Sustainable waste disposal is crucial for our environment and our future. I’ve seen firsthand the negative impact of landfilling and incineration on our planet.

These methods contribute to greenhouse gas emissions and can harm local ecosystems.

Conversely, composting helps reduce waste, lowers methane emissions, and produces valuable compost that enriches the soil and supports healthier plant growth. However, are bones compostable?

Yes, bones are compostable. With proper composting techniques, bones can break down over time, making them a viable addition to compost piles.

The decomposition process for bones may vary depending on factors like bone size and composition.

Larger livestock bones may take several months to break down fully, while smaller carcasses like poultry can decompose in as little as 60 days. Now, let me share my personal experience with composting and bones.

I’ve often wondered if bones are compostable; I’m sure many others have.

In my composting journey, I’ve learned that while most organic materials can be composted, bones are a gray area.

Small bones from fish or poultry can break down in a well-managed compost pile, but larger bones, like those from beef or pork, are much more challenging.

My experience has taught me that you need the conditions to compost bones successfully. All of these conditions will be discussed in this blog post. Read on!

Are Bones Biodegradable?

Yes, bones are biodegradable. Bones are made of collagen (protein), hydroxyapatite (the mineral that stores calcium), tendons, and ligaments. Bones may also contain water, organic content, and bone marrow.

Are Bones Compostable?

Yes, bones are compostable. They are 100% natural and come from a living thing. Eventually, they’ll break down, releasing their nutrients back into the ground. However, it may take several years for bones to degrade.

When you compost animal carcasses, most of the bones break down, but some big ones might stick around.

Don’t worry; with proper composting, those bones will eventually break down. For bigger animal bones, it could take a few months, but for smaller critters like poultry, it might only be 60 days.

If you still see big bones in your compost, you can put them in another compost pile until they fully break down.

The span is in between 50-80 years. Bones can be assumed to be the outer layer of connective tissues. There are said to be around 206 bones in the human body.

As per the classification of bones, there are four types of bones in the body: long bone, flat bone, short bone, and irregular bone. Bones may co-act with muscles and joints in performing the required functions such as support, mobility, and movement.

Factors Influencing Bone Composting

1. Bone Size and Composition

• Size Matters

The size of bones plays a significant role in their compostability. Larger bones, such as livestock ones, decompose more slowly than smaller bones, like poultry ones.

This is because larger bones have a denser structure and require more time to break down.

• Bone Composition

Bones primarily comprise minerals, collagen, and organic matter. The mineral content, mainly calcium and phosphorus, makes bones durable and resistant to decomposition.

Conversely, Collagen is an organic protein that can decompose but does so slower than many other organic materials typically added to compost piles.

2. Temperature and Microbial Activity

• Microbial Role

Temperature and microbial activity are critical for bone decomposition. Composting relies on the action of microorganisms, such as bacteria and fungi, to break down organic matter, including bones.

•   Optimal Temperature

Microbial activity is most efficient within a specific temperature range, often referred to as the “thermophilic” phase, which is typically between 130°F to 160°F (54°C to 71°C).

Achieving and maintaining this temperature range is essential for effective bone decomposition.

• Slow Decomposition in Cold Temperatures

In colder climates or during the winter months, compost piles may not reach the optimal temperature, leading to slower decomposition rates, including for bones.

3. pH Levels in the Compost Pile

• pH Balance

The compost pile’s pH level can influence the bones’ decomposition. Most compost microorganisms thrive in a neutral to slightly acidic pH range of 6.5 to 7.5. Maintaining this pH range is crucial for efficient composting.

• Effect on Bone Decomposition

If the compost pile becomes too acidic or too alkaline, it can hinder the decomposition of bones. Bones are particularly sensitive to extreme pH levels, which can slow down or even prevent their breakdown.

4. Use of Accelerators or Enhancers

• Accelerators

Some composters opt to use accelerators or enhancers to facilitate bone decomposition.

These can include compost activators or microbial inoculants that introduce a higher concentration of beneficial microorganisms into the compost pile.

