How Long Does It Take for Biodegradable Plastic to Decompose?

Biodegradable plastic typically takes between 90 days and several years to decompose, depending on the environment. In commercial composting facilities, it can break down in about 90 to 180 days, while in landfills it may take 5 to 20 years, and even longer in environments with low oxygen, moisture, or microbial activity.

Biodegradable plastic has emerged as one of the most promising developments in sustainable packaging, offering the potential to drastically reduce waste, pollution, and the long-term environmental impact of human consumption. Yet, one of the most common questions consumers and businesses ask is: How long does it take for biodegradable plastic to decompose? The answer is not quite as simple as giving a single number, because the decomposition rate depends on many different factors, including the type of biodegradable plastic, environmental conditions, presence of microbes, heat, exposure to sunlight, and how the plastic is disposed of.

In this comprehensive blog, we will explore what biodegradable plastic is, how it breaks down, different types of biodegradable plastics, how long they take to decompose in various environments, and why proper disposal is just as important as using eco-friendly materials. We will also compare biodegradable plastics to traditional plastics so you can see the true environmental impact.

Understanding Biodegradable Plastic

Before discussing decomposition timelines, it is essential to understand what counts as biodegradable plastic. Traditional plastics are made from petroleum-based polymers that are extremely difficult for nature to break down. In fact, conventional plastic items can take anywhere from 400 to more than 1,000 years to fully decompose, if they decompose at all. This is why landfills and oceans are filled with plastic bags, bottles, wrappers, containers, and packaging that have remained intact for decades.

Biodegradable plastics, on the other hand, are created with organic or plant-based materials that microorganisms such as bacteria, fungi, and algae can naturally break down. These plastics are often made from:

• Corn starch
• Cane sugar
• Potato starch
• Algae
• Cassava
• Cellulose
• Plant-based polymers

Instead of breaking down into microplastics that pollute food chains, biodegradable plastics are designed to decompose into water, carbon dioxide, and biomass, leaving behind minimal long-term environmental impact.

The Difference between Biodegradable, Compostable, and Oxo-Biodegradable

There is some confusion in the market because several terms sound similar but mean different things. Understanding the difference helps clarify how long each type of plastic takes to decompose.

Biodegradable Plastic

This type can break down through natural microbial activity, but does not require specific industrial conditions. However, the decomposition speed depends heavily on temperature, moisture, and oxygen.

Compostable Plastic

Compostable plastics are a specific category of biodegradable plastics that decompose into nontoxic natural materials under controlled composting conditions. Many certified compostable plastics break down in 90 to 180 days if placed in a commercial composting facility.

Oxo-Biodegradable Plastic

These plastics contain additives that cause them to fragment into smaller pieces when heated or exposed to UV light. While they appear to “break down,” they often degrade into micro plastics, which can still enter the environment and harm ecosystems.

Understanding these categories makes it clear why not all biodegradable plastics decompose at the same rate.

Factors Affecting the Decomposition Rate of Biodegradable Plastic

The time it takes for biodegradable plastic to break down depends on many factors, including:

• Type of bio plastic
• Amount of heat present
• Sunlight exposure
• Moisture levels
• Oxygen availability
• Number of active microbes
• Whether the environment is natural or industrial
• Product thickness and chemical composition

For example:

A thin compostable bag in an industrial facility may decompose in 90 days, while the same bag buried in a dry landfill without oxygen may remain intact for years.

This is why understanding disposal conditions is just as important as choosing biodegradable products.

How Long Does It Take for Biodegradable Plastic to Decompose?

Because different conditions affect breakdown rates, decomposition times vary widely across environments. Let’s compare the most common places biodegradable plastics end up.

In a Commercial Composting Facility

This is the ideal environment for biodegradable or compostable plastics. Professional composting centers maintain high temperatures (around 140°F), moisture, oxygen flow, and thriving microbial colonies.

Under these controlled conditions:

Most compostable plastics break down in 90 to 180 days.

This includes:

• Bio plastic food containers
• Plant-based packaging
• Compostable shopping bags
• PLA cutlery and utensils

A commercial composting facility is the fastest and most efficient way to decompose biodegradable plastic, but unfortunately, only a small percentage of plastic waste reaches these centers.

In a Home Composting Bin

Home composting is more accessible but less controlled. Unlike industrial compost centers, most backyard systems:

• Do not reach high temperatures
• Have inconsistent oxygen levels
• May contain fewer microorganisms

Because of this, many biodegradable plastics take longer to break down in a home compost environment.

Average time to decompose at home:

6 months to 3 years

Even certified compostable plastics may not decompose efficiently unless the home compost pile is well-maintained.

In Landfills

Most trash collected by municipal waste systems ends up in landfills. Unfortunately, landfills are one of the worst places for biodegradable plastic to decompose.

Why?

Because landfills are:

• Low in oxygen
• Dry
• Compacted
• Limited in microbial activity

This means even biodegradable plastics may remain intact for decades. Typical decomposition time in a landfill:

5 to 20 years or longer

This is still significantly shorter than the hundreds of years required for traditional plastics, but it is far slower than composting environments.

