Recently I’ve been finding rapidly gaping holes in my newly planted spinach, kale, cauliflower and broccoli leaves (a big “nuh-uh”). As I’ve been focusing on organic and sustainable gardening practices, I’ve been avoiding using any chemicals or toxic sprays, but this means my garden is indeed left wide open to your not-so-friendly neighbourhood bugs and pests.
SO, I’ve been on the search for natural ways to keep caterpillars and butterflies away from my garden, and here are some of the wonderful methods I’ve found (and have started using on my garden – in particular, the intercropping method).
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Natural Controls to Keep Caterpillars Away from the Garden
Before we start, it’s important you identify specifically which caterpillars you’re dealing with, because some methods will get rid of certain types of caterpillars, but will be ineffective against others. The methods below cover some of the most common caterpillars and what you can do to remove them from your garden.
Cutworms are found to live below the surface of the soil and will eat through seedlings’ stems during the night. To help prevent this, using plastic cups or toilet paper rolls by cutting them into 2 inch (5.1 cm) strips and placing them around tender young plants can help protect them from these pests.
Another option is to use sterile soil to start your seedlings (I bought fresh soil from our local nursery). This helps prevent any pests that live through the winter and eat your baby plants.
Tomato hornworms tend to target tomato plants (hence the name) and will strip them of their leaves in less than a day (they work fast!). They’re easily recognisable by the large spike on their rear end. Picking them off by hand (I always use garden gloves for this) works really well at getting rid of these caterpillars (it’s just tedious). After you’ve picked them off, drop the hornworms into a jar that contains soapy water, which will kill them. Otherwise just use your shoe to squish them.
If these methods are too gruesome for you (don’t worry, they were for me), instead dump any caterpillars you find into the garbage bin.
Swallowtail Butterfly Caterpillars
Favourite foliage for these caterpillars include dill, parsley, fennel, cilantro, carrot, and parsnip. You can recognise these insects by their white and yellow stripes, and their fat, bright green bodies. Do not kill them. It’s advised that you handpick these caterpillars and move them to a patch of Queen Anne’s lace (a.k.a wild carrot, it’s a wildflower herb) or to another location away from the garden.
The swallowtail butterfly caterpillars (there are a few different types), from right to left; black swallowtail caterpillar (source), orchard swallowtail butterfly caterpillar (source), Blue Mountain swallowtail caterpillar (source), and the spicebush swallowtail caterpillar (source)
Alternatively, planting extra dill, parsley, and fennel for the butterflies to eat is another way to keep these little guys away, and ensuring there is enough to go around.
Cabbage Moth Caterpillars
Covering your garden and plants with translucent fabric (so as to allow light to still pass through) or by using polypropylene row covers are both good ways to protect cabbages, mustard plants, swede, or rapeseed from falling prey to cabbage moths and other pests.
Cabbage moth caterpillars; we had these guys all over our kale garden, broccoli and cauliflower plants. The top right pic is of an empty cocoon of one of the caterpillars that hatched
Pre-made row covers can be bought at garden centres (I bought mine from our local nursery), but you can also make your own! All you have to do is stick hoops into the ground and cover them with either perforated plastic or fabric sheeting. These materials should let in both sun and air but also serve as a barrier for most bugs. TIP: It’s a good idea to weigh down row covers on one end using bricks, wood planks, or other heavy materials (prevents it blowing open and allowing bugs in).
NOTE: Always wear good gardening gloves when hand-picking caterpillars. Some species will inflict a painful sting.
Check Plants Frequently for Eggs
Rake/sweep up and remove all of the fallen leaves and debris around your plants each autumn/fall. This will help keep the caterpillar population under control (in case there are any eggs hidden away amongst them all). Also, check the leaves on the plants for caterpillar eggs – regardless of the type of caterpillar you’re dealing with – throughout the growing season (pay particular attention to the underside of leaves). Ensure you check both tops and bottoms of the leaves carefully and thoroughly.
I found some cabbage moth eggs on our kale plants (some moths have managed to get through our netting). As I was de-caterpillaring our garden, I found one of the cabbage moth caterpillars sitting over the eggs (as you can see on the right)
When you find any eggs, pinch off the egg or snip off the leaf and throw it in the garbage.
