Would you like to deter garden pests from damaging your plants without harming your family, your pets, or the environment? Bugs are unavoidable but you don’t need toxic chemicals to keep them away from your flower or vegetable garden. Instead, use natural pest control methods commonly used by organic gardeners.
Let’s look at some pest control solutions you can safely use in your organic garden — their benefits, disadvantages, and other noteworthy info.
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Organic Pest Control Products
Neem Oil
A naturally occurring pesticide, neem oil is obtained from the seeds of the neem tree. Its active compound is azadirachtin, an ingredient that kills insects and keeps them from reproducing. Neem oil controls powdery mildew, aphids, rust, spider mites, whiteflies, and beetles. It can be used on houseplants, roses, fruits, vegetables, ornamental trees, shrubs, and flowers.
The product is also used as a fungicide.
Not all neem oil products are certified organic. Make sure you only use USDA certified organic neem oil products in your organic garden.
Disadvantages
- While it kills pests, neem oil can also harm some soft-bodied beneficial insects. Apply the solution only onto plant surfaces, not directly into the soil.
- Neem oil can be dangerous when ingested by infants or small children, sometimes causing diarrhea, vomiting, or seizures.
Diatomaceous Earth
Diatomaceous earth (DE) is made from fossilized skeletons of microscopic aquatic organisms. Their skeletons are made of silica, a natural substance that makes up part of Earth’s crust.
This organic pest control method works at a microscopic level, acting like tiny pieces of glass that kill bugs when applied directly on the plants. The sharp particles cut soft-body insects like aphids and caterpillars causing them to dehydrate and eventually die. Diatomaceous earth also works on hard-bodied bugs like cockroaches, fleas, and beetles when the silica finds its way into the bug’s joints.
Disadvantages
- The sharp edges that kill roaches and beetles will also kill bugs we rely on to pollinate our gardens, such as ladybugs, bees, and butterflies. Avoid using it on and near flowers and plants where pollinators will be visiting.
- Diatomaceous earth can be harmful to people, irritating your nasal passages. It can also dry out and irritate your skin and eyes.
Corn Gluten Meal
Extension agents at Cornell University recommend using corn gluten meal to inhibit the germination of weeds, noting it also wards off pests that feed on herbs. Corn gluten meal is harmless to humans.
It may take a couple of weeks, but corn gluten meal is a natural way to control ants in your garden. These tiny critters take the crumbs to their nests and eat, but they cannot digest them.
Things to note
- Many gardeners confuse corn gluten meal with cornmeal. The cornmeal in your pantry will not prevent weeds. Corn gluten meal is a byproduct created when making cornmeal.
- Extension agents at the Oregon State University dispute Cornell’s claims about its ability to control weeds, but they found it makes an excellent fertilizer.
Floating Row Covers
Floating row covers made of polypropylene- or polyester-based fabric, simple plastic covers, or canvas tarps help control aphids, thrips, cabbage worms, squash bugs, and other pests. They also deter squirrels, rabbits, birds, and other critters. The covers create a windbreak and retain heat while letting in the water, air, and light the plants need to survive.
Floating row covers also help control:
- Caterpillars on broccoli, cauliflower, and cabbage
- Maggots on corn and beans
- Beetles that like to munch on eggplants, cabbage, potatoes, and cucumbers
Things to note
- Lightweight covers don’t need supportive poles, are the least expensive, and are suitable for home gardens.
- Medium-weight covers help crops mature faster. They’re best for lettuce, carrots, radishes, and sweet corn.
- Heavyweight covers protect against frosts and freezes.
Beneficial Nematodes
Not to be confused with non-beneficial nematodes that will harm your plants, beneficial nematodes are microscopic, non-segmented roundworms that will kill soil-dwelling insects or insects in their larvae or grub stage. They don’t harm earthworms, but attack pests like Japanese beetle larvae, cutworms, root maggots, and grubs.
Beneficial nematodes will give you best results in small gardens since you must apply the right amount at the right time in order for them to work. Apply them too early in the season, and you run the risk of them dying if the ground temperature drops too low. Apply them too late, and you risk the heat killing them. The nematodes should be applied to the soil when pests are present in the soil.
Disadvantages
- Beneficial nematodes are a biological pest control method that will take longer to work than chemical pesticides. You may not see a decrease in the pest population until two weeks after the application, and you may need to reapply the nematodes to your garden every seven to 10 days.
- Since nematodes are living creatures, they have a limited shelf life and must be kept at a cool temperature.
- You must apply the species of nematode that is the correct size for the pest you’re controlling.
- Nematodes can die from exposure to sunlight or from drying out in the heat. Apply them in the morning or evening time when the soil is cool and moist
Mother Nature Knows Best: Companion Planting
Companion planting is the practice of growing certain plants together for the benefit of one or both of the plants. Some plants help repel pests or lure pests away from other plants. Some provide food for certain insects that control pests. Either way, companion planting helps you control garden pests without the need for pesticides.
What type of pests do you have? There’s likely to be at least one herb or flower that deters that pest. For example,
- Marigolds attract insects that kill aphids. Alliums and petunias also keep aphids away.
- Marigolds and petunias also repel leafhoppers, asparagus beetles, tomato hornworms, and squash bugs. Plant petunias next to basil and your tomato plants.
- Nasturtiums and chrysanthemums ward off aphids, beetles, ants, and cabbage loopers.
- Carnivorous plants, such as pitcher plants, trap and eat insects. These plants have evolved to avoid consuming beneficial pollinators.
- Garlic and onions repel tomato worms. Tangy chives are also good to grow alongside tomatoes and carrots.
Not all bugs and insects are bad for your garden; many are pollinators that are essential to the survival of the plants. By using natural pest-control methods like companion planting, you can deter undesirable insects without harming you, the planet, or the beneficial animals and insects that help your organic garden flourish.
Want more natural pest-control tips? Check out Organic Gardening: Ditch Pesticides for Good
About the Author
Todd Michaels is a conservationist with degrees in biology and botany. He writes about eco-friendly landscaping and recycling efforts around the country.
This article was originally published on April 14, 2022.