Garden 
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The short answer: to get rid of cutworms, put a protective collar around each seedling stem — a cardboard tube, cut paper cup, or foil wrap pushed an inch into the soil — so the caterpillars cannot sever the stem, then handpick them at night or by digging near damaged plants, and treat with Bt (Bacillus thuringiensis) or a diatomaceous earth barrier for larger outbreaks. Before planting, clear weeds and turn the soil two to three weeks ahead to expose and destroy the overwintering larvae. Collars plus nighttime handpicking protect seedlings through their most vulnerable weeks.
Cutworms are fat, dull gray or brown caterpillars, up to about 2 inches long, that curl into a tight C when disturbed. They are the larvae of several night-flying moths and are notorious for one thing: chewing through the stems of young seedlings and transplants right at the soil line, felling a whole plant in a single night. We do not test products first-hand; this guidance reflects horticultural and university-extension consensus, described in how we rank.
Confirm it is cutworms
Cutworm damage has an unmistakable signature:
- Seedlings cut off at or just below the soil line, often toppled and left lying — not eaten, just severed.
- Whole young transplants gone overnight, with the damage appearing suddenly.
- Fat, greasy-looking C-curled caterpillars found 1 to 2 inches deep in the soil within a few inches of the damage.
- No slime trails (which would indicate snails or slugs) and no daytime feeding.
The University of Minnesota Extension notes that cutworms are most damaging in spring on newly set transplants and in gardens broken from sod or left weedy the previous year. If seedlings are being eaten rather than cleanly cut, or you see slime, suspect snails, slugs, or other caterpillars instead — see how to get rid of snails.
The Cutworm Life Cycle Behind Spring Attacks
The moths that produce cutworms lay their eggs in late summer and fall, often on grasses, weeds, and low plant debris. The larvae hatch and overwinter in the soil, then become active and hungry in spring — precisely when gardeners are setting out tender seedlings. They feed at night and hide just below the surface by day. Because they overwinter in the top few inches of soil, cultivation and weed removal before planting are powerful preventives, and a bed newly turned from lawn or a weedy patch is the highest-risk situation of all.
Collars: The Best Cutworm Protection
A stem collar is a simple physical barrier that stops the cutworm from wrapping around a stem to cut it. This is the standard, and most effective, home defense.
- Make collars from cardboard tubes (toilet-paper or paper-towel rolls cut into 3 to 4 inch lengths), cut paper or plastic cups with the bottoms removed, or strips of aluminum foil.
- Place one around each transplant at planting time, pushing it about an inch into the soil so the cutworm cannot tunnel under, and leaving 2 to 3 inches above ground.
- Leave a little space between the collar and the stem so it does not constrict as the plant grows.
- Keep collars on for the first few weeks until stems thicken past the vulnerable stage.
Handpicking and digging
Because cutworms hide by day and feed at night, two removal tactics work well. In the evening, patrol with a flashlight and pick off caterpillars feeding at the soil line, dropping them in soapy water. By day, when you find a freshly cut seedling, scratch through the top inch or two of soil within a few inches of the stem and you will usually find the C-curled culprit; remove and destroy it. A few nights of patrolling early in the season, when populations and damage peak, makes a real difference.
Baits, Bt, and barriers
| Control | How it works | How to use it |
|---|---|---|
| Bt (Bacillus thuringiensis kurstaki) | Bacterium that kills caterpillars that eat it; harmless to people, pets, beneficials | Apply to soil surface and stems in the evening; reapply after rain |
| Diatomaceous earth ring | Abrades and dehydrates crossing caterpillars | Ring seedlings; reapply after any moisture; keep off flowers |
| Cornmeal or bran bait (with Bt or spinosad) | Attracts and delivers control at the surface | Scatter near plants at dusk |
| Beneficial nematodes | Parasitize larvae in the soil | Drench moist soil in the evening per label |
Bt and spinosad are the low-toxicity chemical options and are effective on the actively feeding larvae; diatomaceous earth and beneficial nematodes add soil-level pressure. For heavier or broader infestations, a labeled soil-active insecticide is an option; see best yard insect killer. For a related soil-dwelling grub problem, see how to get rid of grubs.
Preventing cutworms next season
- Turn the soil and clear weeds two to three weeks before planting, exposing overwintering larvae to weather and predators — the most powerful preventive.
- Delay transplanting slightly where possible, since older, sturdier transplants resist cutting better than tiny ones.
- Keep the garden and its edges weed-free in late summer and fall, when the moths lay eggs.
- Encourage predators — birds, ground beetles, and parasitic wasps — by avoiding broad-spectrum sprays.
- Use collars routinely on all new transplants in beds with a cutworm history.
With collars on your seedlings and the soil cleared before planting, cutworms rarely get a foothold. For other soil and vegetable-garden pests see how to get rid of tomato hornworms, and browse the full pest and weed control hub.