A garden will invariably attract some pests to it, but you can take certain measures to deter them or prevent a pest infestation from affecting your garden in the first place. Ideally, you want to create an environment that pests won’t like and set up barriers and anti-pest measures to kill the critters that do manage to break through.
Here are 15 tips on how to keep bugs out of a raised garden:
- Use insecticides.
- Plant pest-resistant seeds.
- Install physical barriers to fend off the pests.
- Install insect traps.
- Use diatomaceous earth.
- Keep toads and frogs in your garden.
- Attract beneficial carnivorous insects.
- Mix nematodes into the soil.
- Rotate the plants you grow each year.
- Plant different crops with each other.
- Harvest your plants on time.
- Keep some distance between your plants.
- Keep the plants healthy.
- Remove sick plants from your garden.
- Keep the garden clean.
In this article, I’ve put together an in-depth and comprehensive guide covering all the effective ways to get rid of pests from your raised garden and prevent a future infestation. Following that, I’ve also shared a short and simple guide on how to know if you have pests in your garden and whether the bugs/insects in the garden are beneficial or harmful.
1. Use Insecticides
The best way to kill pests residing in your raised garden and prevent new pests from coming in is by using insecticides.
Now, I understand if you want to keep your raised garden free from insecticide and pesticide. But what if I told you there were organic pesticides that won’t damage the plants or harm you but effectively deter pests away from your garden?
If that interests you, then you could try using the EcoGarden Organic Pesticide (available on Amazon.com). It’s perfect for ornamental plants, flowers, trees, landscape planting, garden vegetables, fruits, berries, etc. Furthermore, the pesticide is completely safe for humans, pets, and even honeybees, which helps with pollination.
You can also try DIY concoctions of homemade pesticides if you feel proactive.
A simple water-based solution using neem oil, garlic, baking soda, essential oils, and biodegradable dish soap is enough to kill or deter most common garden pests. To use this solution, put it inside a water sprayer and coat the plants/corps as well as the soil with it.
There are a lot of natural & homemade insecticide recipes that you can try, depending on what you have on hand.
2. Plant Pest-Resistant Seeds
You might think that pests and insects cause a plant to get sick, but it’s actually the other way around. Pests specifically feed on sick plants and generally leave healthy plants alone.
As such, keeping your garden plants healthy and disease-free is one way of keeping pests away from the area. You can keep your garden healthy with regular prunings, a water schedule that suits your plants, and clearing dead leaf matter away from the ground.
However, it is just as important to start with a healthy garden with plants that are less likely to get sick and diseased. You can do this by opting for pest and disease-resistant plant seeds. These are usually available at your local nursery, but if not, you can also order them online.
Seeds that are disease or pest resistant will usually have the letters F, N, T, and V after their name. Each letter means resistance to the following:
When you’re buying these disease-resistant seeds, just make sure they’re from a trusted brand that has thoroughly tested the seeds and meets all the necessary guidelines.
3. Install Physical Barriers To Fend Off the Pests
If you have successfully killed/removed all the pests in your garden and simply want to protect your plantation from further pest invasions, you can install a physical barrier. These are excellent at fending off most garden pests, if not all.
I prefer using plant covers like the Valibe Plant Covers (available on Amazon.com) to protect vulnerable crops in my raised garden. These are lightweight, thin fabrics made by spinning polyester and especially effective at fending off pests.
You can stretch the fabric over a frame to lock in all your plants inside and safeguard it against all outside pests.
Alternatively, you could also protect individual plants by placing the fabric directly on the soil and covering the plant with it. That said, if you choose to do it this way, make sure to use landscape staples to secure the fabric in place, or it can blow away.
Now, while plant covers will keep surface-level pests at bay, you can install pieces of cardboard near the plant stem to deter underground burrowing insects. Ensure the cardboard piece goes at least 1-inch (2.5 cm) deep into the soil for the best results.
Other than this, you could also try mulching, where you put a layer of cedar or cypress bark over the soil. It’ll effectively repel various types of nibbling insects off the soil, thereby safeguarding your plants.
4. Install Insect Traps
Alongside physical barriers, you can also install dedicated insect traps to double the protection of your raised garden.
I’ve found that sticky pads are super effective at capturing insects in my raised garden. These should be available at your local nursery. But if you can’t find them, you can check out these Gideal Dual-Sided Yellow Sticky Traps (available on Amazon.com).
It’s made of non-toxic, eco-friendly materials and will not only trap but also attract different garden pests, including whiteflies, fungus, gnats, blackflies, fruit flies, and so on. However, to increase its efficiency, you’ll need to place them strategically surrounding the garden.
