Are Bears Attracted to Compost? The Simple Answer

Composting may seem impossible in bear country, with bears notorious for getting into any available food source – from campsites to bird feeders. However, many people wonder if food scraps and compost will bring bears to your area – and the answer isn’t as straightforward as you may have thought.

Poorly maintained compost attracts bears due to its strong odor similar to rotting eggs, which can be detected up to 1-2 miles (1.6-3.2 km) away, making them think there’s a source of food and attempt to access your pile. Well-maintained compost doesn’t attract bears.

In this article, I’ll explain why your compost might smell strong enough to attract bears and what you can do to address the issue. I will also detail some ways to bear-proof your compost. So, let’s talk about it. 

Reasons Your Compost Smells and How to Fix Them

Healthy compost doesn’t smell, so you might be doing something wrong if there’s any odor. When you compost, the feedstock absorbs the smells of decomposition and contains the odor within the pile. 

However, when something goes wrong in the internal environment of your compost pile, it starts to emit bad smells that attract bears and other pests like white worms and fruit flies. In addition to bears, your compost could also attract scavengers like feral dogs, raccoons, rats, and other creatures. 

The best way to keep these pests and scavengers and pests out of your compost is to identify why your compost smells and address the issue so your compost stops attracting pests with its smell.

So, let’s diagnose your compost pile and figure out why it stinks. 

Not Enough Air

Often, compost ends up smelling bad because you have not turned and aerated it enough.

Composting occurs when bacteria process the organic matter in the composting feedstock and decompose it. Like all living organisms, these microbes need air to survive

When the bacteria have sufficient oxygen, they thrive and multiply, which accelerates the breakdown of the compost. These aerobic bacteria break the composting feedstock down faster than anaerobic bacteria with very little odor

However, when there’s insufficient air, the aerobic bacteria die, which slows down the decomposition process. Eventually, when all the aerobic bacteria are dead, the anaerobic bacteria start to take over, which begins the process of decomposition without oxygen. 

The odor of fermentation expressed by anaerobic bacteria working on the composting feedstock attracts fruit flies and other pests and scavengers like bears. 

If your compost is emitting a foul odor, looks compact, and feels cold, it is likely because you haven’t turned and aerated it enough. The average compost pile needs a rotation every 3 to 4 days to ensure that it is fluffy and has the minimum 5% oxygen concentration required for the aerobic bacteria to use up as they work. 

To fix a lack of aeration in your compost, turn it, add more browns like dried leaves through the mix and turn it again. The browns will break up the compost particles, allowing room for air circulation. 

Finally, cover the freshly turned compost with a fresh layer of browns to absorb the odors and pop on the compost lid to help insulate the pile. Check on your heap regularly and turn it every other day if necessary until the smell dissipates and your compost heats up because of aerobic decomposition. 

Not Enough or Too Much Moisture

Compost needs water as much as it requires the feedstock of browns and greens to decompose effectively. Compost that is too dry invites colonization of ants and fungi, which might appear as white powder on your compost. 

A too dry pile also becomes acidic, which results in a more pungent ammonia smell. Maintaining a moist, slightly alkaline pH value in the compost pile helps control odors by preventing the development of malodorous organic acids. 

Dry compost also decomposes very slowly, which means that the kitchen scraps in your pile lie there, rotting slowly and attracting many scavengers like bears with their smell. However, wetter compost will decompose much more quickly. 

So, water your compost regularly to ensure that it stays moist. You can also add lime or ash to your compost pile to increase the pH value and make the compost more alkaline. 

However, too much moisture is worse than too little moisture, as the water will drown the aerobic bacteria and kill them. The dwindling numbers of aerobic bacteria will slow down the process of decomposition until anaerobic decomposition sets in and releases sulfurous odors that attract bears to your compost. 

Too dry compost can be fixed by turning and spraying the compost with water every time you turn the mix. 

You can remedy soggy compost by adding more browns to soak up the moisture. Then, turn the pile to incorporate them so they can absorb all the excess water. 

