9 Best Compostable & Biodegradable Trash Bags To Greenify Garbage Day

What Are Biodegradable Trash Bags?

Before we dive into biodegradable bags, here’s a quick refresher on what it means to be “biodegradable.”

According to Merriam-Webster, biodegradable is that which is “capable of being broken down, especially into innocuous products by the action of living things (such as microorganisms).” 

Sounds innocent enough, right? 

Until you realize that plastic being broken down into microplastics is not an eco friendly way to dispose of household waste, dog poop, or anything. 

What are biodegradable trash bags made of?

Biodegradable trash bags typically fall into two material categories: biodegradable plastic bags and those made with bioplastic. 

Biodegradable plastics are typically just petrochemical-based plastic designed so that exposure to certain things will help them break down faster. 

What’s bioplastic?

Bioplastic, on the other hand, is usually made from plant-based and renewable materials, like corn, grains, sugarcane, starches, and vegetable oils. 

One of the most common types of bioplastic is PLA (polylactic acid). 

To make PLA, the sugars found in sugarcane, corn starch, or cassava are immersed in a hot water-sulfur dioxide solution so that the different components (fiber, protein, and starch) become “available”. 

The starch is then separated out, some citric acids are mixed in and voila, we have PLA that can be used as an alternative to polyethylene, polystyrene, and polypropylene. 

Another type of bioplastic is PHA or polyhydroxyalkanoate. It’s made from genetically-engineered microorganisms that consume organic materials to produce carbon reserves. 

This microbe-made PHA has a plastic-like structure that can be harvested for trash bags as well as food packaging, medical products, and more. 

Mater-Bi is another type of plant-starch bioplastic and true cellophane (as opposed to synthetic cellophane) is made from regenerated wood cellulose. 

One benefit of all bioplastics is that they are free of toxins like bisphenol A (BPA). That, and they’re generally quicker to break down than conventional plastic trash bags.

How long does it take biodegradable trash bags to decompose?

However, their breakdown rate depends on what these bags are made of and where they end up.

You might see words like “photodegradable” or “oxo-degradable”, which means plastic bags that break down in sunlight or air, respectively (read: living organisms aren’t involved). 

But when they enter the environment (where living organisms are present), biodegradable plastic bags are just as bad as regular plastic trash bags (despite their much higher price tag)!  

Are biodegradable garbage bags compostable?

Compostable and biodegradable bags are one in the same, right? 

Some biodegradable bags are compostable, but not all. It depends on what they’re made of. 

For composting, we need to look for bags that are specifically made (and certified) for this purpose. 

Are biodegradable trash bags recyclable? 

While trash bags are recyclable, unfortunately, biodegradable plastic can’t be recycled like other types of plastic. Worse, they can contaminate otherwise perfectly sorted recyclables.

What Are Compostable Trash Bags?

Compostable trash bags are the next-level trash bags.

Before we discuss why compostable bags have the capacity to be the best biodegradable garbage bags, let’s refresh what “compostable” actually means (or take a deep dive into some lesser known composting facts, if you like).

According to Cambridge Dictionary, compostable is “something that can be used as compost when it decays.”

Like biodegradable, compostable materials can fully break down into natural elements, but they can also become something that’s beneficial for the soil (AKA humus…and not the kind you spread on crackers).

How long does it take compostable trash bags to decompose? 

For something to be legally biodegradable, it must break down in a “reasonably short” period of time—which leaves a LOT of room for interpretation and subsequent greenwashing.

Compostable products, on the other hand, must break down in 12-24 weeks. 

How do compostable trash bags work?

Compostable garbage bags have to meet certain criteria to be deemed “compostable.”

Most often, this means meeting the three basic provisions of the ASTM D6400 standard:

1. The product must experience physical disintegration, to the point that it is not “readily distinguishable” from the finished compost product. 
2. Actual biodegradation must take place, meaning that microorganisms consume the product at a rate similar to other, well-known compostable materials. 
3. The products left at the end of the composting process must not harm or diminish plant growth.  

