Sustainability: Natural Methods for Garden Pest Prevention

Summer is in full swing, and there are so many things to do — picnics, trips to theme parks, family vacations, and one of my all-time favorite pastimes: gardening. As the owner and primary caretaker of a thriving organic micro-farm in Pennsylvania, I know that caring for your green, leafy friends is a year-round commitment, no matter your yard size or gardening goals. I also know that as wonderful as gardening can be, it can bring frustration and even feelings of defeat as you watch insects and other pests nibble their way through your hard work, trample over beautiful flower beds, and turn those bright green leaves yellow. 

When it comes to protecting your garden from larger pests like deer, groundhogs, and rabbits, sometimes the simplest solution is the most effective: a good fence. Sturdy fencing creates a physical barrier that discourages trampling, nibbling, and digging. To deter deer, aim for at least six feet high. For smaller animals like rabbits or groundhogs, bury the bottom of the fence at least 8-12 inches underground to prevent tunneling — groundhogs require at least 12 inches buried underground. If using mesh, hardware cloth or welded wire mesh offers better protection than plastic mesh, which is more likely to sag or tear over time. 

But if you’re looking for natural methods to try instead of a fence (or in addition to one), read on.  

There are several products marketed to gardeners as "pest control," but they tend to be expensive, and many contain harmful chemicals that kill not only weeds and aphids but also beneficial insects. Whether you have a raised bed full of tomato plants in your backyard or you're responsible for the storefront green space of a business, no one wants to coat their food, lawn, or welcome area with chemicals that can harm the environment and the people in it. This year, instead of buying overpriced chemicals to spray in your green spaces, why not try more natural products?

Read on to discover how easy it can be to "go organic" with some tried-and-true pest deterrents and insect prevention strategies. By the end of this article, you'll be ready to gather your supplies and start fighting back to salvage your green space for the last remaining weeks of summer.

1. Plants Protecting Plants

One of the most beautiful ways to keep pests in check is by using companion planting — interspersing pest-deterring plants throughout your garden beds or creating a "living fence" around your garden borders. 

Interspersing pest-deterring plants throughout your garden confuses insects and small mammals, disrupts their feeding patterns, and attracts beneficial pollinators to increase your flower, fruit, or vegetable yield. Creating a living fence around the entire space also attracts pollinators and, if done correctly, can deter smaller mammals from entering the space. 

Plants such as lavender, marigolds, basil, sage, salvia, coneflowers, and chives can be tucked between tomatoes, squash, or beans to make your space less appealing to animals (and some insects). Those same plants can be grown along the borders to act as a living fence. The key to a living fence lies in planting pest-repelling greenery densely enough to create a protective wall, while still leaving space for each plant to grow and flourish. This can be a tricky balance, so you might want to try creating a living fence line along only one garden border and then intersperse other plants throughout. 

Pro tip: Creating a fence line of tall and short-bunching plants, like lavender and chives or sage and marigolds, will provide each plant enough space to grow while still forming a tight barrier. Even better? Many of these aromatic allies pull double duty: Use lavender in tea, sage in marinades, and chives in almost anything savory.

To protect against deer, groundhogs, and rabbits: If you're specifically trying to discourage these adorable but destructive visitors, remember that they dislike strong scents, bitter tastes, and prickly textures. Aside from the companion plants mentioned above, you can also get help from rosemary, garlic, bee balm, foxglove, lamb's ear, and mint (though mint can be invasive and requires close monitoring). 

Groundhogs are less discerning than other visitors and can demolish a garden in one night. While pungent smells can deter them for a little while, groundhogs are more impacted by noise and movement. A motion-activated sprayer, light, or noisemaker will make more of a difference than noxious plants.  

Pro tip: Deer are well known for resisting almost any deterrent short of a six-foot-tall, reinforced fence. If you have a deer problem, no amount of lavender or marigolds will reliably keep them from their meal of choice. However, we have had success using thorny hedges in small grow areas. Hedges take effort and time to grow, but they have been worth it for us. Our various hedges of hawthorn, holly, blackberry (fast-growing and delicious), and firethorn have discouraged even persistent deer. Keep in mind that a hedge takes several years to fully develop, and you'll need to protect the shoots the first year and use other prevention methods as they grow.

2. Natural Sprays

On a micro-farm, there's just no way to grow and tend to enough barrier plants to cover our whole area, and, as I said, sometimes companion plants just aren't enough! Plus, not all pests have four legs and fur — in fact, most of our problems on our farm come from birds, insects, and fungus spores. That's why our battle regiment includes a variety of deterrents that can be sprayed, sprinkled, or hung around our vegetables and fruits. 