Ideally, your compost should have about 40-60% moisture, with the dampness of a wrung-out sponge when squeezed. 

Addition of the Wrong Compost Scraps

Compost scraps include kitchen waste and yard clipping like rotting fruit and vegetables, peels and cores, grass, twigs, and sticks

You should not add cooked leftovers, dairy, grease, meat, and fish to home composting units, as they take a while to decompose. They also release strong odors as they break down, which attracts scavengers like rodents, raccoons, and bears.

Adding too much fruit can also attract bears, as the smell of such a large quantity of fruit breaking down at once will attract bears to your compost. 

Remove any dairy, meat, or leftovers from your pile if they’ve started smelling, and bury them in a deep hole in the ground. Then, turn the compost to aerate it and cover it with a thick layer of browns to absorb the smell. 

A Pile That Is Too Small

While composting can be adjusted to just about any household size, composting units smaller than one cubic yard are usually counter-productive. 

Smaller composting piles have fewer microbes, which slows the process of decomposition down. The slower decomposition rate results in organic acid production that releases bad odors that attracts bears and other scavengers to your compost. 

You should ensure that your composting unit is at least 3 feet (0.9 m) in height, width, and length to ensure that your pile is large enough to compost quickly. 

Imbalanced Feedstock

The balance of your browns to greens is essential for keeping your compost odor-free. Maintaining a balanced biome in your compost will ensure that it doesn’t attract scavengers.

Excess nitrogen in your compost heat can heat the compost too quickly, burning through the materials. However, too much nitrogen could also slow the process down by adding too much moisture to the pile. Having too many greens in your pile also means that the browns can’t absorb all the odors. 

As bears are attracted to the smell of rotting food, you need to ensure that you place a layer of browns, such as dried leaves, paper, and twigs, on the top of the pile to ensure that the smell doesn’t escape. 

You should layer your compost like lasagna. It should start with a thick layer of browns, then greens, then another layer of browns, and so on. You should layer the browns in a ratio of 3:1 to ensure that the greens are fully covered. 

How Do I Keep Bears Out of My Compost Bin?

Apart from containing the odors from your bin, there are several ways that you can manage your compost in bear country to keep them out of your compost bin. 

Here’s how you can keep bears out of your compost bin:

  1. Store your collection bins inside.
  2. Place the compost away from the edge of the forest.
  3. Keep a rag soaked in ammonia.
  4. Use sturdy bins.

Store Your Collection Bins Inside

Collection bins are the bins you put your kitchen scraps and yard waste in before layering them into your compost bin. Whatever your reasons for using a collection bin, you should not store them outside, as these bins filled with food waste will attract bears. 

Instead, you can store your compost scraps in the freezer, preventing them from decomposing prematurely. 

Place the Bins Away From the Edge of the Forest

Bears don’t like crossing open areas like parking lots and, like all wild animals, they prefer to avoid human beings. Keeping your bins closer to your house or the road is an excellent way to discourage bears from rooting through your bin. 

Keep a Rag Soaked in Ammonia

A strong ammonia smell will deter bears, so you can place a rag soaked in ammonia around your bin to prevent bears from being attracted to your compost.

You’ll need to re-soak or replace the rag every few days to ensure that the smell stays strong. Because this process takes some maintenance, it’s best only to use this method in the warmer months when bears are out and about. 

Use Sturdy Bins

Using sturdy bins that bears cannot get into is an excellent way to keep bears away from your compost. Ideally, you should dig the bins into the ground, so avoid using containers on stands like the tumbler-style bins. Ensure that your container has a sturdy lid that a bear or other pest cannot open easily.

Final Thoughts

Bears are attracted to poorly maintained compost that releases pungent smells. You’ll need to keep your compost pile balanced with browns and greens and keep aeration high to prevent odors. 

The compost pile should be one cubic yard at the minimum, with the right balance of browns to greens for healthy, odorless compost. You can also take measures like storing your collection bins indoors, using sturdy containers, and keeping an ammonia-soaked rag nearby to keep bears out of your compost.

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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