What Can Be Composted – What to Include, What to Exclude

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In Brief: What Can Be Composted – what to include, what to exclude

Some materials are better forming compost than others. But you may be wondering what is on the include list and what is on the exclude list. You certainly wouldn’t want to harm the nutrients in your compost pile by mistakenly adding the wrong thing. Here is an in-depth look into what you should include when making compost and what to avoid.

Are you always unsure of what to throw in your compost bin? If you are looking for answers on what to add to your compost bin for healthy and nutrient-rich soil, then you have come to the right place.

It is always important to understand what adds value to your compost and what does not.

What Can Be Safely Composted

To get healthy and high yields from your compost, you must be mindful of what you add to it. Always consider a variety of ingredients.

Your compost will turn out richer when you do this, packed with micronutrients, perfect for the soil’s microorganisms.

The following are things you can add to your compost:

  • Manure from herbivorous animals
  • Leaves
  • Dust from vacuuming
  • Grass clippings
  • Sawdust, burnt matches, and wood chips
  • Shredded newspaper (black and white only)
  • Vegetable food scraps and leftovers (avocado skins, potato peels, and lettuce)
  • Cardboard
  • Fireplace ashes
  • Hay
  • Wool and cotton rags

Guiding Principles to What Can Be Easily Composted

When deciding what to compost, always make sure you have numerous ingredients, as they will increase your compost’s quality.

All organic materials can be added to your compost. You should, however, consider the brown to green ratio. This refers to the ratio of carbon-rich materials to nitrogen-rich materials.

When you notice your moisture is excessively wet, we recommend adding browns, and if it is dry, add greens. The right balanced mix will give you a healthy compost.

The size of the materials you add to your compost will also determine what will be decomposed much faster and easier. You have to make sure the materials you add to your compost have the most surface area, which will help speed up the decomposition rate.

Just cut up the bigger chunks of waste, for example, bread or potato peelings, into small pieces to give the bacteria greater surface area.

The decomposition rate of the contents of your compost is very important. Some may take longer to decompose, while others decompose much faster.

For example, vegetable waste and grass cuttings break down much quicker than cardboards. Even though each of them has important purposes in your compost, you should consider the decomposition rate.

Materials that Require Special Time and Preparation

With some materials, you could just add them to your compost and leave them to decompose. However, some materials require special attention and preparation.

These include:

  • Pinecones
  • Hair
  • Used clothes and other natural fabrics such as cotton, silk, and linen
  • Egg cartons
  • Tissue paper
Source: Earth 911

The Guiding Principle on What Should not be Composted

There are some materials which, when added to your compost, will result in a negative result.

Inorganic materials such as aluminum, metals, and plastics should be avoided at all costs. This is because the materials they are made of can make the compost toxic.

When adding to your compost, keep off all invasive weeds; these include Canada thistle and creeping Charlie. This is because they have a higher chance of coming back to grow and spread where your compost is.

Even though they can be composted, avoid adding any type of weed to your compost. The weeds tend to spread fast.

If you have problems with raccoons, rodents, or pests, do not add foods with animal products. Foods such as dairy, eggs, fats, and oils tend to attract animals to your compost.

Even though these products are suitable for your compost, they could cause a pest problem. This can be curbed by using bin locks that you could close.

However, if you have an open bin, make sure you keep away from these products.

Fish, meat, poultry scraps, and eggs can also cause odor problems. This can make living unbearable, especially if you have the compost close to the house.

Meat and bones can also cause your compost to overheat and attract animals too.

Materials to Avoid Composting

There are some materials which you should never add to your compost. The following are some of them:

  • Droppings from cats and dogs
  • Bones, meat, dairy products, and fish skins
  • Chemically treated yard waste
  • Black walnut twigs and leaves
  • Insect-ridden or diseased plants

Why Some Materials Need More Time Composting

When it comes to decomposition, various materials decompose at different rates. The breakdown depends on the nature of the substance.

When you cut down, chop, or break down materials into little pieces, they will decompose much faster. Adding the correct green to brown ratio also helps speed up decomposition.

Materials such as wood will take a longer time to decompose as compared to potato peelings. It all depends on the nature of the material you are adding to your compost.

Aeration also plays a key role in the time it takes to decompose. You should always turn your pile frequently and move the materials around for better aeration.

Source: Field Museum

What Special Prep is Required for Certain Cases of Composting?

Different materials require different prepping before you dump them in your compost. For wood chips and twigs, we recommend you chop them up into little pieces for faster decomposition.

Increasing the surface area of the helps to increase the decomposition speed.

A large amount of surface area will be exposed to microbes and air. Since they are also rich in carbon, they will require nitrogen to break them down. Mix them up in small layers and moderate amounts.

Kitchen waste, such as fruit and vegetable trimmings, are perfect for the compost and rich in nitrogen. Leftover foods should also be cut up for faster decomposition before being added to the compost.

They, however, can cause odor and a lot of moisture. This attracts pests to your compost. We prefer you to use an enclosed compost bin for this type of kitchen refuse.

Grass is also another perfect material to add to your compost. However, it also compacts, and the result is an oxygen-free material.

Due to grass having over 50% water, it turns anaerobic. We recommend that you mix it with other components in your compost, such as sawdust and soil, to curb this.

It works best if you just spread grass on the top of the compost.


What can I cover my compost pile with?

You could use dry grass. If it is during the winter, consider something that insulates your compost. You could use a carpet or straw bales that allow water and air to pass through.

What foods can be composted?

Fruits, vegetables, grain, bread coffee filters can be composted. Generally, if it can be grown or eaten, it can be composted. However, remember that eggshells, meat, and dairy products that can attract unwanted pests and rodents to your compost.

How often should I turn compost?

You should turn your compost frequently, preferably at least every two to three weeks. Waiting this long allows the center to heat up and helps increase bacterial activity.


Deciding what to compost and what not to compost is very tricky at times. However, as we have seen, most organic materials are perfect for the compost.

Some require special attention and prepping more than others. You should also consider the type of compost you have. Enclosed compost bins are perfect for most types of food trimmings and leftovers.

Open composts also have the benefit of proper aeration. So the next time you are wondering whether or you can put something in the compost or not, consider the nature of the material, the decomposition rate, and whether it will overheat or attract unwanted visitors.

We hope this article has shed some light on what to compost and what not to compost.