it will stop any of the plant’s energy from going to keeping the dead or dying flower on the stem; it will promote new blossoms; and it will prevent the dead flower from falling on the ground and serving as shelter for unwanted insects.
The more you maintain your flowering blooms free of dead flowers and dead leaves, the more fresh new blooms will grow during the blooming season.
To deadhead flowers, use gardening shears (also called pruning shears or “secateurs”); experienced gardeners advise not cutting right beneath the dead flower, but going down the stem, to where there is a new bud developing, or a healthy growth of leaves, then cutting a quarter inch up from the bud shoot or healthy leaf growth at a 45-degree angle. Snipping the dead flower / stem at an angle will help prevent disease.
Giving your plants the right amount of water that each needs, and maintaining a nutrient-rich soil will also help keep your plants healthy and more able to fight off organisms that may try to launch attacks on them.
Know When to Water Your Garden
Watering your garden early in the morning is ideal, as watering in the evening or at night is more likely to promote mold growth. You also don’t want to water the garden during the day when the Sun is beating down, as the heat will dry the moisture that you want to go to the plants.
If early morning watering is not possible, late afternoon is also okay, although as winds pick up in the later part of the day, more water may be lost to evaporation.
And speaking of water evaporation — in this day and age, many parts of our planet find themselves with reduced water supplies, due to persistent droughts. But we still have to eat, and indeed, growing one’s own trees, vegetables and fruits helps to clean the air we breathe in our communities, and reduces irreplaceable fossil fuels spent in getting produce and flowers to the stores, then making trips to buy these goods. In addition, most flowers and garden produce only keep a few days once picked — how great is it, then, to be able to go into your own garden and pick just what you need. So, the solution is to conserve water when gardening.
In addition to not watering plants during the hottest part of the day, it is also important to know how and how often to water.
Many people think that they need to water their gardens (and lawns) every day; but that is not the case. Too much water can quickly damage crops, just like too little water — roots need to breathe oxygen. When the soil has too much water, it actually decreases the roots’ ability to absorb water and minerals from the soil.
It is also best to do fewer, deeper waterings, than to do shallow, more frequent waterings: when you get water deeper into the soil, it encourages roots to reach farther down to get it. If you tend to do shallow waterings, the roots will stay closer to the surface, which makes them more susceptible to drought.
Horticultural experts advise that a vegetable garden needs one inch of water per week, either from rainfall or waterings. This translates to six gallons per square yard per week. Softer, clay-rich soil should get an inch of water once a week; sandier soil should get half an inch twice a week.
An inexpensive rain gauge can measure how much water your garden is getting, but you can also use observation to estimate: a sandy soil that’s dry 2 to 4 inches deep needs watering; in clay soil, if you can’t easily dig that far down, that means it needs watering.
Composting Nourishes the Soil and Improves Its Texture
Keeping a nutrient-rich soil can be greatly aided by composting. Composting is when you mix into the soil different all-natural items that have fully decomposed over the course of many months or even a year. These materials can include herbicide-free lawn clippings, leaves, citrus peels, coffee grounds, nut shells, wood ashes, wood chips, saw dust, pine needles, straw, crushed egg shells and others. You do not want to include items that will attract predators to the pile, like meat scraps, dairy, fruit pieces and so on, or diseased plants, or chemically treated items, including treated wood.
People who make their own compost, pile composting materials in their backyards, often in a wood container; but a compost heap can also be gathered in a plastic container inside the home, like under the kitchen sink. Home-composting is a topic all its own. If you would like to learn more, there are a number of websites online that address it in detail.
The easier way to get organic compost is to buy inexpensive bags of it at home improvement stores, gardening supplies or online.
When compost is fully decomposed, it is called “finished compost” or humus, and it has a mild, pleasant smell. (If compost has an unpleasant odor, it hasn’t yet finished breaking down.) The idea with compost is for its nutrients to be absorbed by the plants’ roots when plants are watered. So, you don’t want to place compost on the surface of the soil, but rather, mix it into the soil on the garden bed and around the plants’ roots. You can also mix it with the soil you use to start new plants or seeds.
