Unveiling the Surprising Items You Should Never Compost

What Should Not Be Composted: A Guide to Proper Composting

Composting is a fantastic way to reduce waste and create nutrient-rich soil for your garden. By turning organic matter into compost, you can contribute to a healthier environment and improve the health of your plants. However, not all materials are suitable for composting. In this blog post, we will discuss what should not be composted to ensure you have successful and sustainable composting.

The Importance of Knowing What Not to Compost

Before getting into the specifics of what should not be composted, it’s crucial to understand why certain items are unsuitable for the process. Adding improper materials can disrupt the balance of your compost pile or bin by introducing harmful toxins, pests, or pathogens that may contaminate both your soil and future plant growth.

Inorganic Materials

Avoid Plastics in Your Compost Pile

Plastic materials take an incredibly long time to break down naturally. Therefore, avoid adding any plastics or synthetic materials such as plastic bags, bottles, wrappers, or straws into your compost pile. These items do not decompose quickly nor provide any nutritional value.

Say No To Metals in Your Heap of Compost

Metal objects like nails, screws, tin cans should also never find their way into your composter as they cannot decompose organically and may pose a risk when handling the final product.

Dairy Products and Animal Waste

Avoid Dairy Products in Your Compost Bin

Dairy products like milk, cheese scraps or yogurt should never be included in a regular backyard composter since they can attract pests such as rats or raccoons and create unpleasant odors if not thoroughly mixed with other organic materials.

Animal Waste Requires Special Handling

While animal manure can be a valuable source of nutrients, it is recommended to avoid adding it directly to your compost pile. This is especially true for pet waste or any feces containing parasites or pathogens that could potentially contaminate the soil. If you are planning on using animal waste in your composting, do thorough research on proper handling techniques or consider seeking professional advice.

Treated Wood and Sawdust

Avoid Pressure-Treated Wood in Your Compost Pile

Pressure-treated wood contains chemicals like arsenic and chromium that help preserve its durability but are toxic to plants and harmful when present in compost. Avoid adding treated wood scraps into your compost heap.

Cautiously Use Sawdust as Composting Material

Sawdust from untreated wood is acceptable but should be used sparingly as it decomposes slowly due to its fine texture, which may disrupt airflow within the pile. Too much sawdust can lead to compacted layers affecting decomposition processes.

Oily Foods and Grease

Avoid Adding Oily Foods into Your Compost Bin

Foods soaked in oil or greasy substances should be kept out of your composter. These oily residues tend to trap moisture, resulting in anaerobic conditions leading to bad odors rather than healthy decomposition.

Invasive Weeds and Diseased Plants

Do Not Add Invasive Weeds into Your Composter

< p > Certain weeds such as bindweed
or dandelions can quickly spread
and take over gardens. Avoid composting these invasive weeds to prevent spreading their seeds and roots in your compost or garden.

Dispose of Diseased Plants Properly

Diseased plants, including those infected with fungi, bacteria, or viruses, should not be added to the compost pile. The warmth and humidity generated by the process may help these pathogens survive and potentially harm other plants when using the finished compost in your garden.


To ensure successful and sustainable composting, it is essential to know what materials should not be included in your composter. By following these guidelines and avoiding items such as plastics, metals, dairy products, animal waste (unless properly handled), treated wood scraps, oily foods/grease,
invasive weeds,
and diseased plants,
you can create a healthy environment for beneficial organisms while maximizing the nutrient-rich benefits of your homemade compost.

Remember that maintaining a proper balance between green (nitrogen-rich) and brown (carbon-rich) materials will significantly contribute to an effective decomposition process.
Happy Composting!