Control Pests Naturally in Your Raised Garden Beds

Raised beds offer unique opportunities for pest control thanks to their construction.

Why natural?Organic, non-toxic treatments insect damage slugs and snails Cats, rats & birds Protecting for long-term

Nearly every gardener has been there: you’re carefully tending a bed of fruit, flowers or vegetables, when somewhere between seedling and harvest an invisible pest moves in to take your plants down. Stems shrivel. Leaves disappear in a trail of slime.

Growing can seem like an uphill battle at times, but if you’re gardening in raised beds, you have some unique options available for tackling pests. Raised garden beds (also called garden boxes) lift your plants above ground level. They allow you more control over what’s going on around your plants thanks to their design and construction.

The case for natural pest control

Think of your garden as an ecosystem that needs diversity to thrive. Toxic chemicals can upset the delicate balance in your soil and garden ecosystem. Natural controls can help deter and eradicate pests by restoring balance and preventing problems in the first place.

Think of your garden as an ecosystem that needs diversity to thrive.

Even if you only have two or three raised beds, you can keep them healthy by encouraging a balance of healthy microorganisms, beneficial predators and companion plants. You can also avoid harmful pesticides by trying natural treatments first.

Not all natural treatments are costly and time intensive. Many are simple and easy to apply. Natural controls usually fall into a few different categories. We’ve listed these below to get you started.

What are the options for organic, non-toxic controls?

Biological controls

Often not the first choice in damage control, friendly garden predators and companion plants are the least harmful and most effective long-term solution for most garden pests. Nature abhors a vacuum and will fill whatever niche left open. Consider these the first line of defense for keeping your garden ecosystem balanced.

Barrier methods

Placing something in and around your garden bed that physically stop pests from getting to your plants is one of the soundest protections where practical. Common barrier materials include collars, fabric, fencing, mesh and more. While they sound expensive, some of them can be homemade from waste materials.

Foliar sprays and treatments

Mixes of organic materials applied to plant leaves and soil can often be extremely effective, depending on the pest. These are less useful in areas where rain or overhead sprinkling occurs regularly.

Soil surface treatments

These treatments are usually sprayed or dusted onto the soil surface of your bed. They can be particularly effective against soft-bodied pests like slugs and snails.

These methods can help you treat a variety of specific pest problems. Here are some of the most common ones you’re likely to face.

Ladybugs are just one of many beneficial predators that can help control garden pests.

Treating or preventing insect damage

Have you ever found tiny holes in your spinach or lettuce and wondered what caused them? From leaf miners to flea beetles, tiny pests that feed on tender greens can be hard to track down. But you can control their damage to your crops in the following ways.

Diatomaceous earth

Diatomaceous earth is a non-toxic product made from crushed diatoms—ancient freshwater plankton whose exoskeletons were made entirely from silica. It hinders the movement of pests in and around your fruits, vegetables and flowers. Apply to the soil’s surface in a continuous line around the perimeter of your raised bed. Its sharp edges (like microscopic broken glass) will prevent soft-bodies pests from entering the bed. To halt an infestation already underway, spread around the base of affected plants. Diatomaceous earth is effective until heavy rains wash it away.

Sticky traps

If you’re not sure what’s damaging your plants or if a particular pest is active, add an insect trap with a sticky surface to your bed. These can help you monitor which pests are in the area, making your decisions about pest control simpler. Placed in every bed, they can also help capture adult insects and prevent further reproduction.

Neem oil

This natural product is extracted from the neem tree commonly grown in India. Its leaves, seeds and oil contain salannin, a safe compound that repels insects.
Spray foliage with diluted neem oil concentrate to kill eggs, larvae, and adult insects for these common pests: aphids, spider mites, whiteflies, beetles, and leaf-eating caterpillars. Coat all leaves on top and bottom until thoroughly wet. Reapply after it rains.

Neem oil concentrate is an all-purpose, non-toxic substance that helps control insect pests and plant diseases.

Floating row covers

For pests that don’t respond to other controls, floating row covers are the answer. The thin white fabric made from spun polyester can be placed directly on the soil or stretched over a frame to contain your plants and protect them from outside invaders. If used directly on the soil, it will need staking with landscape staples or weights to prevent it from blowing around. Place these around your bed’s perimeter, making sure to leave enough slack for plants to grow.

For taller plants or row covers you want to leave in place all season long, build a frame made from PEX pipe and rebar (see details under “Rabbits” below). Raised beds make it easy to use floating row covers over a frame.

