29 Things You Can’t Compost | What Not to Compost

Composting is a great way to make your organic fertilizer; it allows you to decompose the waste material of the garden and food scraps of your home, which otherwise would have been thrown into the trash. Meanwhile, you can compost almost anything organic and be once-living, but there are some things you can’t compost, or you should avoid composting them to a large extent to avoid the hassle. So what are these? Find out what not to compost in this list.

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What Not To Compost?

1. Inorganic and Non-Biodegradable Materials

You should never dump any inorganic and non-biodegradable materials such as plastic, glass, coated cardboard, cellophane, aluminum foil, and metal into a compost pile because they will never break down. Also, avoid any pressure-treated lumber must, too, as it contains chemicals.

2. Tea and Coffee Bags

You should only add tea and coffee to the compost pile when they are bagless. It is crucial to remember that some bags can contain synthetic fibers that will never break down in a compost bin. 

So, do not add any coffee or tea bags to the pile unless you are 100% sure that they are made of natural materials such as hemp or cotton. 

3. Citrus Peels, Onions, and Garlic Scraps

It is best to keep onions, garlic, and citrus peels from your compost bin as they may end up scaring some beneficial insects and bacteria. They can even kill worms and other beneficial organisms. 

4. Rice

Rice is also unsuitable for your compost heap. Raw rice can attract pests, while cooked rice can be the perfect ground for bacteria to grow. Both versions of rice can be potentially bad for your compost’s nutrients, so it is best to avoid them. 

5. Coated or Glossy Printed Papers

Don’t compost magazines, catalogs, old business cards, and wrapping paper or papers with a glossy appearance, as chemicals and toxic substances can later damage your plants. However, you can compost newspapers, textbook pages, or papers with less or no ink.

6. Leather Goods

Your old wallet, purses, belts, gloves, etc., are organic, but they may not be ideal for your compost bin. They will take years to decompose, and also most leather accessories are often treated with life-extending chemicals. So, in that case, it can also cause harm to your compost nutrients. 

7. Cigarette Butts

Some cigarettes are loaded with harmful chemicals, and the butts are made of plastic. If you plan on dumping all the cigarette butts into your compost bin, assuming they are organic, think twice. Plain untreated tobacco is compostable, but not any cigarettes. 

8. Stickers on Fruits and Veggies

Ensure the tiny or big plastic stickers on fruits and vegetables should be removed before tossing them into the compost pile. These small plastic stickers are a huge source of contamination in compost all across the globe. These stickers cannot even break down in industrial composts. 

Also, get rid of those annoying stickers by directly buying organic produce from the farmers or by growing them in your garden by yourself. 

9. Torn or Shredded Clothing

Do not dump even the tiniest shred of fiber into your compost bin, as it can contain harmful materials and chemicals. Also, some dyes are used in making clothes colorful. So, unless you are sure that the clothes are 100% organic, do not use them in the compost bin. 

10. Diseased and Infested Plants

It takes a compost pile to maintain a temperature of 141-145°F or 60-62°C for 7-10 days to kill disease pathogens and insects. However, not all home compost bins can maintain or even reach such high temperatures. So, it is ideal not to add any plants affected by diseases and bugs. 

11. Bakery Products

Products such as cakes and pastries attract pests, insects, and animals. However, you can compost slices of bread or pasta but do remember when you put any food scrap in the compost pile, bury it deep so that it will not invite unwanted beings.

12. Feces and Manure of Carnivorous Animals

Meanwhile, the poop and manure of vegetarian animals like chickens, goats, cows, horses, and rabbits are beneficial for your plants. On the contrary, you should not throw the litter of your dogs and cats or other carnivorous animals or human feces into the compost heap because this can carry pathogens and parasites that transmit infectious diseases and are harmful to humans. 

Also, roundworms in the feces of dogs are very common, and litter from cats can carry organisms that can be responsible for a disease called toxoplasmosis. This disease can cause serious harm to pregnant women and unborn children. 

13. Eggs

Another item that can be harmful to your compost bin is eggs. If you have old or rotten eggs, do not dump them into the container as they attract pests. 

14. Bread

Although the ingredients in bread may add nutrients to your finished compost pile, the issue is with the smell. The smell of bread attracts insects and pests like a magnet, and tossing in the leftover toasts can be another great way to call those hungry, wild critters and raccoons to your garden. Also, it will create a foul smell in your garden that your neighbors may not appreciate. 