Encourage Birds and Wildlife to Your Garden
This is a useful long-term strategy (you’ll want to apply some of the other methods in the short-term until you’ve established a healthy range of insects and wildlife in your area) to help reduce caterpillars and other pest infestations. Beneficial insects to foster and that prey on leaf-eating caterpillars include chalcid, brachonid and ichneumon wasps (these aren’t the kinds of wasps that sting people). To attract them, grow plants such as carrots (Daucus carota var. sativus) and parsley (Petroselinum crispum) and leave them to flower. Encourage caterpillar-eating birds like chickadees, nuthatches, orioles and warblers into your area by bringing in a birdbath or fountain, or even a bird feeder (just place a cone around it to keep out hungry squirrels) and leave an area of your garden to grow a little wild, which provides cover and nesting sites.
Ducks and chickens also eat caterpillars, and if you the space they can add a layer of bug control and provide tasty eggs!
Heavily Intercrop Your Garden
Intercropping, or companion planting – growing plants singly or together in a given area to repel insects, fight disease, or promote the growth of another plant – is a technique many gardeners have used for generations (and is a wonderful sustainable gardening technique!).
Creating effective crop combinations helps repel insects by using plants’ natural fragrance, oils, compounds, and colours to keep away pests. See what works for you. Try some of the combinations below and develop your own opinion based on what you observe and any successes that occur. Keep a record of what works and let others know! (Share your success below with us all!)
Placing mugwort, sage, thyme, rosemary, and/or peppermint (be careful with mint; mint plants are quite invasive in most areas and should be planted in containers rather than in the ground) around affected plants may help deter caterpillars. These herbs are strongly scented so will help disguise these foods so that the butterflies/caterpillars head elsewhere in search of food.
Here is a list (I found from Harvest to Table) of companion plantings aimed at deterring pests from the garden. There are also companion plantings you can try to attract beneficial insects to your garden too (but I haven’t listed them here – if you’d like a post about that, share with me in the comments).
Insects deterred: Most insects
Plant near: Sunflower, plant around the garden
Insects deterred: Flies and mosquitoes
Plant near: Tomato; avoid planting near rue
Insects deterred: Tomato worn, cabbageworms
Plant near: Tomato, cabbage family crops, strawberry
Insects deterred: Asparagus beetles, tomato hornworms, most insects
Plant near: All vegetables and herbs
Insects deterred: Flea beetles, spittle bugs, ants, Japanese beetles, weevils
Plant near: All vegetables
Insects deterred: White cabbage butterfly
Plant near: Leek, tomato, cabbage, cauliflower, bush bean
Insects deterred: Most insects, nematodes
Plant near: Tomato; avoid planting near lettuce
Plant: Dead Nettle
Insects deterred: Potato bugs
Plant near: Potato
Insects deterred: Colorado potato beetle
Plant near: Green bean, lettuce
Plant: Flax (Linnum usitatissimum)
Insects deterred: Potato bugs
Plant near: Potato, carrot
Insects deterred: Japanese beetle, aphids, other insects and blight
Plant near: Tomato, eggplant, cabbage family plants; avoid planting near peas, beans, and other legumes
Insects deterred: Cabbageworms, corn earworms, Japanese beetles, most insects
Plant near: Interplant with vegetables, especially cabbage
Insects deterred: Potato bug
Plant near: Potato, horseradish needs a permanent home
Insects deterred: Most insects
Insects deterred: Cabbage moth
Plant near: Cabbage family, orchards, grapevines; avoid planting near radishes
Insects deterred: Nearly all insects including Mexican bean beetles and nematodes
Plant near: Potato, tomato, pepper, eggplant, roses
Insects deterred: Cabbage moth and ants
Plant near: Cabbage, tomato
Plant: Mole plant (Euphorbia lathyrus)
Insects deterred: Moles, gophers, mice
Plant near: Space around the garden every 5 feet (1.5 metres) as a barrier
Insects deterred: Aphids, squash bugs, striped pumpkin beetles, whiteflies
Plant near: Beans, cabbage family plants, cucumber
Plant: Onion family
Insects deterred: Most pests, Colorado potato beetles, carrot rust flies
Plant near: Most vegetables except peas, beans, sage
