Can I Put Moldy Items In Compost?

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In Brief: Can I Put Moldy Items In Compost?

Moldy food is quite common, and we often come across moldy fruits, veggies, and bread, among other items. Throwing them in the trash can seem like waste, especially if you have a compost heap. But can you put mold items in your compost pile? Yes, you can! But there are certain rules and specifications to keep in mind. Here is when and how you can put moldy items in compost.

Moldy food is not something rare. It happens quite often that we take out moldy scraps from the fridge.

Most of us simply want them out of sight, and they are often placed right into the garbage can. However, there might be a better way of using moldy items – for compost.

Let’s find out how you can use moldy food to enrich your compost and how safe this is.

Can I Put Moldy Items In Compost?

The excellent news is that moldy items can be put in compost. In fact, this might be the best thing you can do with them.

One main reason for this is because mold is the first stage when food scraps decompose.

Mold spores are all around us, and they will find their way into your compost, too. Thus, there is no need to add them.

If mold spores come in contact with a surface that does not provide enough nutrients, nothing happens.

They can only “come alive” on foods with sufficient organic compounds.

Most foods start to grow mold when sugars, such as starch, or another basic element come in contact with moisture. Soon after that, mold becomes visible, and we all know the color and texture of these moldy patches.

At this moment, the best you can do is put the food in the compost heap.

If you always thought that moldy food was useless, this is the time to change your mind. Moldy items in compost can only bring benefits to the composting process, so it’s the best thing you can do.

On the other hand, not all moldy items can be placed in the compost. In general, fruits and vegetable mold as a result of microbiological processes, which makes them safe for composting piles.

Produce from both the garden and the fridge is suitable to be placed in the heap.

One main problem is that not all mold or rotting is caused by the same processes or microorganisms. For instance, lettuce that becomes slimy and brown is not suitable for your compost.

It would definitely get broken down, but the risks increase significantly. Leafy greens are populated by E. Coli, Listeria, and Salmonella, all of which cause serious illness.

The leafy green does not spoil because of this bacterium. Actually, leafy greens that already contain these bacteria get spoiled, and the bacteria survive the mold or rot.

If the leafy greens are from your own garden, then they might be safe, unless you use manure or a tainted water supply.

As a result, you can compost most of your moldy foods. Make sure you avoid moldy meats or dairy products, as these should not make their way into the heap.

There are also several types of mold that should concern you if they are present. White mold can be noticed in the compost heap, mostly on woody materials.

This is not troublesome, as it is an indicator that your compost is successfully decomposing.

Green mold, however, is often encountered in heaps with lots of food scraps and waste. It also shows that your compost heap has way too much moisture, so make sure you balance out the dry ingredients.

Green mold can become quite an issue, as it spreads quickly by digesting nitrogen-carbon compounds.

If you notice large amounts of mold of any type in your compost pile, it’s best to wear gloves and a mask when you work around it. Although there is a low risk, Aspergillosis and Histoplasmosis are two infections that can be caused by inhaling fungi.

Once the decomposition process is complete, the mold will also die off, which makes your compost safe to use in the garden.

If you would like to find out what exactly you can and can’t put in your compost pile, check out this video:


Some also wonder if they can compost moldy/rotten plants in compost. The answer is yes and no, depending on when and how the plants decay.

This can be a normal process, for instance, when the weather cools down as the growing season is coming to an end.

This means that you can add them to compost after you inspect them carefully for any insect population. If the plants die instead of thriving in full season, these should be destroyed and not added to the compost pile, as they might carry diseases.


All in all, you can reuse moldy items by putting them into the compost heap. However, it is important to make sure that these products are not contaminated.

For instance, if you compost leafy greens, it’s best to do so only if you grew the leafy greens yourself, as many store-bought leafy greens contain different bacteria.