Organic pest control is much more than not using harsh chemicals

An 'X' marked on image of a person spraying pesticides

This article aims to give you a holistic view of what organic pest control is. It includes an overview of the most commonly used organic pest control methods along with tips on how to properly implement organic pest control in your vegetable garden.

What is organic pest control?

Organic pest control isn’t just about not using chemical pesticides. Although that is the intended outcome, the process of implementing organic pest control methods involves creating a balanced vegetable garden ecosystem. This balanced ecosystem is able to support itself and make sure that all its individual components, including pests and diseases, are under control. This eliminates the need of using harmful chemicals to control and treat such problems.

Organic pest control methods

There are a number of different methods you can use to get rid of pests naturally. Organic pest control methods are not limited to natural alternatives to chemical pesticides that you can spray on pests. Some methods of organic pest control, such as companion planting, crop rotation, and encouraging beneficial predators, are important right from the planning stage of your vegetable garden.

The list below covers the most commonly used methods of organic pest control but is non-exhaustive. Some methods may work better on certain types of pests, so it’s important to choose a method that will work best for your specific situation.

1. Barriers and fences

When we think of pests, we usually only think of insect pests, but vegetable garden pests come in different shapes and sizes. Apart from insect pests, snails, slugs, birds, both wild and domestic, squirrels, rats, cats, dogs, and deer can all be pests in your vegetable garden. One of the simplest ways of stopping pests from getting near your vegetable plants is to fence or cover them. Fences and netting are suitable to keep larger pests away, while specific fabrics can be purchased to cover your vegetable plants to keep smaller pests away. In addition to pests, covering your vegetable plants can also help keep the plants warmer or away from too much sun, depending on the weather outside, and can also shield them from too much wind.

2. Biological pest control

Biological pest control uses predator-prey relationships in your vegetable garden to keep populations of pests under control. Predators of vegetable garden pests are encouraged into the garden by providing them with food, shelter, and if possible a suitable place to reproduce.

Beneficial garden predators include insects such as ladybugs, praying mantis, dragonflies, and lacewings, and also spiders, frogs, toads, and birds. The pests that these predators control and the different ways in which you can attract them into your garden are given below.

  • Ladybugs: Both adults and ladybug larvae feed on a variety of pest insects including aphids, spider mites, mealybugs, and other soft-bodied insects. You can encourage them into your garden by growing plants such as daisies, yarrow, clover, lavender, oregano, parsley, rosemary, sage, and thyme that attract them and their prey. Alternatively, you can buy ladybug larvae and release them into your garden. 
  • Lacewings: Lacewing larvae feed on the eggs and the young of a wide variety of pests, including aphids, mealybugs, thrips, spider mites, caterpillars, beetles, and whiteflies. Some adult lacewings also eat small insect pests, such as aphids and mites. Plants that attract lacewings include yarrow, coreopsis, cosmos, Queen Anne’s lace, chamomile, dill, fennel, golden marguerite, and lavender. These plants will provide food and shelter for lacewings. You can also provide them with some places to hide and lay eggs, such as overturned pots or small piles of sticks.
  • Praying mantis: Praying mantises feed on mosquitoes, flies, caterpillars, and beetles. You can attract praying mantises to your garden by planting flowering plants that attract bugs and by placing a few small sticks or branches for mantises to perch on while they hunt.
  • Hoverflies: Hoverfly larvae mainly feed on aphids and mealybugs, while larvae of certain species feed on ants, caterpillars, froghoppers, psyllids, scales, and mites. Adult hoverflies are not predators and instead feed on nectar and pollen. They can be attracted to the garden by planting pollen and nectar-rich plants, such as borage, lavender, rosemary, sunflowers, and yarrow. Once hoverflies have been attracted to the garden, they can be encouraged to stay by providing them with some sheltered places to rest, such as a pile of stones or a hedge.
  • Parasitic wasps: Parasitic wasps are tiny, almost invisible wasps that lay their eggs inside the larvae of other insects. Once the eggs hatch, the larvae are eaten from the inside out, which effectively controls populations of harmful pests. Their eggs are laid in pests such as caterpillars and aphids. You can attract parasitic wasps into your garden by planting flowering plants that provide nectar for the adults and also by providing nesting sites in the form of small tubes or blocks of wood. A compost heap will also encourage these wasps into your garden.
  • Dragonflies: Dragonflies are some of the most beautiful and beneficial insects around. They are usually found near ponds and can eat a large number of pest insects, such as mosquitoes, midges, and other small flies. You can encourage dragonflies to visit your garden by providing them with a shallow area of water where they can lay their eggs and plenty of water plants for them to perch on. Planting a variety of flowering plants, such as lantana, butterfly weed, Joe-Pye weed, asters, cardinal flower, swamp milkweed, dragon wing begonia, and coneflowers, will also attract adults.
  • Centipedes
  • Spiders: Spiders prey on a variety of insect pests and keep populations of pests under control. You can attract spiders to your garden by providing them with a pile of rocks, a stack of wood, or some other natural feature that they can use for shelter. Spiders also like to live on plants, including vegetable plants. If you see spiders or spider nests, which are small but easily visible white or off-white balls made out of spider silk, on your vegetable plants, you should not disturb or damage them. Spiders may bend the end of a leaf to create shelter for their nests, which may mildly damage the leaf edge but will not cause harm to the plant itself.
  • Frogs and Toads: Frogs and toads eat a variety of pests, including slugs, beetles, cutworms, and caterpillars. There are a few things you can do to make your garden more hospitable to toads and increase the chances that they will take up residence there. One is to provide a pond for them to lay their eggs in. The other is to provide them with shelter from the sun and from predators during the day. One of the most important things to do to make your garden toad and frog friendly is to not use any harsh chemicals. This is because they have sensitive and porous skin to help them draw up moisture from the environment, which can unfortunately also draw-up chemicals if they are present in your garden. Harsh chemicals not only cause disabilities in frogs and toads but can kill and eliminate entire populations. 
  • Birds: Many types of birds eat insects and all kinds of worms, while larger birds can even eat snails, making them useful for controlling garden pests. Attracting birds into the garden is easy. You can install birdbaths and feeders but your vegetable garden itself may be more than enough to attract them. Organic mulch and compost bins are also places that birds like to look around for insects and worms that they can eat.