Beneficial Nematodes

Beneficial nematodes are microscopic organisms effective against over 200 different insects. These include cutworms, cabbage maggots, coddling moth, raspberry crown borer, beetles and root weevil larvae. They are often sold in a small sponge one million at a time.

In most cases you’ll mix nematodes with water and apply to the soil, where they hatch and go to work. They are harmless to humans and pets and won’t kill earthworms or harm pollinators. Applying beneficial nematodes in raised beds allows you to accurately target the larval stage of soil-dwelling pests. Just be sure to buy the right variety for the pest you hope to target, since different nematodes will prey on different insects.

Stopping slugs and snails

Those slime trails weaving through your tomato seedlings can only mean one thing: snails or slugs have moved in, and you need to act fast to prevent them from taking over. Thankfully raised beds offer you the chance to target your controls and make them more effective. Here are some suggestions to help.

Copper mesh

Control snails and slugs by fixing copper mesh “tape” around each bed perimeter. Slugs don’t like crossing copper. The reason isn’t fully understood, but some have suggested the way copper oxidizes into various toxic salts sends them in the opposite direction. Whatever the case, raised beds offer the perfect surface for installing copper tape in a continuous perimeter. Avoid putting too close the ground to prevent the copper from getting coated in dirt.

In a similar way, you can use a copper wire attached to a 9-volt battery, which will give the wet slugs a little zap. Just be sure to keep surrounding weeds down so plants don’t provide a bridge for adventurous slugs.

Diatomaceous earth

As mentioned above, this natural control works like tiny bits of broken glass to deter soft-bodied creatures. Slugs will avoid areas where it has been spread. Line your bed’s perimeter after hand picking any slugs already present, or dust around susceptible plants. This will stop further visitors.

Related: Natural Slug Control

Ferric phosphate

Another effective soil treatment is ferric phosphate, which is approved for certified organic growers. While it causes slugs to shrivel up and die, it’s labeled non-toxic to people, pets, birds, insects, earthworms and other wildlife. However, it’s important to note that the chelated form of ferric phosphate (containing EDTA) has been found to be toxic to dogs and other animals. Read labels and don’t overapply: tap a few pellets around the perimeter of your beds and near target plants.

Cats and rats and...

Larger pests can do damage in raised beds, which unfortunately don’t prevent climbing cats and scurrying rodents. But raised beds do make barrier protection easier and more effective. Read on for more details.

Rabbits

Raised beds 36 inches or taller will prevent rabbits from getting into your garden. Hardware cloth attached to bottom of bed and extended up the insides a few inches will prevent them from digging from below. If your beds are shorter than this and you have a rabbit problem, consider attaching a garden cloche or floating row cover to your bed frame. One simple method is driving metal rebar along the length of your bed at 24-inch intervals. Top rebar with PEX pipe bent to form a “U” shape. Cover this frame with plastic or fabric for instant protection.

Birds

Often targeting juicy, ripe fruit like strawberries and tomatoes, birds can reduce a harvest pretty quickly. Block their access with row covers or fine mesh stretched over a frame as described above. Just be aware that birds can get tangled up in netting that’s not pulled tightly across your bed’s span. While you want to reduce their access, you never want to cause harm. Many birds control insects and are a sign that your garden ecosystem is thriving.

A proactive approach to controlling bird damage is planting native fruiting bushes outside your garden. Leave wild areas like copses or hedgerows to preserve bird habitat and food sources and they will help control pests over the long term.

Some birds will feast on berry crops, reducing their quality very quickly.

Rodents

The first step to controlling rodent damage is identifying vulnerable crops and sealing them inside a protective barrier. Greenhouses can provide protection from rodents if installed on a solid surface and care is taken to seal up all cracks and crevices. Trapping is the most effective and safest method of control. Be consistent with setting and checking traps to prevent rodents from reproducing. Remove all food sources other than your crops, including bulk fertilizers. Store these inside metal cans with lids. Rodents will chew through plastic trash cans.

Cats

Cats like to dig in all types of garden beds and can unearth new seedlings before they’ve established strong roots. But they dislike prickly surfaces that can hurt their tender foot pads. If cats are digging around specific plants, pushing pine cones into the soil surface of your bed will deter them from visiting. You can also put chicken wire between plants around your bed’s perimeter—on the soil surface—to make your beds less welcoming.

Protecting your beds for the long term

Raised beds offer different methods of pest control thanks to their defined borders and height. Cultivating a healthy garden ecosystem is your first line of defense. Protection for targeted plants and pests will support your success.

To read more about how to create thriving raised beds, check out these posts:

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Control Pests Naturally in Your Raised Garden Beds

Raised beds offer unique opportunities for pest control thanks to their construction.

The case for natural pest control