A word of caution: compost should be distributed in a wider area than just next to a young plant’s roots, because if you just dump it in a small hole where you will place your plant, the plant’s roots may tend to stay near the compost, where they’re getting the most nutrients, meaning that they won’t grow too far out, which will limit the growth of your plant.
Mulch Protects Roots and Saves Water
Some people use the terms “mulch” and “compost” interchangeably. The two materials do have similarities, but there are differences. For starters, compost is usually mixed with or deposited into the soil. Mulch, on the other hand, is spread on the surface, around a plant’s stem.
While the primary functions of compost are to nourish the soil and improve its texture, mulch protects plants, especially young plants and seeds, from hot summer weather, by insulating the soil beneath. In the winter, when many plants are dormant, mulch helps keep soil temperature consistent. For example, in freezing climates, if the soil and roots are frozen, they remain frozen until the weather starts to warm up; this prevents damage to the roots or plant that can occur from alternately freezing and thawing during the winter. Mulch also helps prevent water evaporation (from heat), weed growth and soil erosion.
Like compost, mulch can consist of grass clippings, leaves, wood chips, shredded bark and other plant materials; but these can be used fresh, without being dried or decomposed first. (Expert gardeners advise shredding large leaves before using them for mulch.) Organic mulch materials decay over time and feed nutrients into the soil, but this release of nutrients is slower than that of composted materials, which are already broken down.
Mulch can also be inorganic, as in crushed rock or gravel. This type is used to insulate the soil, prevent water evaporation and control weed germination. It is also used because it gives gardens a pretty, “finished” look; many people are using it nowadays in drought-resistant landscapes and around succulents (plants with thick, fluid-filled leaves or stems, such as cacti, jade, ‘hen and chicks,’ ponytail palm, aloe vera, etc.). This mulch is best suited for perennials, as it is difficult to remove once it’s installed. A gardener should also be mindful that the small stones don’t escape onto areas of the garden like the lawn, where a lawn mower could be damaged by them.
Another natural strategy for maintaining the right levels of nutrients in the soil is to rotate crops. This is of special interest for gardeners who plant fruits and vegetables, as some of these crops absorb more of certain nutrients than others, and they deposit different nutrients into the soil. By switching where you grow your crops, you will balance the nutrients in the soil, and thereby promote plant strength and health.
Crop rotation also helps to prevent disease and pests because some microbes and insects tend to attack crops belonging to the same families; thus, by alternating where you plant your crops and not planting crops from the same family on the same section of the garden every year, you lessen the chance that disease-causing organisms that remain in the soil will infect the new plants.
If you decide to rotate your crops, it’s a good idea to draw a simple diagram each year, noting where and when you planted each plant, and compare this information from year to year.
Add Plants to Your Garden that Attract Beneficial Insects
Think of pest-consuming predators as your allies in keeping a pest-free garden. Grow some plants that beneficial insects love, and they will show up and eat undesirable pests, for free!
Beneficial insects include a possible assortment from the thousands of species of bees and butterflies that are native to North America. Both of these insects eat unwanted insects, as well as pollinate the garden. There are also ladybugs, wasps, lacewings, some fly species (including hover, tachinid and bee flies), and other insects. Aphids, also called plant lice, are a very common garden pest. Lacewings, ladybugs and wasps will eat them!
You can research the type of pest you’re concerned about, and find out what species are their natural predators; that way, you can attract the insects that will get rid of the problem for you. The delightful hummingbird, a species native to the American continent, is also an ally in keeping the garden free of pests, and as such should be courted as well.
Another important point to consider is that when you grow plants that attract and feed beneficial species, you not only protect your garden — you also help the ecosystem.
Many people are aware by now that bees, butterflies and other species that play an important role in pollination — a process that’s necessary for plants to flower, grow seeds and bear fruit — are dying and disappearing in record numbers, due to loss of habitat, urbanization and heavy use of toxic pesticides and herbicides. A lot of people want to help bring back these species that are essential to our survival. You can do your part in your very own garden, thus creating a win-win situation.