• Carbon-Rich Material

Mixing bones with carbon-rich materials, such as dried leaves, sawdust, or cardboard, can also serve as an accelerator.

Carbon-rich materials help balance the compost pile by providing a carbon source that complements the nitrogen-rich bones.

•  Balancing Act

Achieving the right balance between carbon-rich and nitrogen-rich materials in the compost pile, especially when bones are involved, can be critical to ensuring efficient decomposition.

How to Compost Bones for Gardening

Step 1: Hot Composting

Hot composting is the preferred method for breaking down animal bones efficiently. Here’s why:

• Heat and Microbes: Hot composting generates high temperatures inside the compost pile, creating an environment where beneficial bacteria thrive. These bacteria accelerate the decomposition of bone material and help reduce odor.

• Avoid Cold Composting: Adding bones to a traditional cold composting pile is not recommended, as they can attract animals due to their smell. To avoid this issue, opt for hot composting.

• Alternative: If you don’t have a hot compost pile, you can bury bone scraps in your garden. Dig a hole at least two feet deep and place the bones inside. Cover the hole with a flat piece of wire mesh to deter animals and secure it with a large rock.

Step 2: Break The Bones

Breaking bones into smaller pieces is crucial for speeding up decomposition:

• Enhanced Surface Area: Cutting or breaking bones into smaller pieces exposes more surface area to the microbes in the compost pile, facilitating quicker breakdown.

• Tools: Invest in bone-cutting shears for poultry bones or use a hacksaw for larger bones. Alternatively, a hammer can be used to break bones into smaller pieces.        

Step 3: Compost Pile Placement

Proper placement of bones within the compost pile is essential:

•  Avoid Surface Placement: Never place bones on top of your compost pile, as this can attract pests.

• Center of the Pile: The best location for bones is deep inside the center of the compost pile, where temperatures typically reach 140-160 degrees Fahrenheit (60-71 degrees Celsius). This heat encourages microbial activity and bone decomposition.

•  Minimize Disturbance: Try not to disturb the bone-containing section of the pile for several weeks to allow the microbes to work effectively.

•  Pest Prevention: Burying bones in the pile’s center also discourages flies from swarming and animals from digging them out. The more material you have between the bones and the outside of the pile, the better.

• Pest Consideration: If pests are a problem in your area, consider using a compost bin with secure doors to prevent access.

Step 4: Practice Patience

Composting bones requires patience, as they take a considerable amount of time to fully disintegrate:

• Variable Decomposition Rates: Different types of bones decompose at varying rates. For example, chicken and fish bones may dissolve in just a few months, while thick bones from beef, pork, or game like deer can take nine months or more.

• Experimentation: Experiment with different bone preparation methods and compost pile ingredients to find the most effective technique for optimal results.

• Re-composting: You can bury or re-compost any bone remnants after completing a compost batch.

What Is The Best Way to Compost Bones

Another effective method for composting bones, especially if you have concerns about pests or odor, is to use a specialized composting system like Bokashi.

How Bokashi Works: Bokashi is an anaerobic fermentation process that involves layering bone scraps with a special bran inoculated with beneficial microorganisms.

This method allows you to compost bones and other food waste in an airtight container without using traditional composting conditions. Bokashi is particularly useful for urban or small-space composting.

Different Kinds of Bones That Can Be Composted

1. Wild Game Bones

The wild game has huge frames and tough meat. Composting takes years, but you can shorten the duration by boiling and breaking the bones into particles to speed up the process.

2. Fish Bones

Fish bones will take a short time to process because they are thin and small. There is no need to pre-boil or cook.

3. Chicken Bones

The small, soft bones will break down naturally without even cooking.

4. Pork Bones

Bones from pigs are also compostable but may take much longer to break down since they are thicker than chicken bones.

5. Beef Bones

Beef bones and other wild game like deer or elk are large and thick, reducing the chances that the entire bone will dissolve inside your compost bin or compost tumbler soon.

Unless you have plenty of space and time to deal with large bones, it may be best to forgo adding them to your composter.