The other methods of organic pest control given below are all naturally derived chemicals that are much milder than chemical pesticides available on the market. In contrast to the methods given above, the chemical methods of pest control should be used only when a large number of non-native pests or a pest infestation has been observed.

3. Homemade remedies

Garlic spray: Garlic emits a powerful smell that can be used to deter pests from your vegetable garden. Garlic spray is cheap and easy to make but is gentle enough to not harm you. To make garlic spray, simply crush or blend a few cloves of garlic and add them to a quart of water or boil them in water. Let the mixture sit for a few hours, then strain it and pour the liquid into a spray bottle. You can add a spoon of vegetable oil to make the liquid thicker and more likely to stick onto and trap pests. Some recommend adding dish soap into the mixture but I would rather not because soap can burn leaves and encourage diseases. Spray the garlic solution directly onto pests that are attacking your plants. The spray works best on smaller pests, such as aphids, spider mites, or whiteflies. Be sure to avoid spraying the solution on flowers, as it may harm them.

More information on using garlic for pest control

Hot Pepper spray: One of the most effective and least harmful ways to deal with garden pests is to use hot pepper spray. Hot pepper spray is made by mixing hot peppers with water in a blender. The peppers can be fresh or dried. Pour the mixture into a spray bottle and use it as needed. The spray can be used to protect plants from a variety of pests, including caterpillars, aphids, whiteflies, spider mites, beetles, and grasshoppers. Hot pepper spray works by irritating the insects’ respiratory system. It does not cause any damage to plants and does not cause any long-term harm to beneficial insects. It’s also safe for use around children and pets.

4. Companion Planting

Companion planting is a gardening technique that uses specific plant pairings to deter pests or improve the growth of other plants. It is an environmentally-friendly way to manage pests and can be used in both small and large gardens.

There are many different types of companion planting, but some of the most common methods involve planting plants that repel pests or attract beneficial insects. Companion plants that are ideal for repelling pests include marigolds, basil, lavender, mint, and garlic. Planting flowers alongside or as a border around your vegetable garden will attract insects, which will act as a food source to attract beneficial insects into your garden.

Many different combinations of plants can be used for companion planting. The companion plants of vegetable plants can be other vegetable plants, herbs, or flower plants. Some of the most common companion plant combinations used for pest control are tomatoes and basil, carrots and parsley, and potatoes and onions. You can experiment with different plant combinations to find the best ones for your garden.

5. Crop Rotation

Crop rotation can aid in pest control by preventing pests from finding suitable hosts and multiplying in numbers.

Many plant pests spend at least part of their lives in the soil. Pests that have remained in the soil will have direct access to a host plant if the same type of plant is grown again in an area that has been affected by a specific pest.

After a pest infestation, you should not grow the same crop or any other crops that may be harmed by that pest. Instead, for the next 2-3 seasons, grow a crop that is not affected by the pest in the affected area of soil, vegetable bed, or container. This way the pest won’t be able to remain in the soil without access to a suitable host plant and will naturally be eliminated from the garden over time.

6. Diatomaceous Earth

For centuries, diatomaceous earth has been used to control a variety of pests. Diatomaceous earth is a powder made from sedimentary rock formed from the fossilized remains of tiny aquatic organisms known as diatoms. It’s used as a natural garden pest control because it dehydrates and kills insects on contact.

When used in the garden, diatomaceous earth can be effective in controlling a wide variety of pests, including aphids, beetles, caterpillars, Colorado potato beetles, cucumber beetles, fleas, fruit flies, slugs, and whiteflies.

To use diatomaceous earth for garden pest control, first, shake the powder onto the plants you want to protect. You can also mix it with water to make a spray. Reapply after rain or after watering your plants. Be sure to wear a dust mask when applying diatomaceous earth to avoid getting it in your eyes.

