General gardening topics

10 Organic ways to stop caterpillars eating your plants

Last updated on April 24th, 2022

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If you’ve ever thought a caterpillar wasn’t a threat to your garden, you were wrong. Caterpillars might seem cute, but while they prepare to turn into a butterfly, they can destroy an entire plant whilst finding energy. A single caterpillar can grow exponentially in a given week, surviving off your garden plants. In fact, if you don’t check your garden daily, you might not notice the damage to your tomatoes or cabbages and many other plants until it’s too late. 

So, what can you do to get rid of these critters before they eat your entire plant, but without using pesticides or chemicals? Below are 10 organic ways to resolve your pesky caterpillar problem. 

Before we get into it, some of the measures include mixing organic sprays. With all sprays with highly recommend spraying a small part of the plant first and leaving it for a couple of days. If everything is fine and the plant has not been affected negatively, then spray the rest of the plant.

Organic methods you can use to stop caterpillars

1. Spray your plants with soap and water

Start with regular soap and water. If you dissolve organic liquid soap in a container of warm water and then spray it on the affected plants it will make the surface of your plants slippery so that they won’t be able to walk on it and eat your plants. Don’t worry, it won’t harm them, just force them to look elsewhere for nourishment.

2. Bacillus thuringiensis 

This is a natural bacteria that exist in your soil. It has a protein in it that, to soft pests like caterpillars, is highly toxic. This will paralyse their digestive system and force them to stop eating. It is toxic to caterpillars, but for humans, good insects and animals it is completely safe. Don’t worry about using it in your garden with produce; just wash your produce before you eat it.

*Tip: Make sure you get Bacillus thuringiensis that is organic and labelled thusly by the Organic Materials Research Institute.

3. Make a garlic and pepper spray

You can make a potent mixture, not just for your dinner, but for pests. A mixture of 1 tablespoon of dried red pepper flakes with 1 whole onion (that has been minced), 1 teaspoon of soap and one gallon of water. These contents should be blended together well and after you have done this, let the mixture remain for 24 hours, to really allow the contents to bind with one another. After that, you can fill a spray bottle and tackle any hungry caterpillars. 

*Tip: This mixture works well on worms or aphids as well, so you can make a large mixture and save it for any further pest problems throughout the season. 

4. Mix some chilli spray

You can make a similar mixture to the one above, but one that is a chilli spray, to ward caterpillars off as well. On the stove, boil ½ gallon of water with 3.5 ounces of dried ground chillies for five minutes. Remove it from heat and mix ½ gallon of cold water with 3 drops of organic liquid soap. Stir the mixture and allow it to cool for a few minutes. 

*Tip: If using this method you should do a test application beforehand. Place a small amount of a leaf (or two) of the affected plants. If there are no adverse effects on your plants within 24 hours, then you can fill a spray bottle and apply it as needed to the entire plant. 

5. Make a spray using vinegar

Vinegar will naturally deter many pests, caterpillars included and a mixture of 4 litres of water with 2 tablespoons of vinegar is all you need. Spray it onto the affected plants and it will keep the caterpillars away. 

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*Tip: If you have a snail or slug problem, spray vinegar directly onto the pests and in its raw form it will kill them.

6. Neem oil – use with care

Neem oil acts as a natural pesticide to ward off caterpillars and similar tomato hornworms. This method should be used in small amounts because it can prove harmful to beneficial bugs as well. For this method, dilute a very small amount of neem oil, no more than 2 ounces, into a gallon of water. Mix it well and apply it to the affected in the late afternoon. 

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7. Encourage birds into your garden

Another option is to bring a natural predator into the mix, figuratively. Birds eat caterpillars, so you can place a bird feeder or birdhouse near the affected plants and let the birds naturally reduce your caterpillar population. 

You can also introduce chickens into your garden. They will wander about and eat all the caterpillars for you. 

Learn more about how to attract birds into your garden from our article here

*Warning: If the caterpillar problem is on your fruit trees, avoid this method because it draws more birds to your fruit too. 

Choosing the right bird box for the right type of birds

8. Grow plants that repel caterpillars

Just as you can introduce birds as natural predators, you can introduce new plants that naturally repel caterpillars. These include sage, mugwort, peppermint and lavender. All of these will strongly repel caterpillars. Of course, with this method you also get the benefit of delightfully smelling plants and some that can even be used when cooking. 

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9. Burlap

You can wrap your trunks with burlap and it will encourage the caterpillars to crawl under the burlap for shade during the heat of the day. This is, in effect, a trap because the purpose is to give a large infestation of caterpillars a place to hide when it is hot, and then once they are hidden, you can move them or kill them by hand. 

10. Cover your plants with fine mesh netting

Finally, you can cover your plants with a thin mesh to prevent caterpillars from getting onto them, or more importantly stop the butterflies laying their eggs on your plants. This prevents the bugs from making direct contact, eating, or subsequently laying eggs which in turn creates more caterpillars. 

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While these organic measures will help remove the caterpillars, it is in your best interest to keep them out. Preventative measures include keeping an eye out for eggs and disposing of them when you find them, making sure you don’t have lights in the garden that encourage moths to land and lay eggs, and making sure any infestation is done away with immediately.

Last update on 2022-03-17 / Affiliate links / Images from Amazon Product Advertising API

Welcome to my site, my name is John and I have been lucky enough to work in horticultural nurseries for over 15 years in the UK. As the founder and editor as well as researcher, I have a City & Guilds Horticultural Qualifications which I proudly display on our About us page. I now work full time on this website where I review the very best gardening products and tools and write reliable gardening guides. Behind this site is an actual real person who has worked and has experience with the types of products we review as well as years of knowledge on the topics we cover from actual experience. You can reach out to me at john@pyracantha.co.uk

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