If you're looking for a potent spray-on deterrent, try the following homemade sprays:

General animal repellant: Combine 1-2 eggs, 2 tablespoons cayenne pepper (finely ground), and 2 tablespoons garlic powder per 1 gallon of water. Mix thoroughly and strain through a cheese cloth into a spray bottle. Wear gloves and be careful not to touch your face while handling. 

Groundhog repellant: Combine 1 part castor oil, 2 parts water and several drops of camphor oil. Locate and spray around holes, burrows, and garden borders.

Unneutered, uninvited cat repellant: I dearly love cats, but I don't appreciate stray cats using my garden as a litter box or marking it as their territory. You might find that cats (especially tomcats or young, inexperienced kittens) use your garden for their bathroom needs, especially in areas that are just starting to grow or a spot with a higher sand-to-soil ratio. We all know that spaying or neutering your cats and keeping them safely indoors is the best way to prevent these issues, but if you have a couple of neighborhood strays marking your yard, one surefire way to deter them is to use banana oil. You can purchase a large bottle on Amazon and dilute it with a 2:1 oil-to-water ratio, then spray it liberally all around the borders of your garden or porch area. As with all sprays, you'll need to reapply after a rain. However, purchasing a couple of large bottles at the beginning of the season should suffice. Cats are smart — it won't take long before they decide to just skip your yard and that nasty-to-them smell altogether.

Small rodent repellant: Small rodents can spell trouble for a number of reasons. If you suspect small rodents have been perusing your garden at night, you can use the sprays above, but because rodents are closer to the ground and better able to weave around smells they don't like, sprays aren't as effective. Rodents (mice in particular) are strongly opposed to the smell of mint, clove, eucalyptus, bergamot, and citronella. Make a simple deterrent using water, clove, and peppermint essential oil. Then, soak cotton balls in the mixture and place them strategically around your space.

Pro tip: Deer, rabbits, groundhogs, and several varieties of rodents are strongly opposed to the scent of Irish Spring soap. Buying a large package and tying the bars to fence posts or hiding them discretely amongst your vegetables can deter four-legged troublemakers for weeks. Just don't place the bars directly on the ground — not only will they dissolve quicker, but they will damage the plants around them. 

3. Netting

Birds can be a delight in the garden — they help with insect control and pollination and bring cheery songs on even the dullest days. Unfortunately, they can also decimate fruit crops and peck at tender seedlings. The key to maintaining a lush growing area is to deter birds from sensitive areas without endangering them — that’s where netting comes in.

Not all garden netting is created equal. Thin, loose plastic netting may seem like an easy fix, but it's notorious for trapping and injuring birds, leading to unnecessary suffering and even legal complications in some areas. Instead, opt for wildlife-safe netting with the following features:

• Small mesh size: Netting with holes no larger than a half-inch prevents birds from getting their heads or wings stuck while still protecting your crops.
• Taut installation: Sagging netting increases the risk of entanglement. Stretch it tightly over hoops, trellises, or frames.
• Durable material: Heavy-duty woven or knitted netting rather than plastic mesh will be more resilient, easier to reuse, and longer lasting.
• White netting is more visible and can stop animals and birds from approaching and becoming entangled. 

If you use netting, make sure to check daily for fallen fruit beneath the netting (which can attract other pests), and any signs of animal entanglement.

If you'd prefer to skip netting altogether or want to reinforce it with extra protection, consider:

• Reflective surfaces: Old CDs, pie tins, or commercial bird tape hung to reflect light
• Sound deterrents: Wind chimes or motion-triggered noise devices can discourage lingering
• Decoys: Owl or hawk statues, if regularly moved, can be effective

By combining safe netting with low-impact deterrents, you can protect your produce without posing a threat to birds.

4. Insect Control

Insects are among the most frustrating garden pests — but also the most misunderstood. While some cause real harm to your vegetables and ornamentals, many are essential allies: pollinators, predators of pests, and soil builders. The key to natural insect control is knowing when and how to intervene — and doing so in a way that preserves ecological balance.

Some of the best insect deterrents are the already discussed companion plants. Specifically, lavender is disliked by moths, fleas, and flies, and its essential oils deter mosquitoes — try a spray on yourself or your dogs before heading out to work in the yard. Spearmint and peppermint are particularly strong natural deterrents against ants, aphids, and squash bugs — consider planting it in containers near crops you want to protect to keep the mint from spreading. 