Insects deterred: Bean pests, Mexican bean beetles, potato bugs, squash bugs
Plant near: Beans, squash, potato
Plant: Pot Marigold
Insects deterred: Asparagus beetles, tomato worms, general garden pests
Plant near: Asparagus, tomato, most vegetables
Insects deterred: White cabbage butterfly
Plant near: Cabbage
Insects deterred: Cucumber beetles, squash borers
Plant near: Beans, carrot, cucumber, kohlrabi, parsnip, onion, squash
Insects deterred: Cabbage moth, bean beetle, carrot fly
Plant near: Beans, cabbage family plants, carrot
Insects deterred: Japanese beetle
Plant near: Avoid skin contact; do not plant near cabbage family plants
Insects deterred: Cabbage moth, carrot fly
Plant near: Plant with perennial vegetables; avoid planting with cucumbers and rue
Insects deterred: Carrot fly
Plant near: Carrot family plants
Plant: Southernwood (Artemisia abrotanum)
Insects deterred: Cabbage moth, black aphids
Plant near: Cabbage family plants or make a southernwood-water solution to spray cabbage
Plant: Summer Savory
Insects deterred: Bean beetles
Plant near: Beans, onion
Insects deterred: Flying insects, Japanese beetles, striped cucumber beetles, squash bugs, ants
Plant near: Squash, potato; avoid planting near collard
Insects deterred: Cabbage worm
Plant near: Eggplant, cabbage, potato, tomato, almost all vegetables and herbs
Insects deterred: Asparagus beetle
Plant near: Asparagus, dill, borage
Plant: Wormwood (Artemisia absinthium)
Insects deterred: Carrot fly, white cabbage butterfly, black flea beetle
Plant near: Do not plant wormwood in the vegetable garden, but leaves used to make a spray will deter insects.
DIY Chili Spray to Control Caterpillars
If your garden is infested by caterpillars, try this recipe (I found originally from SFGate):
- Grind 3 1/2 oz dried chilies in a food processor.
- Add the powder to 1/2 gallon boiling water.
- Boil mixture for 5 minutes.
- Add 1/2 gallon cold water and 2-3 drops of liquid soap.
- Allow mixture to cool.
- Test solution on a leaf and wait 24 hours. If the plant shows no reaction, spray the chili mixture on the caterpillars every evening.
Neem oil and bacterial sprays work really well as natural pesticides. Neem tree seeds have natural insecticidal properties, and works extremely well on most insects infestations. BT, or Bacillus thuringiensis, is an excellent organic bacterial spray for keeping caterpillars out of the yard. Ensure you carefully read and follow the manufacturer’s directions for mixing and applying pesticides, and ensure you only spray neem oil after dusk when the bees are no longer out, as it’s toxic to them.
Neem Oil Spray
I’ve been using this spray on my plants to help keep caterpillars and aphids at bay (it’s been really effective when I’ve remembered to do it ;). I found the recipe originally from Greener Ideal.
- To make 1 L of this general-purpose neem oil spray, mix 5 mL neem oil, 2 mL of liquid soap (non detergent and natural if possible – I have a soap recipe here you can make, or even just use a natural liquid castile soap!) and 1 L of water.
- Add the soap to the water first and then slowly stir in the neem oil. Adding soap may seem strange, but the reason we do it is because neem oil doesn’t readily mix with water, so adding an emulsifier like a mild liquid soap helps to mix it together, so the oil and water aren’t separated (otherwise you’ll basically be spraying water on your plants, with neem oil only coming out at the end).
- Pour the mixture into a spray bottle and it’s good to go! You’ll need to use the mix within 8 hours as after that the ingredients begin to break down.
More natural gardening tips:
How To Get Rid Of An Aphid Infestation Naturally
How To Begin a Sustainable Veggie Garden
Natural Ways To Keep Snails & Slugs Away From Your Garden
How To Regrow Veggies From Scraps
Growing My Own Veggie Garden!
Food Waste: How to Reduce It + DIY Composting
Lots of love,
How to Keep Caterpillars Out of the Garden. (Updated: March 29, 2019). WikiHow. Retrieved from https://www.wikihow.com/Keep-Caterpillars-Out-of-the-Garden
Albert, Steve. Insect-Deterrent Plants For The Vegetable Garden. Harvest To Table. Retrieved from https://harvesttotable.com/insect-deterrent_plants/
Green, Jenny. (Updated: December 14, 2018). How to Get Rid of Caterpillars Without Pesticides on Plants. SFGate. Retrieved from https://homeguides.sfgate.com/rid-caterpillars-pesticides-plants-29475.html