Essentially, a compostable material must “reach or exceed 90% conversion of the carbon within the material into carbon dioxide (CO2)” during a specific time frame (usually 180 days).

This means that just 10% will return to the soil as compost and the majority will enter our atmosphere as greenhouse gas emissions.

BUT (and it’s a big but), all this is based on perfect compostability, using a high-heat industrial composting facility—not an indoor compost bin that can’t reach high temperatures.

This brings us to perhaps the most important aspect of compostability: proper disposal. 

How to dispose of compostable trash bags?

By now you might be asking: are compostable trash bags better than biodegradable trash bags?

Yes, but if and only if they are properly disposed of.

Using compostable garbage bags doesn’t give you free rein to dispose of them however you please. 

Your green compostable trash bag isn’t so “green” when you consider that, if sent to a landfill, the anaerobic (AKA oxygen-absent) conditions will lead to a release of methane—a greenhouse gas with 100-year warming potential 28x higher than carbon dioxide. 

It’s incredibly important to properly actually compost a compostable trash bag so that it can break down aerobically via naturally occurring microorganisms. 

Otherwise, it’s arguably worse than a plastic bag.

Put another way, a compostable bag needs five things: microbes, moisture, oxygen, heat, and time. 

Without these, they could end up either not decomposing, or releasing harmful greenhouse gasses into the environment—which is why a dedicated waste stream is necessary. 

Fortunately, more industrial composting facilities are popping up around the globe, along with dedicated food and yard waste bins for curbside pickup.

If you don’t live in an area with curbside composting, you can use the Find A Composter website (US only) to find out where to send your bagged food scraps. Many composting facilities are classified according to accepted feedstocks which vary by state, so be sure to look for those that accept mixed solid waste (usually Class I). 

Alternatively, the best compostable trash bags can be composted in a backyard compost bin!

Or look up local farmers and community gardens who might gladly take on your neatly-bagged compostables. 

However, because a home compost environment is very different from municipal and industrial facilities, you can only safely do this if they are certified home compostable. 

Currently, the only certifications for this are TUV Austria’s OK compost HOME certification and ABA’s Home Compostable Verification logo. There aren’t any home compost standards in the United States. 

What are acceptable compostable trash bags?

There are a few things to look for when it comes to compostable garbage bags that are actually compostable. 

Check for certifications/logos from the following:

• The Biodegradable Products Institute (BPI): Their Compostable Logo indicates that the product meets either ASTM D6400 (includes bags) and/or ASTM D6868 (for packaging).

• TUV AUSTRIA: They provide three different certifications, OK compost HOME S0014 (okay for home composting systems); SOIL S0014 (biodegradable); and OK compost INDUSTRIAL S0014 (okay for industrial composting systems).

• European Bioplastics Standard: This standard, EN 13432 is used for compostable materials that disintegrate after 12 weeks and fully biodegrade after six months. Look out for their Seedling Logo. 

• Australasian Bioplastics Association’s (ABA): The AS 5810 Home Compostable Logo is one of the few standards indicating home compostability. AS 4736 is also commonly used, meaning suitable for commercial composting facilities.

Compostable Vs Biodegradable Trash Bags

So, which is better: biodegradable or compostable trash bags?

If you’re wondering where to buy biodegradable trash bags, we’ll provide you with a better option: go for compostable instead.

Even the best biodegradable bags don’t stand up to properly-disposed-of compostable options. 

According to a recent study, degradable bags and biodegradable bags were still able to carry a load of groceries AFTER THREE YEARS IN THE SOIL.

Compostable bags, on the other hand, were still intact but couldn’t carry weight. However, within three months, they did completely break down in a marine environment.

Compostable bags on the whole may be better, but different brands vary a lot. 

If you’re wondering where to buy compostable trash bags, we recommend sticking to the ones we’ve listed.