Other plants to consider include tansy and citronella. Tansy is an old-fashioned herb that doesn't get much love in modern landscaping, but its leaves contain compounds (including thujone and camphor) that naturally repel mosquitoes, ants, squash bugs, and even Japanese beetles. It's best used in moderation due to its potency — try planting it around the edges of your garden or drying the leaves for homemade sachets. Citronella is known for its mosquito-repelling oil and is most effective when crushed or activated by brushing against it. It's best grown in containers (to manage size) and placed near seating or entryways.

These plants don't eliminate pests, but they help create an unfriendly barrier that deters them from settling in.

5. Oils and Powders

If using oils and powders, be sure to use them with precision. Read on:

Neem oil is a natural extract derived by pressing the seeds of the neem tree. It works as an insect growth regulator and disrupts the feeding and reproduction cycles of soft-bodied pests like aphids, spider mites, whiteflies, and mealybugs.

A critical warning: Neem oil is not selective. If sprayed directly on beneficial insects like bees, butterflies, or ladybugs, it can kill them. That's why timing is everything:

• Only spray neem oil in the early evening, well after pollinators have returned to their nests.
•  Avoid spraying flower buds or open blooms. Focus on leaves, stems, and the undersides where pests congregate.
• Dilute according to instructions. Overuse does not increase effectiveness. A little goes a long way.
• Never apply before heavy rain, which will wash the treatment away, or during windy periods that could blow droplets onto unintended surfaces. For best results, apply every 7 to 10 days during high-risk periods (such as after several damp days or when pest damage has been spotted on the plant or its neighbors).
• Avoid spraying when daytime temps are above 85°F — excess heat combined with oil can damage leaves.

Neem oil possesses antifungal qualities and may aid in suppressing powdery mildew, rust, black spots, and anthracnose. To be clear, neem oil doesn't "cure" fungal issues — but it can slow the spread and prevent new outbreaks when applied regularly and correctly.

Keep in mind that seasonal shifts bring different challenges. Powdery mildew tends to flare up in late summer. Root rot often appears after heavy spring rains. Adjust your approach accordingly.

Diatomaceous earth (DE) is a naturally occurring silica-based powder made from crushed fossilized algae. It feels like powder to humans, but it's razor-sharp on a microscopic level and can damage the exoskeletons of insects, causing them to dehydrate and die. DE works especially well on ants, aphids, earwigs, slugs, and snails.

But, like neem oil, DE doesn't discriminate. If dusted on flowers or used on windy days, it can drift and harm bees and other beneficial insects. Always use these best practices:

• Apply only at dusk when pollinators are not active.
• Avoid using it on or near blooming flowers. Target the base of plants or specific infestations.
• Reapply only after rain or heavy dew, and always in light amounts. Overapplication can clog the soil and reduce its breathability. 

By combining deterrent plants with carefully timed treatments like neem oil and DE, you can protect your garden from pest damage without sacrificing the health of pollinators.

Pro tip:  Keeping plants watered  is critical, but how you water your garden plays a big role in fungal and bacteria spread. Watering plants from above, or overhead watering — particularly during the evening — can leave foliage moist overnight, creating ideal conditions for fungal growth and mildew to develop. Because of the splash, overhead watering is also more likely to contribute to the spread of fungus and bacteria.

Drip irrigation is one of the most effective solutions. Delivering water directly to the soil at the base of each plant keeps leaves dry, reducing the risk of leaf spots, powdery mildew, and other foliar diseases, and reduces the spread of soil-borne pathogens on lower leaves and stems.

When the Pests Come Inside

Even the most carefully maintained garden or green space can occasionally lead to uninvited houseguests. Always start with prevention and remediation. Seal gaps around all home entry points and use natural repellents near entry points and baseboards.

If you ever need to call in a professional, be sure to choose a pest control provider that uses eco-friendly, non-toxic treatments and offers targeted approaches rather than broad-spectrum sprays. We recommend Go Green Pest Control, Green Pest Solutions, or others you can find locally.   

Closing Thoughts

Gardening is one of the most fulfilling ways to connect with nature. Protecting your garden doesn't have to involve harsh chemicals or expensive treatments. With a few thoughtful practices, strategic planting, and a commitment to eco-friendly solutions, you can enjoy a healthier, more resilient garden.