If you have ever gone into your garden in the morning and seen some of your plants cut off at the base, then you know how annoying cutworms are. Luckily, there are plenty of ways to keep cutworms at bay and protect the plants in your garden.
So, how do you get rid of cutworms on plants? One way is to make “cutworm collars” by shaping a piece of cardboard into a tube around the base of each plant. Another way is to put diatomaceous earth on the soil surrounding each plant. Keeping your garden clean and making birds feel at home can also help to keep cutworms under control.
There are even more ways to help you control cutworms in your garden, which we’ll get into shortly. First, let’s get into what cutworms are, and how you can recognize them in your garden.
What Are Cutworms?
Cutworms are not actually worms. They are caterpillars, usually less than two inches long. Cutworms will curl up into a “C” shape when resting or disturbed. They are sometimes mistaken for grubs.
Cutworms are the larvae (immature form) of certain moths, which have several life stages. First, a moth lays eggs in or near your garden.
Next, in the fall, the eggs hatch into larvae (cutworms), which wait out the winter in soil or underneath organic matter (leaves, wood, or the like).
Then, in the spring, the larvae (cutworms) come out of hibernation to feed on plants, such as the ones in your garden. Finally, the larvae become pupae, which eventually become moths to repeat the whole cycle.
Cutworms like to come out to feed in the dusk or evening hours, or on cloudy days. They prefer to stay out of the daytime sun. This makes them less of a target for predators like birds.
How Do I Know if I Have Cutworms in My Garden?
There are several ways to tell if you have cutworms in your garden. Look for some of these signs.
Plants Are Cut Off at the Stem
Seeing “decapitated” plants is the most obvious and annoying sign of cutworms in your garden. Usually, this happens to younger plants, such as ones you have just bought at the store or transplanted from your home or a greenhouse.
It will look like someone took a pair of scissors and cut off your young plants at the base. However, what really happened is that a cutworm was crawling along and found your plant. Then, it wrapped itself around the stem at the base. Finally, it chewed at the stem until it cut all the way through, killing your plant.
If you are really unlucky, a cutworm will go down a row of plants, cutting off each young plant as it goes. The only limit to the damage is how far the cutworm can go in one night!
Remember that in some cases, cutworms will also climb up a plant and feed on the fruit, buds, or leaves. There is even one variety (the glassy cutworm) that feeds on the roots of plants.
You See Cutworms or Moths in Your Garden
You may also catch cutworms red-handed in the act of climbing on or chewing on your plants. As mentioned before, you are most likely to see them in the dusk or evening hours.
Cutworms come in many colors – black is common, but you may also see green, gray, or even pink. They can be solid, or they may have stripes or spots.
Moths are the adult form of cutworms, so if you see them in your garden, there is a good chance that you have cutworms, or that you will in the future. There are some steps you can take to interrupt the life cycle of cutworms – more on this later.
You See Birds in Your Garden
Birds like to feed on cutworms, so if you see more than usual in your garden, then it could be a sign that there is a cutworm infestation.
If you can make the birds feel welcome, they might help you with your problem (more on this later).
How to Get Rid of Cutworms on Plants
There are plenty of ways to get rid of cutworms on the plants in your garden, and to keep them away.
Creating barriers to protect your plants is one possibility. You can also use natural or chemical insecticides. Planning ahead to interrupt the life cycle of the cutworms is another way to keep them under control.
Let’s get into the steps you can take to protect your harvest from cutworms.
Cutworm collars are one form of protective barrier that you can put around your plants to keep cutworms away. The classic way is to cut a piece of cardboard into square strips, perhaps 4 inches by 4 inches.
Then, take a strip and wrap it around the stem of a plant, to form a cardboard “tube”. Push the tube down about halfway into the soil to keep it in place. This will also prevent the cutworm from going under the tube.
It is possible that a cutworm could climb over or under the tube. However, it is more likely that it will keep crawling along flat ground to find easier prey, like the weeds in your garden, which are conveniently unprotected!
You can make cutworm collars out of anything that will keep the cutworms at bay. Cardboard is good because it biodegrades, but you will have to make more of them every year. Plastic bottles will also work, but you will need to cut the bottom out of them.
Another related trick takes a little more planning. First, save up cardboard tubes from empty rolls of toilet paper and paper towels. You can also ask friends and family to save them for you.
Then, cut them to the appropriate height, place them in a tray, and put some soil in the tubes to plant your seeds. Once the seeds germinate and the seedlings are large enough, you can transplant the whole thing into your garden – plant, cutworm collar and all!
