8 Ways To Rid Your Vegetable Garden Of Caterpillars

Caterpillars are curious creatures in many ways. Yet for anyone who grows their own food, they can be a huge pest. If left unchecked, they can strip leaves bare and undo months of careful growth in a matter of days. Brassicas, such as broccoli and cauliflower, are especially vulnerable, but most of your crops can be at risk, including tomatoes from the notorious hornworm.

As someone who owns their own gardening business, caterpillars are always something I need to consider. Yet, without caterpillars, you wouldn't have beautiful butterflies and vital moths to pollinate your crops. Therefore, you need to know the best strategies to keep your crops healthy while appreciating the importance of garden biodiversity. It's a delicate balance.

That's what I'm here to help you with. You don't want (and it's practically impossible) to eradicate caterpillars completely, but these eight tips will show you how to intervene to save your crops. This will allow those caterpillars to focus on other plants that you're less fussy about. These tips can protect your plants without damaging the ecosystem, allowing your crops to grow fully for bountiful harvests.

You may have immediately recoiled in disgust at reading the headline to this tip, but it is direct and effective. You won't need to worry about any equipment, buying anything, or damaging another life. Consistency is key here, as you'll want to frequently check on your plants to remove them. Caterpillars are often found on the underside of leaves, so make sure to check your plant properly. You'll most likely already see signs of damage to confirm their presence. Simply remove them by hand. Most of them are harmless, but a few are poisonous, so it's best to use gloves. 

What you do with them next is up to you. If you're protecting a specific crop, you may want to move the caterpillar somewhere else in your garden or further afield. If you're dealing with a consistent issue and are growing a wide range of fruit and vegetables, dropping them in soapy water is a quick and humane way of killing them. If you are consistent with doing this, they'll never develop into a big problem, and you can cope with a little leaf damage. It's a good idea to check your plants regularly for signs of issues and other pests. Therefore, picking off caterpillars can become a part of your daily schedule.

If you're bringing out the heavy artillery, you want to do it in the right way. Pesticides, often justifiably, have a bad reputation for their wider ecological impact. However, there are now many that can target a specific issue without wider harm. Bacillus thuringiensis (Bt) is such a pesticide. This biological control will disrupt a caterpillar's digestive system, meaning they stop feeding and die. The crucial part here is that Bt will only affect a narrow range of leaf-eating larvae. Your beneficial insects, including pollinators such as bees and butterflies, won't be affected.

It's easy to buy and not too expensive, but it should still be used with caution. It can come in ready-to-use spray bottles or in a concentrated mixture. It's best to apply it while it's dry and ensure you're spraying the underside of leaves and not just the top. It's highly effective and best used when you're dealing with a significant issue. After you get the caterpillar population under control, you can then look to utilize less dramatic methods, including handpicking and the rest of the tips to follow.

Garlic and chili pepper are at the opposite end of the spectrum to the biological control above, as it's a gentler approach meant to deter caterpillars rather than kill them. This method simply works by making the leaves unappealing, as the strong scents and tastes of garlic and chili can put them off. The easiest way to do this is by mixing garlic granules and/or chili powder into water. You can use fresh chilies and garlic, but you'd need to steep them in the liquid longer to ensure you get the desired effect.

Adding a touch of dish soap is a good idea to make the solution stickier so it doesn't immediately run off the leaves. Cover both sides of the leaves and let the cocktail work its magic. This is a natural and non-aggressive solution that is best used in conjunction with other methods, such as handpicking. Rain washes this spray away quite easily, so it's likely you'd need to reapply it fairly often.

Neem oil is a great tool for gardeners to have as it has a few different uses, and it can even be used to protect your kitchen from any wandering ants. One use is pest control: It can reduce a soft-bodied insect's ability to feed. This includes small caterpillar larvae, but it also works for the likes of aphids and whiteflies, which can also be a nuisance. Neem oil works more gradually than other solutions; you'll first coat the leaves in neem oil using a spray, and then it works once ingested. This will gradually reduce the population and the damage to your crops.

Application is straightforward, because neem oil often comes in a spray bottle, but you can also buy a concentrated solution. As with the Bt above, spray it evenly over your plants, making sure not to miss out on the underside of your leaves. You may need repeated applications to get the desired results. Neem oil can be dangerous to beneficial insects, so it's best to be cautious and not overspray. Apply it early in the morning or later in the evening when pollinators are less active. It's best to see it as a targeted solution when you're struggling to keep your caterpillars under control.

