Things not to throw on the compost heap & what to do with them instead

Things Not to Throw On The Compost Heap: 5 Things

5 Things not to throw on the compost heap & what to do with them instead

Top 5 Things Not to Throw On The Compost Heap

Are you aware of things not to throw on the compost?

As a gardener, I use compost to make my plants grow healthier. I initially used food scraps as composting material. However, I soon found out good compost is a mix of materials and not only food leftovers! Plants need a healthy mix of organic matter to grow well. After experimenting with compost I was able to create a compost recipe that made my plants grow well and healthy! If you want to know what I didn’t place in my compost, read on!

This is a two-part blog, that identifies things not to throw on the compost or that are not suitable for your urban compost pile (worm farm, tumbler, hot compost heap). The first part explains why these are things not to throw on the compost and the second part gives you some handy tips and hints for what you can do to with this stuff to minimise your waste without composting it.

Related: Complex Composting? Not So!

I will preface this blog by noting that all organic matter is compostable, which means all of the items listed here can be composted.

What is the point of the blog then, you ask?

This blog identifies things that require additional effort or special procedures in order to be safely composted, which are either not convenient or not practical in the urban context. So while possible, its best to avoid composting the things on this list if you are a city dweller or are working with a small composting space. *

Things Not to Throw On the Compost:

Meat & Dairy

The problem with meat and dairy is that it doesn’t take long for it to smell pretty bad and as a result, it doesn’t take long for it to attract pests. On the safety front, decomposing meat and dairy products may also contain nasty bacteria, so they are included in things not to throw on the compost.

Vermicomposting guru, Mary Appelhof, claims that small amounts of meat, bones and dairy work just fine in a worm farm. If you’re feeling ambitious, go ahead! But take it slowly and monitor what your farm can and can’t handle as you go.



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Citrus is a little controversial when it comes to composting. Many claim that citrus is bad for the compost heap because it is takes a long time to break down and goes moldy in the meantime. Perhaps, but this is easily remedied by cutting citrus waste up in to smaller pieces to assist the decomposition process. I say experiment if you are operating a tumbler or a hot composter. So this is also included in the things not to throw on the compost.

There are some reports that suggest that the chemical d-limonene is toxic to worms. In any case, citrus is not a favoured flavor of the composting worm. That said, I do feed my worms the odd bit of rind with no problems – I just monitor the level of citrus that goes into my farm and try not to go overboard.

The wonderful thing about citrus is that there are so many fabulous uses for it in the home that you are unlikely to run out of options for reusing your citrus scraps. Part two of this blog will reveal all. 

Onion & Ginger

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The issue with the humble onion, ginger and their family members (eg leek, garlic, shallot, chives), is that they tend to be strong on the olfactory senses, particular when the decomposition process begins, and this attracts unwanteds. They also have a tendency to resprout, which is not so bad, although not the intended objective of a compost pile (this can of course be easily remedied by cutting your onions up into small bits). This is why they are also included in the things not to throw on the compost.

Like citrus, onions do not make the list of composting worms preferred foods, although just like citrus, I’m happy to add small amounts to my worm farm and I haven’t found that it produces any odour.

There are no problems with composting onion peel.

Pet Poo

Cat, dog, ferret, whatever your pet of choice, avoid putting their poo in the compost. Pet poo can carry toxic bacteria that can be harmful to humans (think toxoplasmosis in cats and roundworm in dogs. Not cool). Of all the items on this list, pet poo should be the one to avoid composting in your urban composter at all costs.

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Related: “It’s as simple as saying Hello.” Discover our step-by-step planner for building your garden from scratch!

* Bokashi composting units will compost everything on this list. If you can’t dispose of the kitchen scraps on this list in other ways, perhaps consider a bokashi composting system. You should note that prior to using the ‘product’ derived from bokashi composting, you need to bury the waste for a time period. This may be a limitation if you do not have a large amount of ground space to do so.


Awesome photography from @mlwashenberger

About the Author


Hannah is a passionate lover of plants and has a firm belief that even the darkest corners of the concrete jungle can be greenified. Her penchant for composting and bad plant puns led to the creation of the The Worm Monger, a website that allows her to thoroughly indulge all these passions.