If you want to fill chipmunk holes in your yard, it’s best to use fine gravel, sand, cement, or a combination of these materials. Chipmunks have a difficult time digging through sand and gravel because it shifts to fill any space they’ve cleared. They cannot dig through cement. Chipmunk burrows can be 20–30 feet (6–9 meters) long, with several entrances. It’s a good idea to search the area after finding one entrance in case there are other holes. Just make sure not to pour liquid, chemicals, or mothballs into chipmunk burrows. These methods are dangerous and ineffective.
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How Do You Identify Chipmunk Holes?
Chipmunk holes are typically 1–2 inches (2.5–5 cm) in diameter. They can be found in almost any part of the yard, either near foundations, near trees, or even in relatively open areas. If possible, use a flashlight to get a good look at the interior of the burrow. A gentle downward slope indicates that it is indeed a chipmunk hole. If you’ve seen chipmunks in your yard or have seen them enter the burrow, you can skip the guesswork. What you’ve got is a chipmunk burrow.
- A hole 2 inches (5 cm) in diameter.
- Visible chipmunk activity near the hole.
- No gathered or piled dirt around the hole entrance.
- The visible portion of the burrow slants downward at an angle.
- Holes covered or surrounded by dirt indicate the presence of other animals, not chipmunks.
A chipmunk hole is also identifiable by the fact that there is no surrounding mound of dirt. Chipmunks carry dirt away in their cheeks and deposit it elsewhere. If the burrow in your yard is surrounded by dirt or the entrance to the tunnel has a soft dirt “plug” then it is not a chipmunk burrow. Moles leave mounds of dirt with an open hole in the center. Pocket gophers dig holes surrounded by dirt. In many cases, gophers plug the hole with dirt to prevent snakes and other predators from entering. Chipmunk holes are notable because they are left open and not surrounded by loose dirt.
How Large are Chipmunk Burrows?
A chipmunk burrow can extend up to 20–30 feet (6–9 meters) underground. They can also have multiple entrances and exits. So, if you’ve found one chipmunk hole in your yard, search the area for more. It’s no good filling one entrance to the chipmunk burrow if the rodents have a back door somewhere.
Are Chipmunk Holes Harmful?
Chipmunks, unlike larger burrowing animals, do not damage foundations or trees with their burrowing. However, chipmunks do eat fruits, nuts, and seeds. If you don’t want them digging up your flower beds to eat plant bulbs, or you’re trying to overseed your lawn, you’ll want your yard clear of chipmunks. However, if you don’t mind having a few animals rooting through your flower beds, a small colony of chipmunks won’t do major damage to your home or property.
4 Methods to Fill Chipmunk Holes Permanently
Properly filling a chipmunk hole will drive the unwanted critters out of your yard. It can be done simply and cheaply. Just use these methods to get rid of your chipmunk infestation.
Fill with Gravel
You can seal a chipmunk hole by pouring small gravel into the hole. The best type of gravel for the job is a very small rock, no larger than pea gravel. This is because small gravel will shift and fill the space as the chipmunks try to remove it. Chipmunks like to burrow in firm dirt, where they can dig a hole cleanly. Shifting gravel will discourage them.
- Use this small gravel, no larger than ¼-inch (6 mm).
- Locate all the entrances to the chipmunk burrow in your yard.
- Use a funnel or similar tool to pour the gravel directly into the opening of the chipmunk hole.
- Push the gravel deeper into the hole with a screwdriver or tool handle, then continue filling.
- Fill the first 4–6 inches (10–15 cm) of each tunnel opening with gravel.
It’s essential to get the gravel as deep into the chipmunk burrow as possible when filling the hole. A large funnel or a folded piece of cardboard can help direct gravel into the hole. Then, you can use a screwdriver or other tool to push the gravel deeper into the burrow and continue filling. If you fill the first 4–6 inches (10–15 cm) of the tunnel, the chipmunks will not be able to reopen it.
Try Filling Chipmunk Holes with Sand
Similar to gravel, coarse sand will discourage chipmunks from digging and reopening burrows. As the chipmunk digs, the sand will slide and fill the space, halting their progress. When chipmunks encounter this unstable sand, they will give up and search elsewhere for a home.
- Fill chipmunk holes with this coarse sand to prevent chipmunks from reopening burrow entrances.
- Sand will shift and fill empty space as chipmunks try to dig through it, preventing them from excavating their burrow.
- Use a funnel to pour sand as deeply into the burrow as possible.
- Fill the hole until the sand is level with the soil surface.
As with the gravel method, it’s best to use a funnel to pour the sand as deeply into the chipmunk hole as possible. The deeper the sand goes, the more likely it is that the chipmunks will fail to dig through it.
Cap Chipmunk Holes with Cement
If you’ve got some stubborn chipmunks that re-open their burrows after you’ve filled them with sand or gravel, it’s time to use a little cement. No chipmunk can dig through cement, so you can use this method to chipmunk-proof any burrow:
- Pack this pre-mixed cement down into the chipmunk hole.
- Use a stick or tool handle to push the cement as far down into the burrow as possible.
- Continue adding and packing cement.
- Leave the top 2 inches (5 cm) of the burrow empty of cement.
- Fill the top 2 inches of the burrow with dirt.
By creating a concrete plug in the chipmunk burrow, you ensure that the chipmunks cannot reopen this entrance. Then, by packing 2 inches (5 cm) of dirt on top of the concrete you ensure that grass or other plants can grow over the concrete once the chipmunks give up and move on.
Avoid Liquids and Chemicals
Do not pour liquids or chemicals into chipmunk holes in your yard. Bleach is ineffective at driving off chipmunks and will kill helpful soil microbes. Pouring mothballs or gasoline anywhere outside is illegal in the United States and most other countries. Using these methods outdoors can poison the soil, killing plants and grass. The chemicals in these compounds can also poison the local water supply.
- It is ineffective to pour liquid chemicals, gas, or moth balls into chipmunk holes.
- Pouring gasoline or mothballs into a chipmunk hole is illegal and harmful to soil.
- Pouring water into a chipmunk hole will not have any effect.
Most liquids are ineffective at driving chipmunks away. Water poured into a chipmunk hole will be quickly absorbed by the soil. Plus, chipmunk burrows are so long and extensive that you’re unlikely to flood the entire system of tunnels. Rather than trying liquid repellents, stick to filling the holes with material that chipmunks struggle to dig through.
Can You Cover Chipmunk Holes in Your Yard?
The best ways to fill chipmunk holes that appear in your yard are:
- Pour gravel as deeply into the chipmunk hole as possible.
- Fill chipmunk holes with coarse sand.
- Push cement down into the chipmunk hole, then cover the cement with dirt.
- Avoid pouring liquid chemicals or mothballs into chipmunk burrows.
These methods close up chipmunk burrows immediately. If you have stubborn chipmunks that keep trying to dig new burrows, your next step is to use humane traps to capture and relocate pest chipmunks.