Benefits of Composting Bones

Composting bones offers several valuable benefits, both in terms of waste reduction and soil enrichment. Let’s discuss these benefits in detail:

1. It Reduces Waste in Landfills

One of the primary benefits of composting bones is that it diverts organic waste away from landfills. In many waste management systems, bones are typically disposed of in landfills, which occupy valuable landfill space.

Also, landfills are already burdened with various types of waste, including non-biodegradable materials.

By composting bones, we reduce the amount of space bones would otherwise occupy in landfills, extending the lifespan of these disposal sites.

Lastly, landfills can have negative environmental consequences, such as soil and water contamination, as well as the release of methane, a potent greenhouse gas.

Composting bones helps mitigate these adverse effects by keeping them out of landfills.

2. It Contributes to Nutrient-Rich Soil

Composted bones, when fully broken down, contribute valuable nutrients to the soil. Bones are rich in minerals, primarily calcium and phosphorus, essential for plant growth and health.

In addition, the organic matter resulting from the composting process enhances soil structure. It increases soil aeration, water retention, and nutrient availability, promoting healthier plant growth.

Finally,  Nutrient-rich compost, including decomposed bones, can reduce the reliance on chemical fertilizers. This shift toward organic soil enrichment is environmentally friendly and can lead to more sustainable agriculture and gardening practices.

3. It Reduces Greenhouse Gas Emissions

Composting bones as part of organic waste management helps reduce methane gas production.

When organic materials, such as bones, decompose anaerobically in landfills, they release methane, a potent greenhouse gas that contributes to global warming.

Composting, on the other hand, encourages the conversion of organic matter into stable organic carbon, which is less likely to escape as methane.

This sequesters carbon in the form of compost, helping to offset greenhouse gas emissions.

By reducing the emission of methane and promoting carbon sequestration, composting bones, and other organic materials play a vital role in mitigating climate change and minimizing the environmental impact of waste disposal.

Potential Challenges You May Encounter While Composting Bones

1. Slow Decomposition of Bones

Bones, especially larger and denser ones, decompose slower than other organic materials commonly found in compost piles. This slow decomposition can lead to the accumulation of bones in the compost pile over an extended period.

Consideration: To overcome this challenge, breaking bones into smaller pieces is essential before adding them to the compost pile.

Smaller fragments have a larger surface area, making it easier for microorganisms to break them down. Additionally, patience is required, as bones may take several months or even years to fully decompose.

2. Attracting Pests

Due to their odor and nutrient content, Bones can attract pests such as rodents, raccoons, or stray dogs. Pest infestations can disrupt the composting process and create unsanitary conditions. Little side note, you can also use dog hair for compost.

Consideration: To prevent pest attraction, bury bones deep within the compost pile’s center, surrounded by other compostable materials.

This minimizes the scent’s exposure and deters pests from digging into the pile. Consider using a compost bin with secure doors or lids to protect against unwanted visitors.

3. Odor Issues

The decomposition of bones can sometimes produce unpleasant odors, which can be a concern, particularly in urban or densely populated areas.

Consideration: Proper aeration and turning of the compost pile can help mitigate odor issues by promoting air circulation and reducing anaerobic conditions contributing to foul smells.

Balancing the compost pile with carbon-rich materials (browns) like leaves or sawdust can also help neutralize odors. Using a compost bin with a lid can contain odors effectively.

4. Ethical and Cultural Considerations

Composting bones may raise ethical and cultural considerations, as bones can hold cultural significance or be viewed as inappropriate for composting in certain communities.

Consideration: It’s essential to respect cultural and ethical beliefs when considering bone composting. In cases where composting bones is deemed inappropriate, alternative disposal methods, such as burial or cremation, may be more suitable.

Open and respectful communication with individuals or communities with specific concerns is essential to responsible waste management.

Conclusion

Bones are compostable but come with unique challenges, including slow decomposition rates, potential pest attraction, and odor concerns.

Despite these challenges, composting bones is a viable and eco-friendly option that can reduce waste and enrich the soil.

The successful composting of bones relies heavily on employing proper techniques. Breaking bones into smaller pieces, burying them deep within the compost pile, and maintaining balanced composting conditions are essential.