Do mothballs, ammonia, or ultrasonic repellents work for groundhogs?
Updated
Direct answer
Most of the time, no. Mothballs, ammonia, and ultrasonic devices rarely drive groundhogs away for good because burrows vent, have multiple exits, odors dissipate, sound doesn’t penetrate soil well, and groundhogs habituate quickly. The reliable fix is proper burrow repair plus exclusion (confirm inactive or remove the animal → collapse/pack tunnels → install a buried barrier to prevent re-digging).
Quick decision
| Method | Works long-term? | Best use | Notes / risks |
|---|---|---|---|
| Mothballs | Usually no | Not recommended | Odor disperses; misuse can be hazardous to people, pets, and wildlife. |
| Ammonia | Usually no | Not recommended | Fumes dissipate; irritation/safety concerns; not a durable solution. |
| Ultrasonic devices | Rarely outdoors | Limited experiments | Coverage is poor outdoors; soil/obstacles block sound; animals habituate. |
| Burrow repair + exclusion | Yes (most reliable) | Permanent prevention | Requires correct timing and a buried barrier to prevent re-entry. |
Why these repellents usually fail
- Burrows vent and have multiple exits: odors/fumes dissipate instead of saturating the tunnel system.
- Habituation: if food and shelter remain, groundhogs tolerate the annoyance and keep returning.
- Outdoor conditions: wind, moisture, and distance reduce odor and sound quickly.
- Access remains: without repairing tunnels and blocking re-digging, you’re not removing the “why” the spot stays attractive.
What works instead
1) Confirm whether the burrow is active
- Fresh soil, tracks, new chew marks, or reopened entrances = likely active.
- Lightly “plug” an entrance and check within 24 hours for re-opening.
2) If active, resolve the animal issue first
- Use legal humane removal methods or a wildlife-control professional.
- Don’t trap an animal inside by filling an active burrow.
3) Collapse and compact the tunnel system
- Don’t just fill the entrance—collapse the run where practical.
- Backfill in layers and compact each layer to prevent settling and re-opening.
4) Install exclusion to prevent re-digging
- Use heavy-gauge hardware cloth as a buried barrier around vulnerable edges.
- Flare the barrier outward (an “L-footer”) to stop digging at the same spot.
Common mistakes
- Filling an active burrow: can trap an animal or force a new exit.
- Only stuffing the entrance: leaves tunnels intact and likely to reopen.
- Relying on repellents alone: doesn’t remove access to shelter.
- Skipping exclusion: invites re-digging in the same area.
FAQ
Do mothballs get rid of groundhogs?
Usually no. Groundhogs often tolerate strong odors, and burrows vent to the outside, so the smell disperses. Mothballs can also be a hazard to people, pets, and wildlife if misused.
Will pouring ammonia in a groundhog hole work?
It rarely solves the problem long-term. Burrows have multiple chambers and exits, so fumes dissipate. It can also create safety risks (irritation, harmful vapors) and isn’t a reliable control method.
Do ultrasonic pest repellents work outdoors?
Most don’t work well for groundhogs in open yards. Sound disperses and is blocked by soil, vegetation, distance, and obstacles. Animals also habituate, especially if the area still provides food and shelter.
What actually works to stop groundhogs from coming back?
The reliable approach is exclusion + proper burrow repair: confirm activity status, remove/resolve the animal issue if active, collapse and compact the tunnel system, then install a buried barrier so the spot can’t be re-dug.
Should I fill a hole while the groundhog is still using it?
No. First verify it’s inactive (no fresh digging, tracks, or reopened entrances). If it’s active, use legal humane removal or a wildlife pro, then repair and exclude.
Related pages
- Do mothballs, ammonia, or ultrasonic repellents work for groundhogs?Do mothballs, ammonia, and ultrasonic devices actually work for groundhogs? Learn why these repellents usually fail, what can be risky, and what works instead (exclusion + proper backfill).
- How to install an L-footer hardware cloth barrier to stop groundhogsA step-by-step guide to installing an L-footer (buried hardware cloth) to prevent groundhogs from digging under decks, sheds, and fences—plus common mistakes to avoid.
- How to tell if a groundhog burrow is activeLearn the simplest signs a groundhog burrow is currently in use, how to check safely, and when it’s safe to fill and exclude the hole.
- Are groundhogs dangerous to people or pets?Learn whether groundhogs pose a risk to people, dogs, or cats, when they can become dangerous, and how to reduce risk around your home.
- Groundhog burrow entrances: how many there are and how to find themGroundhog burrows often have multiple hidden entrances. Learn how many holes to expect, where escape exits are usually located, and how to find them before sealing.
Sources / assumptions
- General wildlife control guidance: repellents are inconsistent outdoors; durable solutions focus on removal/exclusion and structural prevention.
- Assumes typical residential yard conditions and that legal/ethical control methods are followed.