However, maybe a tiny crust now and then on a giant compost pile may not harm your garden, but definitely, a loaf of bread surely will. 

15. Cooking Oil

There are reasons why you should not add cooking oil to your compost pile. First of all, it can slow down the composting process. Also, it has a smell that can catch the attention of animals and insects. It is found that cooking oil can alter the moisture level of the compost too.

16. Meat Products

They decompose very slowly and stink a lot. Annoying insects like flies, maggots, etc., may buzz over them. Moreover, they also attract rats, raccoons, cats, and stray dogs. You should avoid any leftover meat and animal fats in the compost pile.

17. Fish Scraps

The fishy stench of leftover or old seafood is a foul smell, and these repulsive odors attract skunks, rats, raccoons, other wild critters, and flies like a magnet. So, you should avoid dumping fish scraps in the compost bin unless you want to call for a picnic for the local fauna. Even if you have a covered compost bin, it may not be suitable to dump that in as it can still draw unnecessary attention. 

18. Dead Animals

You may think that dumping a dead mouse or your dead pet goldfish into the compost bin is a good idea but do not do it. Do not try composting dead animals for the same reason you should avoid fish, eggs, or meat scraps in a pile. 

19. Dairy Products 

Avoid composting dairy products like milk, butter, sour cream, yogurt, and cheese, if you don’t want to invite pests and rodents. You should also avoid any processed food with lots of dairy for the same reason. 

20. Fat Based Condiments and Foods

Peanut butter and oily salad dressing cannot break down just as cooking oil, grease, animal fat, and butter. They will also attract pests and shift the moisture balance to the pile. So, it is best to avoid any fat-based foods in the heap of compost. 

21. Personal Hygiene Products

Tampons, sanitary towels, diapers, tissue papers, stained materials with human blood, or other personal hygiene products can pose a health risk and be avoided.

Although some people may argue that you can add dryer lint to your compost pile and others will vote against it, it is best to avoid it. Your lint may contain plastic, and unless you are sure the lint is from cotton clothing only, do not add them. 

24. Sawdust

You can compost sawdust as it soaks excess moisture in wet compost heaps, but sawdust from treated wood needs to be avoided. Also, you should include it in the layers of compost, and you just have to consider that it is essential to put it in small quantities.

25. Weeds

The word weed is enough to tell you why you should not compost it. Instead of breaking down, the weeds may set down roots, and plants will regrow again in a heap. Also, adding their seeds will germinate again whenever you amalgamate compost into the soil.

26. Tomatoes

There is no problem with composting tomatoes. However, you should avoid composting tomato fruits unless you want baby tomato plants sprouting everywhere in your garden when you’ll use that compost.

27. Plants treated with Pesticides and Herbicides

Never put plants or grass clippings on the lawn treated with fungicides, pesticides, or herbicides, and do not dump them into your compost pile. The leftover chemical residue in these plants meant to control plant diseases and kill insects can also harm the beneficial composting organisms. The residues from herbicides may cause damage to your plants in the garden if added to the compost. Also, the same thing applies to treated, stained, varnished, or painted wood and should be avoided. 

28. Black Walnut Tree Debris

Most yard and garden wastes can make for an excellent addition to the compost bin, but there are some exceptions, like the Black Walnut tree debris. You should never add the leaves, twigs, and roots to your compost pile as it contains a natural chemical called juglone that can even kill other plants. 

Although research shows that juglone may break down enough not to be toxic anymore, however, even then, it is best to leave out adding any parts of the Black Walnut tree to the compost. 

29. Charcoal Ash

Although adding wood ash to compost from your wood-burning outdoor fire pit or fireplace in limited quantities can be a good idea. It may not be ideal for adding charcoal and coal ash. These materials are loaded with sulfur, making your compost too acidic for most plants. Also, charcoal briquettes are frequently infused with chemicals that can harm your plants. 

Surprising Things You Can Compost

Now that you are aware of what you should avoid in composting, here are a few waste products that you can add to the compost pile. Also, only add these items if you are keeping the things mentioned above in mind:

• Unused paper napkins and paper towels
• Unpopped or burned popcorn
• Cardboard and paper plates (small pieces, uncoated)
• Aquarium plants
• Old herbs and spices
• Hair and fur
• Wooden chopsticks and toothpicks
• Homebrewing wastes (spent hops and malt)