In Soil or Natural Outdoor Environments

If biodegradable plastic is left in soil with moderate oxygen and moisture, microbes can begin breaking it down.

In natural soil environments, decomposition may take:

1 to 4 years

Again, the specific timeline depends on temperature, rainfall, microbial life, and the thickness of the plastic.

In the Ocean

Marine environments pose unique challenges. Decomposition in the ocean is slower due to:

• Low oxygen
• Cold temperatures
• Limited microbial activity

Biodegradable plastic in the sea may take:

2 to 10 years or more

However, this is still dramatically better than traditional plastic, which can stay in the sea for centuries.

Comparing Biodegradable Plastics to Traditional Plastics

To better understand the environmental impact, here is a comparison:

Traditional plastic bottle decomposition:

450 to 1,000 years

Biodegradable plastic bottle decomposition:

90 days to 5 years, depending on the disposal environment

Traditional grocery bags:

10 to 100 years

Compostable grocery bags:

90 to 180 days in compost

This comparison shows just how significant biodegradable materials can be in reducing long-term pollution. However, this benefit is realized only when the plastic is disposed of properly.

Why Disposal Matters More Than Most People Realize

Many consumers assume that simply purchasing biodegradable products is enough to reduce waste, but improper disposal can dramatically slow decomposition. For example:

• A compostable fork thrown into regular trash may sit in a landfill for ten years.
• A biodegradable shopping bag littered on a roadside might take several seasons to disappear.

The best-case scenario is always:

Commercial composting

• Home composting (if suitable for the material)
• Organic recycling programs

This is why education and access to composting infrastructure are just as important as manufacturing eco-friendly alternatives.

Types of Biodegradable Plastics and Their Breakdown Time

Different bio plastics degrade at various rates. Here are common types and estimated decomposition times:

PLA (Polylactic Acid)

Made from corn starch or sugarcane

Decomposes in:

• 90 to 120 days in industrial compost
• 6 months to 2 years at home
• Several years in the soil
• Much longer in the landfill

PHA (Polyhydroxyalkanoate)

Made by microbial fermentation

Decomposes in:

• 120 to 180 days in compost
• 1 to 3 years in natural environments
• PHA is considered one of the most environmentally friendly bio plastics.

Starch-Based Plastics

Made from potato, corn, or cassava

Break down faster:

• 3 to 6 months in compost
• 1 to 2 years in soil

Cellulose-Based Plastics

Derived from wood pulp or cotton

Breakdown in:

2 to 12 months, depending on the environment

Are Biodegradable Plastics the Perfect Solution?

Biodegradable plastics are a huge step forward, but they are not a single magic solution for the world’s waste problem. Key challenges include:

• Limited commercial composting facilities
• Consumer confusion
• Higher manufacturing costs
• Mislabeling in the marketplace
• Slow decomposition in landfills

However, when disposed of correctly, biodegradable plastics drastically reduce:

• Landfill volume
• Ocean pollution
• Wildlife ingestion
• Micro plastic accumulation
• Long-term ecosystem damage

The Role of Businesses in Sustainable Waste Reduction

While consumers play a role, businesses have the greatest ability to change the future of packaging waste by choosing biodegradable materials, educating customers, and investing in responsible disposal systems. Fox Tail Packaging contributing to this shift by offering eco-friendly packaging options that are far safer for the environment.

Final Thoughts

So, how long does it take for biodegradable plastic to decompose? The real answer is:

It depends.

In a commercial composting facility:

90 to 180 days

In-home compost:

6 months to 3 years

In soil:

1 to 4 years

In the ocean:

2 to 10 years

In a landfill:

5 to 20 years or longer

While these numbers vary, biodegradable plastics still decompose far faster and more safely than traditional petroleum-based plastics that can pollute the planet for centuries.

The key takeaway is that biodegradable plastics must be disposed of properly to deliver their environmental benefits. When combined with consumer awareness, business responsibility, and advanced waste-processing infrastructure, biodegradable plastics represent a major step toward a cleaner, healthier, and more sustainable future for the planet.

Frequently Asked Questions

How long does it take for biodegradable plastic to decompose?

Biodegradable plastic can decompose in 90 days to several years, depending on environmental conditions.

Does biodegradable plastic decompose in landfills?

Yes, but much slower. In landfills, biodegradable plastics decompose in 5 to 20 years due to limited oxygen and microbial activity.

What helps biodegradable plastic break down faster?

Heat, moisture, oxygen, and active microorganisms help biodegradable plastics decompose more quickly, especially in composting facilities.

Is biodegradable plastic better than normal plastic?

Yes. Traditional plastic can take centuries to decompose, while biodegradable plastics break down much faster and leave fewer long-term environmental impacts.

Can biodegradable plastic decompose in the ocean?

It can, but slowly. In ocean environments, biodegradable plastics may take 2 to 10 years to break down because of low temperatures and limited oxygen.