This is another method that creates a protective barrier around your plants, while also acting like a natural pesticide. You can use this method together with cutworm collars, but it might be overkill.
First, buy some diatomaceous earth, which is a white powder made from rock. Then, sprinkle the diatomaceous earth to form a ring on top of the soil around your plant.
Whenever insects (including cutworms) crawl over the diatomaceous earth, it will kill them. Basically, the fine white powder is “sharp” enough to cut bugs, which then lose water through the cuts and dry up.
Diatomaceous earth is also good for killing ants – for more information, check out my article on getting rid of ants.
However, diatomaceous earth is fine for humans to handle, making it a safe pesticide (just don’t accidentally breathe a bunch of it in!)
The only problem with this method is that rain or watering may wash away the diatomaceous earth.
Leave a Bare Soil Border Around Your Garden
This is another way to create a barrier for your garden. Instead of protecting plants one at a time, you create a barrier around your entire garden all at once.
The idea is to leave a bare patch of soil around the outside of your garden. Ideally, there will be no shade on this soil, so the soil will be extremely dry.
Any cutworms that want to feed on your plants will have to cross this barren wasteland and risk dying I the sun or being eaten by birds that can see them clearly.
If you want to level-up your garden defenses, pair this method with diatomaceous earth. Simply sprinkle a line of diatomaceous earth along the top of the bare soil border on the outside of your garden.
There is one thing to keep in mind. This method will keep new cutworms from crawling into your garden. However, the cutworms that are already in your garden will not be able to leave. Furthermore, moths will still be able to fly into your garden and lay their eggs.
Make the Birds Feel Welcome
This is a good, simple method that won’t take much time, and it can also be paired with some of the others mentioned earlier. It is also a natural pesticide, so you won’t have to worry about chemicals on your plants.
Simply put out a bird feeder and a bird bath, and make the birds feel welcome. They might show up for the free sunflower seeds, but they will stay for the cutworms and other garden pests.
You could even put a bird bath at each corner of your garden, which has a nice decorative effect. If the birds see any invading cutworms, they will swoop down and do your dirty work for you.
Add Some Beneficial Nematodes
Beneficial nematodes are tiny creatures that look like worms. They are parasites to many bugs, including cutworms. Buy some of these and release them in your garden to help control cutworms without chemical pesticides.
Clean Up Your Garden
You were probably going to do this anyway, but if you do it correctly, you can prevent much of the carnage that cutworms will cause.
After the fall harvest, take any debris and remove it from the garden. Either burn it, or put it in a compost pile far away from the garden. Just remember that if there are already eggs or larvae in your garden, then a compost pile gives them a good place to wait out the winter.
If you want to compost the waste, a better idea is to have two different compost piles. Then, you can alternate the years that you use each pile.
The cutworms that over-winter in the unused compost pile will need to leave in the spring to find food. That means you aren’t putting so many cutworms back into your garden.
Till Up Your Garden Soil
Even though you cleaned up your garden in the fall, make sure to do it again in the spring. Then, till up the soil, either by digging or using a rototiller. If you don’t have a machine or don’t want to do it yourself, check out my article on the price of rototilling.
Leave the soil unplanted for a while, and give the birds a shot at any cutworms that you may have unearthed.
Plant Later in the Spring
If you can, wait a little longer to plant in the spring. If you start your own plants from seeds, keep them indoors or in the greenhouse a little longer.
That way, the cutworms may starve before they get a chance to feed on your plants. At the very least, some of them will give up on your garden and move to greener pastures.
Add Sacrificial Plants
You can also add sacrificial plants on the borders of your garden that the cutworms can eat. Maybe you could plant some extra seedlings that you raised, or plants that you don’t really care about, to keep the cutworms busy.
Declare War on Cutworms
This method is barbaric, and not very efficient. Here is how it works: you go out into your garden at night with a flashlight and find cutworms.
Then, you pick them up off the ground or remove them from your plants. Finally, you … put them between a rock and a hard place (usually another rock).
It might not seem like a few cutworms matter, but each one of them could lay many eggs in a season.
Buy Chemical Solutions Off the Shelf
There are countless chemical pesticides that you can buy online or at a garden center. However, these will end up in your soil, in your plants or on your food. I would do this only as a last resort.
By now, you know what cutworms are, what they look like, and how to recognize the signs that they have taken a liking to your garden. You also know about many good methods to prevent cutworms from hurting or killing your plants.
I hope you found this article helpful. If you have any questions or tips about dealing with cutworms, please leave them in the comments below.