Composting 101: What Not to Use in Compost

Don't put meat, dairy, or oils in your compost pile, as they can attract pests and create odors.

These types of materials can also attract rodents and create a mess.

Pet waste, on the other hand, can contain pathogens that can harm humans and animals alike.

Weed seeds from invasive plants can sprout in your compost and spread to your garden, causing more problems than they solve.

Meat and fish scraps are a no-go for your compost pile. They'll attract pests like skunks, raccoons, and rats, and even your neighborhood pets.

Avoid putting meat, bones, and related animal byproducts in your compost. They can result in unhealthy colonies of insects and bacteria that are bad for you and your crops.

Dairy products like milk, sour cream, and cheese should also be left out. They're magnets for pests and can make your compost pile smell terrible.

Fats and oils will linger in your compost pile and may even ferment and spoil. This can attract pests and create an unpleasant smell.

Synthetic soaps and used feminine hygiene products are also not compostable. Even tiny slivers of standard bar soap can contain synthetic chemicals that don't belong in your pile. Most pads and tampons contain plastics or synthetic fibers and should never go in your compost.

Human feces and diapers are a definite no-no for your compost pile. They pose a significant health risk and can contain diseases and parasites.

Kitchen scraps can be a challenge to compost, but it's essential to know what to avoid. Meat and fish scraps are a definite no-no, as they attract pests like skunks, raccoons, rats, flies, and more.

You should also steer clear of dairy products like milk, sour cream, yogurt, cheese, and butter, as they're also magnets for pests. Oils and fats are another no-go, as they can ferment and spoil before being broken down.

Here's a quick rundown of what not to compost from your kitchen:

Onion and garlic scraps are also best left out, as they can affect the compost's microbial balance. And don't even think about adding cooked rice or pasta – they can attract pests and create unpleasant odors.

Don't melt standard bar soap in your compost bin, as it can contain synthetic chemicals that don't belong there.

You can't compost used feminine hygiene products, like pads and tampons, in your regular home compost bin, even if they're made of organic cotton.

Human feces and diapers are a no-go for your regular home compost bin, as they can contain diseases and parasites.

Don't even think about composting disposable, biodegradable nappies, as they're not yet home-compostable.

On a similar theme: Earth Worm Compost Bin

Avoiding treated and diseased materials is crucial when creating a compost pile. Adding plants or wood treated with pesticides or preservatives can harm beneficial composting organisms.

You should never add plants to your compost that have been treated with insecticides, fungicides, or herbicides. The residue of these chemicals can unintentionally kill the beneficial composting organisms.

Trimmings from plants that have been previously treated with pesticides should also be avoided. This includes plants that have been sprayed with herbicides, which may affect plants once the compost is added.

A hot compost pile can kill insects and disease pathogens, but most home compost bins and piles don't reach high enough temperatures to do so. It takes a temperature of 141 to 145°F for at least several days to kill fungi and bacteria.

If this caught your attention, see: What Type of Soil for Succulent Plants

Debris from black walnut trees should be avoided in compost piles, as they contain the toxin juglone, which can harm many plants.

Leaves or twigs from these trees can contaminate your compost and cause problems when it's time to plant.

The good news is that composting can be a safe and effective way to recycle yard waste, but it's essential to know what not to include.

Dog and cat poop never should go in your compost pile because they can turn the end product into hazardous waste. Both cats and dogs can carry bacteria and parasites that cause human disease.

Roundworms are the most common issue with dog poop. Cat feces and cat litter are an even greater concern because they can carry the organism that causes toxoplasmosis, a disease of particular concern to pregnant women.

Dog and cat feces and litter must be composted separately in special, high-temperature pet waste composters. This is because carnivorous and omnivorous animals' intestines can host a wide range of resilient parasites and pathogens.

Cat poop is especially dangerous, so it's essential to handle it with care. Manure from other purely plant-munching pets or livestock, however, is very beneficial.

Dead animals should not be composted, as they will stink, attract pests, and grow potentially unwanted pathogens.

Black walnut debris is a no-go for your compost pile. Most untreated garden and yard waste is welcome, but black walnut leaves, twigs, and roots contain a natural substance called juglone that stunts the growth of many plants.

Juglone is particularly toxic to edible crops like tomatoes, peppers, and potatoes. It's also a problem for ornamentals like azalea, viburnum, and hydrangea. Certain plants are more sensitive to this toxin than others.

Leaves or twigs from black walnut trees contain juglone, which can harm peppers, potatoes, and tomatoes. This toxin can be a major issue for gardeners who value these plants.

With enough time and heat, juglone does break down, but it's better to err on the side of caution and leave out black walnut debris altogether.

Additional reading: Can Leaves Be Composted

You'll be surprised at what you can't compost in your yard. Dryer lint is a big no-no, containing fabrics and potentially contaminating your pile.

Synthetic fabrics of any kind can't be composted, and that includes even small amounts like the 1% polyester in a 99% cotton t-shirt.

Leather goods, like worn-out belts and gloves, are also off-limits due to oil finishes and unknown chemical ingredients.

Dairy products are a no-go for composting, as they can attract pests and create unpleasant odors.

Meat and bones can also be problematic, as they break down slowly and can attract rodents and other unwanted critters.

Pet waste, especially from carnivorous pets, can be too high in nitrogen and create an imbalance in the compost pile.

Coal ash is a big no-no for composting, especially if you're aiming to create a fertilizer for your plants. This is because coal ash contains substances that can harm plants, potentially killing your vegetable garden.

Coal and charcoal ash are particularly problematic, as they can make your finished compost too acidic for most plants. This is due to the high sulfur content in these materials.

Charcoal briquettes are often infused with chemicals that can harm plants, making them a poor choice for composting.

Broaden your view: What Worms Are Good for Composting

Paper with lots of color printing or Sharpie-drawn inks can contaminate your compost pile, so it's best to leave them out.

Glossy paper is toxic to your compost pile, which means some magazines and product catalogs are off-limits.

Modern printer inks and markers are usually free from heavy metals, but they can still contain synthetic dyes and other chemicals you don't want in your compost.

Any paper with a glossy plastic finish, including most wrapping paper, should be avoided in your compost pile.

See what others are reading: Can Paper Bags Be Composted