Bees, butterflies and moths feed on flower nectar, as well as pollen, which is rich in protein and vitamins. (They also enjoy eating rotting fruits.) As they go about collecting their food, they naturally pollinate plants. Grow nectar- and pollen-rich flowers and trees in your garden, and you’ll soon be attracting species that will eat your pests, while you also help the environment.
Below are some popular plants that attract beneficial insects and hummingbirds, and some that also repel pests in their own right. “Perennials” are plants that grow for 3 or more seasons; “annuals” grow for one season and need to be replanted the following year; and biennials are those that grow for 2 seasons but don’t bloom until the second year (though they still need care during the winter of their first season). Experienced gardeners often like to plant a mix of these three types of plants and stagger biennial plantings, to enjoy blooms every year.
Plants that Repel Garden Pests
For plants that will help keep pests and even unwanted wildlife away from your garden, you needn’t look any further than herbs, and others. Herbs have natural compounds that often (though not always) have strong scents, and give the herb its wonderful, distinctive aroma and flavor. These nature chemicals, generally non-toxic to humans and most species, can actually kill or sicken pests; as such, pests stay away from those plants and others near them.
All the herbs on the list above are good for repelling bad insects, while attracting beneficial ones. For example, if you plant dill, you will beautify your garden with its small, delicate yellow flowers, and feed beneficial insects … but the herb will also repel aphids, spider mites and tomato hornworms. When dill leaves are sprinkled on squash plants, squash bugs are repelled. As if all that weren’t enough, dill’s fresh fern-like leaves make a great seasoning for fish dishes, soups, pickles and salads, and they are packed with high amounts of many vitamins and minerals.
In addition to dill, the following plants from the preceding lists are aces at repelling garden pests:
Chrysanthemum — This beautiful flower comes in many bright colors and different designs. It has natural insecticides called pyrethrins, which are non-toxic to humans and pets, but kill pests.
You may have heard the term “companion planting.” This refers to planting certain crops together because one plant will help the other stay healthy by repelling pests, adding nutrients to the soil or even improving the flavor or yield of a plant’s fruit. Companion gardening can also maximize growing space in the garden, provide plants with shade, protect them from the wind, and so forth.
In the case of chrysanthemums, seasoned gardeners advise planting them in different parts of your garden to repel roaches, ticks, fleas, lice, silverfish and ants. White chrysanthemums repel Japanese beetles and kill root-knot nematodes (microscopic worms that live in the soil and feed on the roots of plants). Some advise making a tea from the flowers of any color, and pouring the cooled tea on other plants to combat the nematodes. “Mums,” as chrysanthemums are commonly called, are good next to tomatoes, but should not be planted next to lettuce.
Calendula — Also known as pot marigold, this is another pretty flower, which comes in bright yellow, light pink and orange tones. In old times, it was used to flavor foods like soups and give color to butter; but today, it is maybe better known for its uses in traditional medicine. Calendula tea is said to be tasty, as well as curative. Calendula is used for gastrointestinal discomfort and for cleansing the liver and gall bladder. The plant oil is used to treat skin conditions, including acne and eczema.
With their antiseptic power, calendula flowers repel most garden pests, including asparagus beetles and tomato hornworms. Plant near any vegetable or herb.
Basil — Oils in this tasty herb repel: thrips, flies and mosquitoes. Basil planted next to tomatoes is said to produce bigger, tastier tomatoes.
Garlic — This wonderful herb infuses beef, chicken, soups and vegetable dishes with lots of flavor. As an incredible bonus, its disease-preventing powers are legendary and have been known for millennia. With its strong antibacterial, antiviral and antifungal properties, garlic helps prevent disease in general, including many cancers and even the common cold. Garlic is a natural blood thinner, improving circulation and decreasing the risk of heart attack and stroke. It’s also been found in studies to lower blood pressure and cholesterol.
Garlic helps repel a number of garden pests, including: codling moths (whose larvae feed on apples and pears), Japanese beetles, aphids, carrot root fly, root maggots, snails and molds. Plant near tomato, cabbage family, eggplant. Avoid planting near legumes (beans, peas, etc.).