Ideally, you should surround the ground near your raised garden with these sticky pads to catch ground insects. To catch the aerial bugs, you can place them between the branches or shoots of some crops/plants.
Other than this, installing insect traps also helps you keep an eye on the different kinds of pests in your garden.
Suppose you find that the plant leaves or flowers in your garden were damaged overnight, but you can’t find the culprit in the morning. Well, installing an insect trap will help you catch the pest. This will help you create a targeted pest control plan that’ll be more effective and economical.
5. Use Diatomaceous Earth
Another useful and organic way of deterring away soft-bodied grounded pests like slugs from wreaking havoc in your raised garden is by using diatomaceous earth. It’s also effective at killing smaller crawling insects and helps to stop an infestation that’s already underway.
You can usually find diatomaceous earth at your local nursery, or you can buy it online. I prefer using the Safer Brand Diatomaceous Earth (available on Amazon.com). It’s relatively affordable, OMRI listed, and perfect for attracting and killing crawling insects like roaches, ants, fleas, silverfish, earwigs, and much more.
In case you’re wondering, diatomaceous earth is basically the crushed fossilized remains of diatoms – an ancient aquatic organism with an exoskeleton made from silica. It’s generally sold in powder form and is very coarse.
When insects come in contact with the powder, it damages their exoskeleton. This will keep the insects from coming too close or damaging the exoskeleton so much that the critters will dehydrate and die.
You can apply diatomaceous earth on your raised garden by directly spreading it on the soil surface in a continuous line, creating a perimeter around the raised bed. Alternatively, if you already have an infestation, spread the powder around the base of the infected plant.
It’s worth remembering that diatomaceous earth will not work against flying pests. Also, rain and watering will wash the powder away, making the garden vulnerable again. As such, you need to apply the power each time after it rains or you water your garden.
6. Keep Toads and Frogs in Your Garden
One way to combat pests feeding on your garden is by inviting animals to feed on the pests.
Toads and frogs are particularly useful in this regard.
If you have a significantly large raised garden, you can build a toad house somewhere in the middle and keep a bowl of water near it. If insects come by, the toad house will be a welcoming habitat for toads and frogs, with enough bugs to feast on.
Here’s a quick 4-min YouTube video on creating your own toad house:
That said, if toads and frogs aren’t coming in voluntarily, you can also catch a few and place them inside your garden manually.
7. Attract Beneficial Carnivorous Insects
Just like some animals eat plants, and some eat animals, there are predatory insects that devour plant-eating pests. If you create a hospitable environment in your garden for these beneficial insects, they’ll quickly clear out your pest problem more efficiently than any pesticide could ever do.
Furthermore, beneficial insects will naturally come to your garden. The problem is realizing which insect is beneficial and which is not, so you don’t shoo away the good ones from your plantation.
As such, educating yourself is important so you can easily identify the beneficial insects, including their eggs and larvae. Here are some beneficial insects that can help keep other bugs out of your raised garden:
- Praying Mantis
- Parasitoid wasps
- Damsel bugs
- Minute pirate bugs
Remember that these carnivorous insects prefer to feast on protein-rich insects alongside carbohydrate-rich nectar. As such, I recommend planting a floral architecture nearby from where the insects can get their sugar.
Some plants like yarrow, sunflower, and meadowsweet will attract beneficial insects to your garden, who can take care of bugs that might damage your plants.
8. Mix Nematodes Into the Soil
If you like the idea of introducing beneficial insects into your raised garden, you can also consider mixing nematodes into the soil.
Nematodes are small parasites that live in the soil and target the larvae of up to 200 different types of soil-dwelling pests, including beetles, cabbage maggots, root weevil larvae, cutworms, and much more.
That said, not all nematodes benefit plant growth, and some can hinder proper plant development. Also, different varieties of nematodes attack specific types of pests, and a single type of nematode won’t rid your garden of all your pest problems.
As such, first research which pest infestation you have in your garden and get the variety that’s equipped to handle that pest. You can contact your local nursery or gardening stores to find nematodes that’ll work for the pests in your garden. They are usually sold in a small sponge containing up to 1 million nematode eggs.
You can mix the eggs with water and directly apply them to the garden soil. After some time, the eggs will hatch inside the soil and start killing the pest eggs.
9. Rotate the Plants You Grow Each Year
It’s important to note that a lot of pests only feast on certain types of plants and leave others alone.
As such, if you only plant a certain kind of crop in your raised garden every season, the pests will know that there’s a consistent food supply there and will build a habitat around it. This will also raise the pest problem with time.
However, you can easily combat this by practicing crop rotation – where you plant different crops in the same area each growing season.