Caterpillars can't eat what they can't get to. Installing a physical barrier is an effective way to stop caterpillars from eating and laying eggs on your crops. The best physical barrier depends on what plant you're trying to protect, but usually, a fine mesh cover will do the job. This is especially useful for tall plants such as tomatoes, as you can drape the netting over the whole plant and tie it shut at the bottom.

For plants closer to the ground, you may wish to opt for a small structure such as a compact polytunnel. This can protect the plant without the mesh physically touching it. There are other solutions here, such as mini greenhouses or a garden cloche for seedlings. All these will create that physical barrier while still allowing light, air, and rain to pass through. I personally don't like doing this for the simple fact that it looks ugly, but there is no doubt it's effective, especially for vulnerable plants.

Even with these solutions, it's good to remember pests can be, well, pests. They will get through the smallest gaps, and there may have been existing eggs on the leaves or in the soil that you may have missed. Therefore, you still want to check on your barrier intermittently. Once you're confident you have the right setup, this requires very little ongoing care compared to other methods.

When you have a biodiverse garden, everything seems to work in perfect harmony. It's possible that caterpillars are running riot in your garden as they aren't being targeted by natural predators. There are two cute killers that you want to entice to your garden. The first are birds. There are many common species that actively feed on caterpillars, and, therefore, you don't need to worry about attracting a certain type. Adding feeders, fresh water sources, and safe nesting spots is the best way to do this. The biggest downside to look out for here is that birds eat berries, so if you're growing the likes of strawberries, you'll want to keep them protected.

The other predator you need to encourage may surprise you: ladybugs. They can feed on small caterpillar larvae, helping to reduce your numbers further. Ladybugs are also prolific killers of aphids and other small pests. If you see an abundance of them in your garden, you should be very happy. Ladybugs are most attracted to open-faced pollen-rich plants, such as sunflowers, dill, and yarrow. When not feeding on garden pests, they are usually busy pollinating your plants — a true gardener's friend. Of course, this isn't an instant fix, and you can't make your garden a bird and ladybug paradise overnight. Yet encouraging these creatures gives you a more sustainable and hands-off way to reduce caterpillar numbers.

Companion planting is a great way to ensure that specific plants thrive. It's easy to make mistakes with companion planting, but when done the right way, it can be a useful tool when combined with other methods. Depending on your companion of choice, the aim here is to either confuse a caterpillar or direct it away from your main crops. To confuse them, you want a plant that has a strong smell. This means it can mask another smell they may otherwise be attracted to. Great candidates here include strong herbs such as mint, sage, and thyme. Essentially, you're hoping a butterfly or moth won't catch the scent of a target plant.

The way to direct it away from your main crops is by having a sacrificial plant. For example, lettuce is perhaps the easiest crop to grow. You can allow your lettuce to be your home for a caterpillar without bemoaning the time and effort you took to grow it. While you may lose a few sacrificial plants, you protect the crops that take a lot more effort to grow, such as peppers. As with a lot of the solutions here, this isn't a magic fix but can be powerful when used with other methods. Unless you have an infestation you need to address immediately, these solutions can give you a well-rounded and natural caterpillar strategy.

Along with picking off caterpillars, another simple solution is to wipe the eggs off before they even have a chance to hatch. They are easy to miss if you're not sure what you're looking for. Yet once you get comfortable spotting them, wiping them away can become a great habit. These eggs can come in several different colors, but you can find most in a tight cluster, with dozens of eggs grouped together. You can wipe them off with your fingers if you're brave, but a cloth or soft brush will also do the job.

It's best to crush the eggs to stop them from hatching or otherwise dispose of them. Of course, this will tackle the problem before it even begins. Consistency is key here as you'll want to check at least once every couple of days throughout the summer. As with all these tips, it is good to remember that caterpillars are important. While they can be a pest at this stage, the butterflies and moths are beneficial insects and excellent pollinators. Therefore, a few caterpillars aren't a big issue, and you shouldn't look to eradicate them completely. Instead, by using these tips, you can help to keep caterpillar numbers under control and make sure they aren't munching on your most valuable crops.