Composting : Frequently Asked Questions

Can I compost kitty litter?

Cat litter is not compostable in most home facilities. To kill the diseases found in cat feces, a compost pile must reach a temperature of at least 165 degrees Fahrenheit. The bacteria and germs found in cat feces and kitty litter can potentially be harmful to both humans and other animals. Some commercial facilities may reach this temperature for a long enough period, but don’t necessarily accept cat litter and feces. Some kitty litter contains perfumes or other additives that aren’t biodegradable, and therefore can’t be composted even if unused. Please check with your local facility and comply with their policies regarding kitty litter.

Suggested ways to make kitty litter more sustainable or “Earth-Friendly”:

• Use lightweight litter (to reduce negative impacts of shipping).
• Avoid litter made out of sodium bentonite, which is often mined in an unsustainable manner.
• Choose kitty litter made from sustainable material, such as recycled newspaper, wheat, or coconut. 

Can I compost meat/bones/dairy?

Including meat, bones, and dairy in a home compost pile can have several complications. These include: attracting pests, causing unpleasant odors, and potentialy introducing pathogens to your pile. Therefore, at home composters must monitor temperature, C:N ratio and accessibility to the pile very carefully if they desire to compost these items at home.

Can I compost plant material that has been contaminated with disease/pesticide/herbicide?

“Don’t put grass, hay or plants treated with pesticides or herbicides in your compost bin or food scrap container. Both can harm the beneficial insects, bacteria, and fungi that do the work to turn dead vegetative material into compost. Talk with your drop-off facility about what materials they will accept if you have pesticide or herbicide treated materials. You may also consider managing these materials at home in a separate pile. ” [ANR]

Can I compost biodegradable and compostable coffee cups, silverware, or other compostable plastics and paper?

Typically, no. Most composters will not compost any “compostable disposables” at this time. These items look like trash and therefore confuse staff as to which container is for compost and which is for trash.  When composting compostable disposables, trash also migrates into the compost pile and totes and is more difficult to detect and separate. In addition the Northeast Organic Farming Association (NOFA) has ruled that compostable disposable plastics are not natural and therefore cannot be turned into organic approved compost which is another reason that composters do not typically compost compostable disposables.
The Caveat: Some compostable disposables are manufactured using 100% paper, cellulose, or bagasse (a byproduct of sugarcane production) and do not contain compostable plastics. These products often can be composted without jeopardizing organic approval of the finished compost. Always contact the manufacturer of a product to obtain the MSDS (Material Safety and Data Sheet) in order to learn what it is made of AND contact your composter when in question about the compostability of a certain “compostable disposable.”

I’ve seen some packaging or grocery bags that say “biodegradable” or “degradable” on them, can I put them into my compost pile/tote?

In general the only products that are truly compostable are those approved by the Biodegradable Products Institute or BPI. Beware of front organizations claiming to certify other types of “degradable” products. Some chemical companies now make “bio-degradable” or “degradable” products, which are made of petroleum plastic that, over time, will break down into small pieces of plastic unnoticeable to the human eye. This deceptive marketing is dangerous because adding plastic to soil has been found to harm plant growth and affect human health. In general, truly compostable products will bare the Biodegradable Products Institute logo:

Is separating food scraps for composting, including post consumer food scraps, legal?

Yes. According to the Vermont Department of Health’s, Health Regulations for Food Service Establishments, Section 5-213 Garbage and Refuse Disposal, Item 34 Garbage and Refuse Disposal Areas – Construction and Cleanliness, Point G – Community or Individual Facilities, Disposal and Composting, states the following:

2. Food waste may be disposed of by composting with the following requirements:

A. Compost sites cannot be in close proximity to the outer openings of a food service establishment.

B. A compost site must be properly operated and kept free of insects, rodents, and vermin.

3. Compost sites cannot create a health hazard or nuisance to any food establishment or neighboring property owner.

Why shouldn’t you compost store bought flowers?

Store-bought flowers are often grown in other countries where the flowers are treated with pesticides and fungicides that you don’t want making their way into compost piles. Many of these chemicals have the potential to harm microbial life in the compost pile, thus hindering the composting process. In addition many of these chemicals can persist beyond the composting process, resulting in a compost that may harm plants and humans rather than help them. Most flowers are not meant for human consumption and those that are not from your back yard should not be put into the compost totes or into compost piles.

How long does it take for food scraps to turn into usable compost?

Generally it takes between 6 to 12 months to create finished compost depending on the process, volume, and management.

I’ve heard food scraps in the landfill produce methane gas. Do food scraps in a compost piles release methane?

Methane is produced under anaerobic conditions (without air or oxygen). Food scraps and other organic matter contained in plastic bags in sealed landfills do not have access to air, which in turn promotes the development of anaerobic bacteria (bacteria that thrive in environments lacking in oxygen), which release methane as they digest the food scraps. Properly managed compost piles are turned or aerated maintaining proper oxygen levels. This oxygen promotes aerobic (with air) microbial populations, which do not release methane gas when they break down and eat food scraps and other organic matter.  Studies have shown that properly managed compost piles release negligible amounts of methane.