As a result, the pests feeding on the crop you grew during the first seasons will have no food source the next season and will have to migrate. Yes, new pests might come in, but it’ll take a lot of time for them to grow in numbers. And by the time their numbers rise, you’ll have replaced the crops with another new batch.
Of course, this technique won’t absolve your raised garden of pests, but it’ll significantly reduce their numbers and make the problem much more manageable.
10. Plant Different Crops With Each Other
Apart from practicing crop rotation, you should also try to raise different types of crops in the same bed – something known as intercropping.
Here, the idea is to plant different varieties of complementary crops together so that one crop fends off the insects attracted to the other and vice versa.
As an example, squash bugs are primarily attracted to squash plants. However, growing royal acorns in the same bed as your squashes will deter the squash bugs.
Granted, you need to do a lot of research to learn which plants best complement each other. Furthermore, there’s also the possibility that you don’t need/want to plant the other “complementary” plant.
In that case, I recommended planting general pest deterrent crops like garlic, marigold, or any plant with a strong aroma. The smell will fend off most pests. Moreover, these fragrances attract beneficial predatory insects, which should help.
11. Harvest Your Plants on Time
Fully ripe fruits and vegetables are like a neon welcome sign for pests. As such, it’s crucial that you don’t fall behind on harvesting your crops at the right time.
If fruits like tomatoes, squash, and pumpkins fall off the plant, take them out of the garden asap. It won’t take long for the fruits to spoil and attract pests.
Likewise, sometimes ripe fruits cling to the plant and don’t fall off. In that case, pluck it manually.
In some instances, you’ll notice that fruits and vegetables stay attached to the plant and grow abnormally large. In that case, harvest the fruit and give the plant some water and manure so it can recoup. Bearing such a large fruit will drain the plant of necessary nutrients, which can make it sick, turning it into a prime target for pests and insects.
12. Keep Some Distance Between Your Plants
Plant your crops such that there’s a noticeable distance between them.
I know it can be tempting to plant crops together in clusters trying to utilize the most area out of your raised garden.
However, if you have a lot of plants packed together, it cuts off proper air circulation. A lack of airflow creates a humid environment and also provides a sheltered area safe from sunlight.
As you can clearly imagine, this creates a highly hospitable environment for pests where they get access to food and shelter. What’s more, it’ll also become difficult for you to locate any damage done to the plants.
However, if you maintain ample spacing between each plant, it’ll be easier to locate the pests and take prompt action. Even birds and other predatory insects can quickly locate the pests and kill them, thereby aiding you in safeguarding your garden.
13. Keep the Plants Healthy
Earlier in this article, I talked about how you should use disease-resistant plant seeds so that the plant turns out healthy and doesn’t attract insects.
However, even if you don’t use specialized seeds, you should take measures to keep the plants as healthy as possible since a healthy plant can fend for itself and deter most pests.
To do this, remember to water your plants, preferably in the morning. This will keep them well hydrated and allow the water to evaporate by the evening, thereby deterring pests that are searching for a damp environment for settlement.
How much you should water the plant and how often will vary depending on the type of crop, so educate yourself in that regard.
Apart from watering the plants, don’t forget to keep the soil healthy as the plant will derive its necessary nutrients from the soil. Learn what type of nutrients the particular crop you’re growing needs, and see to it that soil has enough of that nutrient.
14. Remove Sick Plants From Your Garden
Following simple steps can help keep your plants healthy and pest-free. However, it’s considerably difficult to nurse a sick plant back into health.
As such, if you notice a lot of sick plants in your garden and can’t cure them despite your best efforts, you should consider removing them, especially if you notice circling insects.
The more time a sick plant stays in the garden, the more pests it attracts. Furthermore, a sick plant can make nearby plants sick as well, thereby quickly escalating the problem.
This is why it’s super important to stay vigilant and take quick action if you notice a sickly plant or seedling in your raised garden.
15. Keep the Garden Clean
To keep the raised garden free of pests, we have installed physical barriers, insect traps, introducing new predatory insects, making a home for toads, and so much more.
As you can imagine, all of this stuff will slowly make the garden dirty, which might eventually attract pests into the area. As such, make it a weekly routine to clean up the garden and keep it as tidy as possible.
Here are a few things you can do to keep your garden tidy:
- Pluck out weeds along with their roots completely from the ground.
- Prune any dead branches or shoots that are lying on the soil.
- Remove dirty insect barriers and get rid of insect traps that have done their job.
- Also, wash the soil to eliminate any dirt or insect carcasses that might be lying around.
How To Spot Pests in Your Raised Garden
As we discussed earlier, some of the insects in your raised garden harm your crops, while others protect the crops and feed on the harmful insects.
That said, how do you tell the pests from the protectors?