Sage — This aromatic herb with soft-textured leaves is known since ancient times for its varied health-promoting benefits. Sage is credited with having strong anti-inflammatory properties; people use it as a seasoning or a tea to help with inflammation-related conditions like rheumatoid arthritis, asthma and atherosclerosis. Sage has also been used historically to prevent cerebrovascular diseases such as stroke. Studies have found sage improves memory and may help prevent Alzheimer’s disease or slow its progression, as it improves blood flow in the brain.
Planted in the garden, this terrific herb repels the cabbage moth and carrot fly. Plant sage with perennial vegetables (but not with cucumbers or rue).
Borage — This annual herb is versatile and popular in traditional herbal medicine. Borage leaves are used to treat skin conditions, including eczema, and borage seed oil (also called starseed oil) is used to treat different ailments, including high blood pressure, asthma and gastrointestinal problems.
In the garden, this plant with the small star-shaped blue or white flowers repels tomato hornworm and cabbage worms. Plant near tomatoes, cabbage family crops, spinach and strawberries. Some gardening experts believe that borage actually helps all plants increase their disease resistance.
Catnip — As we know, this herb drives many cats wild. Whether fresh or dried, catnip leaves and flowers stimulate cats to become very playful, though they can also relax and doze off. Catnip is good for people, too, and it’s been used medicinally for millennia. Catnip tea is used to treat intestinal cramps, indigestion and even insomnia (pregnant women should abstain, as it can stimulate contractions).
Catnip is a star in the garden, repelling aphids, Japanese beetles, flea beetles, ants, weevils, spittlebugs and squash bugs. Plant near any vegetable. If you have a cat that loves catnip, it is best to leave space between the catnip plant and surrounding plants, so that your cat won’t harm these if it decides to roll around on the catnip.
Lavender — This plant with the elegant long stalks of small purple flowers is a favorite in many gardens. It has a number of uses; in addition to adorning bouquets, lavender flowers are dried and used in fragrant potpourris, and lavender oil helps soothe irritated and itchy skin. Lavender has a mild, menthol-like scent, which repels fleas, moths and mosquitoes. Plant anywhere that you want protection from these insects.
Marigolds — Although they are in different families, marigolds are sometimes confused with calendulas because they look similar. Marigolds come in bright yellow, orange, red or a mix of those colors. The flowers have the natural insecticides pyrethrins, and they repel several insects, including nematodes, Mexican bean beetles, whiteflies and mosquitoes. (However, they can attract slugs in cold, wet weather, and spider mites when the weather and soil are dry. Cultivate the soil around them often, to prevent slugs, and keep their soil well-watered, to prevent spider mites.)
Use marigolds that have their distinctive scent, to repel insects best. Plant near tomatoes, peppers, eggplant and roses.
Petunias — Lovely, delicate-looking petunias come in a wide assortment of solid and mixed colors. Plant them in different parts of your garden to add color — and to repel asparagus beetles, aphids, tomato worms, bean pests, potato bugs, squash bugs, leafhoppers and others.
Nasturtium (genus Tropaeolum) — This is another delicate-looking flower that comes in a number of bright colors, with round, flat leaves. Both the flower and leaves are edible and can be eaten as a salad or garnish. They have a peppery watercress-like taste.
Nasturtium repels many different garden pests, including aphids, squash bugs, whiteflies, cucumber beetles and striped pumpkin beetles. Plant near cucumber, cabbage family plants, squash, pumpkin, beans.
Sunflowers — These flowers can be magnificent; each stalk can grow from a few feet to many feet tall. Depending on the variety, the flower heads can be large, or really, really large! (About 1 ft. in diameter.) And once the flower dries out, you can feast on the many delicious sunflower seeds in its center! This beautiful flower with the tasty seeds repels aphids from nearby plants.
The above are by no means complete lists — there are many other plants that attract beneficial species, and there are other plants that repel pests. One of the inspiring things about nature is that we are given so many choices!
Expert gardeners advise that to help you decide what plants grow well in your area, you can plant varieties that are native to your region, and you can also look at what your neighbors are growing. Doing research online to learn more about specific plants you have in mind can also be helpful.
By Cynthia Sanchez. A graduate of the University of Washington, Cynthia has extensive experience writing about health and wellness topics for different media.