7. Essential oils

Essential oils are derived from plants and can be used to repel or kill pests. They are a powerful, all-natural, and affordable way to keep pests out of your garden. In addition, they also have anti-bacterial and anti-fungal properties that can help to protect plants from disease.

To use essential oils as a pesticide, combine them with water in a spray bottle. Shake well before spraying. Be sure to test the mixture on a small area of the plant first to make sure it doesn’t damage the foliage.

Never use essential oils without diluting them first. Even though they are made from natural ingredients, they contain concentrates of the chemical compounds found in each ingredient and are too strong to be used as-is.  Be sure to avoid contact with your skin and eyes even when diluted.      `

Some of the most common essential oils and their uses for pest control are shown below.

  • Cinnamon essential oil solution can be sprayed directly on pests to kill them instantly.
  • Peppermint essential oil is a natural insecticide that is effective against aphids, whiteflies, thrips, and mites. It is also effective against mold and mildew.
  • Lavender essential oil is also an effective insecticide. It is effective against aphids, flies, beetles, and slugs.
  • Rosemary essential oil is a repellent for spiders, cockroaches, and ants.
  • Tea tree essential oil is a fungicide, herbicide, and insecticide that is effective against mold and mildew.
  • Basil essential oil repels mosquitoes, aphids, and flies.
  • Thyme essential oil repels cabbage worms, aphids, and whiteflies.
  • Garlic essential oil repels Japanese beetles, aphids, and spider mites.

8. Insecticidal soap

Insecticidal soap is made of potassium salts of fatty acids and can be used as a contact insecticide. It works by penetrating the insect’s outer skeleton and dissolving its internal organs.

Insecticidal soap is effective against a wide variety of pests, but is most effective on soft-bodied pests such as aphids, spider mites, and whiteflies, and does not work as well on larger insects, such as beetles.

Insecticidal soap should be used in an organic vegetable garden only as the last resort. It is a nonselective pesticide, meaning that it kills both good and bad insects. Despite this, it doesn’t harm other animals or humans.

How to implement organic pest control in your vegetable garden

# Don’t use pesticides and other harsh chemicals

The foundation of increasing the natural resilience of your vegetable garden against pests is to not use chemical pesticides or other harsh chemicals. This is because pesticides or other harsh chemicals can alter the natural balance in the garden, leading to a vicious cycle of highly-stressed plants that are not healthy and in turn attract even more pests and diseases.

# Grow healthy vegetable plants

Vegetable plants need to be healthy and free of other environmental stresses, such as too much exposure to sun or wind, a lack of water or nutrients, to be able to naturally deter pests away.

You can make sure that your plants are as healthy as can be by:

  • Planning your vegetable garden before you start growing anything. Planning starts by identifying the best location for your vegetable garden and choosing plants that suit both your needs and your vegetable garden to create the best layout for your vegetable garden.
  • Keep your vegetable plants properly watered. Watering your plants early in the morning or late in the afternoon, deeply watering plants that have a direct connection to the ground, and mulching will help your vegetable plants make maximum use of water.
  • Providing your vegetable plants with enough nutrients. Vegetable plants need a range of nutrients to be able to function properly. Adding compost to the soil or substrate that you will be growing your vegetable plants in will provide your plants with a balance of nutrients. In addition, you can add organic sources of nutrients, such as gypsum,  wood ash, bone meal, and fish meal, based on the needs of your soil and the plants that you are growing in them.

# Closely monitor your vegetable plants

As a vegetable gardener, you should make it a habit to spend at least a few minutes in your vegetable garden every day. This will help you to identify any changes in your plants so that you can take action immediately. Signs of damage to your plants, changes in the color of leaves, and the presence of a large number of pests may indicate that your plants are under attack.

# Take appropriate action if you see pests in your vegetable garden

As mentioned before, you don’t need to panic as soon as you see a pest in your vegetable garden, as long as your vegetable garden is healthy.

Your next course of action will depend on what type of pest it is.

  • A native pest? Be patient. If the pest is native to your area you need to be patient and give the predators some time to arrive and start working. If you yourself take action before the predator arrives, the predator may not arrive at all or may not have food when it arrives. If the situation has already gone out of hand, and predators still haven’t arrived or they have arrived but there aren’t enough predators, you will have to intervene.
  • An introduced invasive? Take immediate action. The problem with introduced invasive pests is that they usually don’t have any predators. This is why they have been able to thrive in a new environment in the first place. This means that you as the gardener will have to intervene. 

Once it’s time for your to intervene, your first mode of action should be to mechanically as many pests as possible away from your plants. If it is an insect pest, you can do this by aiming a strong jet of water directly onto the pests or by gently wiping the pests off leaves and stems using a tissue. If the pest is larger, you can install a fence, netting, or another physical barrier.

This can be followed if needed by a chemical form of organic pest control. You should always start with the mildest forms of chemical control, such as garlic spray, essential oil sprays, and dichotomous earth, and work your way up to stronger chemicals, such as insecticidal soap if the milder chemicals are not working.

This post has been selected as part of Twinkl Pets campaign and is featured in the  Why Are Bees Important to Humans + How to Save Them‘ post.

Organic pest control is much more than not using harsh chemicals

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