Well, unfortunately, there’s no hard and fast rule to figure this out. You’ll need to observe the pests in your garden and do research to find out if they are here to help or harm.
I personally prefer taking a picture of the insect and then using apps like Google Lens to find out what species of insects they are. Alternatively, you could also take a picture and tally it against various online insect catalogs:
- The Bugwood Insect Images
- Agricultural Research Service Image Gallery
- Various images maintained by University entomology departments
It’s also worth remembering that not all pests will come during the day when you’re near the garden and keeping a lookout. Some pests will feast on your crops at night and leave by daybreak. In that case, to figure out which pest is damaging your garden, you can install insect traps.
Common Garden Pests and How To Find Them
I’ve put together a short guide highlighting the most common garden pests discussing how they look, how their larvae/eggs look, how they damage the plants/crops, where they usually hide, and ways to control them.
Aphids are small pear-shaped insects that may or may not have wings, depending on the particular species. The critters can also come in various colors, including black, brown, yellow, green, and even red.
The pest generally feeds on vegetable plants like cabbage, kale, and lettuce. They suck the plant nutrients resulting in deformed and stunted growth. You can usually find these critters hiding beneath a plant leaf.
To control aphids, you can encourage more predatory insects like ladybugs in your garden. You can also put up a plant cover to keep them out of the garden altogether. Neem-based insecticides also work exceptionally well at killing off aphids.
As the name suggests, whiteflies are tiny white-colored flies. They almost look like baby moths and attack plantations in groups.
The pest ideally prefers feasting on citrus fruits, but you can also find them near peppers as well as sweet potatoes. If a plant has a whitefly infestation, it’ll usually have a sticky coating on them, which is actually the excrement of the whitefly.
Similar to aphids, whiteflies also suck plant juices, which can lead to malnourishment of the plant causing yellow withered leaves.
Neem-based insecticides and sticky cards for trapping insects are most effective at controlling and stopping a whitefly infestation.
Cabbage worms are basically caterpillars that are light green and usually around 1-inch in length. As they mature, they metamorphose into white or off-white butterflies carrying around 4 black spots on their wings.
As the name implies, these pests primarily infest cabbages and other crops belonging to the cabbage family, including broccoli, turnip, cauliflower, Brussel sprouts, etc.
The critters can chew holes through the leaves and flowers of the plant. If the infestation is very severe, it can result in complete defoliation.
That said, cabbage worms are usually large, and very few of them will infect a garden at one time. As such, you can and should remove them by hand as soon as you spot them in your garden.
However, if you find a large infestation, it’s best to use an insecticide, ideally some based on bacillus thuringiensis (bt).
Like cabbage worms, cutworms are also caterpillars. They’re around 2-inches long during their larval stage and tend to curve up into a C-shape when disturbed. Depending on the species, a cutworm can be gray, brown, yellow, or green. When fully grown, a cutworm will metamorphose into a night-flying moth.
You can usually find cutworms right above the soil. They primarily target seedlings and chew through their stems. This often “cuts” and severs the seedling, hence the name.
Practicing crop rotation is one way to manage and prevent a cutworm infestation. You can also try mixing beneficial nematodes into the soil that’ll kill the cutworm eggs, thereby preventing an infestation.
Another potential fix includes placing cornmeal near vulnerable plants. The critters will take it as bait and eat it. However, since they can’t digest these granules, it’ll eventually end up killing them.
Squash bugs are inarguably one of the toughest garden pests to get under control.
A fully grown squash bug has a flat pill-shaped body and is either black or dark brown. Baby squash bugs or nymphs carry the same shape, just smaller in size and grayish. Squash bug eggs are very easy to find as they’re laid in groups and are bright yellow or bronze.
Holding true to its name, these critters mainly target squashes and other members of the squash family, including pumpkins, melons, zucchini, etc.
The squash bugs have a straw-like mouth which they use to suck nutrients out of the plant. Long enough exposure can cause yellowing of the plant and give it a dehydrated crisp texture.
The best way to control or prevent a squash bug infestation is by practicing crop rotation, installing plant cover, and using sticky tape to clear out unhatched eggs. Insecticides don’t work too well on adult bugs, but neem oil is effective at killing off the nymphs.
To keep bugs out of your raised garden, ensure the plants are healthy and remove the sick plants. Also, maintain some distance between each crop, practice intercropping & crop rotation, harvest the crops on time, and keep the garden clean.
If you still notice bugs in your garden, you can set up physical barriers, insect traps, diatomaceous earth, and mix nematodes in the soil to kill off the stubborn bugs. Other than this, you can also consider introducing predatory insects in your garden and keeping toads that will eat the bugs and keep your garden safe.