Is Mould In Compost Safe? Why Is It Happening?

Last Updated on April 8, 2024 by Real Men Sow

Mould in compost has a cotton-like texture. Mould’s color (typically green or black, white, pink, or white) is determined by the material it is fed. It can also be affected by the climate and location.

What Are The Different Types Of Mould in Compost?

White Mould

It is common problem that can be found in compost on wood particles. A hot compost with white mould is a good indicator that the compost is properly decomposing.

Green Mould

The most popular color in compost because it grows best in compost with a lot of food waste.

Pink Mould

It’s often caused by cleaning chemicals in your compost. These cleaning products can kill organisms that aid in the process of decomposition. This type of mould must be eliminated by not allowing soap-based water to enter your compost pile.

Can Mould in my Compost be Harmful to Me?

The mould in your compost pile won’t cause any harm if you handle it during the turning process. You should not ingest the mould. However, there are exceptions. Some people may be sensitive to mould spores.

How To Avoid Inhaling Mould From Composts?

To prevent inhaling these spores, you should always use a mask to turn your compost. Your compost pile may contain harmful bacteria and mould if it has any meat or dairy products. These products can attract pests and animals that could get sick from your compost.

Basic Requirements of Compost

For great composting, compost must meet certain basic requirements. These include adequate moisture, oxygen, and organic material. Organisms can’t live without these natural resources.

Sufficient moisture

The most important factor in composting is moisture. The success of compost depends on how much moisture is present, this is because decomposers require sufficient moisture to survive. Insufficient moisture can cause bacteria to slow down. However, if the moisture level is too high, it will cause the water to force out the air. Your compost will then have an unpleasant odor.

How To Determine If The Compost Is Moist Enough?

There are many ways to determine the moisture content in a compost pile. The squeeze test is one of the most straightforward methods to measure the moisture content of a compost pile. If your compost is too dry it will not form a ball if you squeeze it in your hands. When you squeeze the compost, it will drip water out if it is too moist. If the compost moisture is right, it will form tiny droplets and glisten when you squeeze it with your hands.


Proper aeration plays a crucial role in composting. Regularly turning the pile can improve air movement. Adding corn stalks, straw, and other coarse materials high in carbon can also encourage air pockets. Your compost will become clumpy if it is the same consistency as thick layers of grass, or full leaves. To allow organisms to breathe and thrive, it is important to add different amounts of material.

Organic materials

Organic materials are the core of compost, even though they aren’t the only part. A healthy, fertile compost requires the use of appropriate organic materials. This is a 50/50 mix of greens and browns. The microorganisms grow best when there is green, and browns provide air for the compost pile.

Simple Ways to Fix Struggling Compost With Mould

  • You will have less air exchange if your container has small openings. You should ensure that the compost is placed in an open area. To ensure that compost has more airflow, it should be turned over with a pitchfork or shovel.
  • It is usually a sign that your compost pile is too wet. This can be fixed by adding more browns such as dried leaves to your compost pile. They will absorb water.
  • Mixing organic materials is easier if you can break down and shred them into smaller pieces. This will make your compost more efficient and faster. This gives you more material per piece and makes it easier for tiny organisms to get to it.

Things That Do Not Belong in a Compost Pile

Not all types of waste belong in a compost heap. Some waste can cause problems for compost. Here is a list of items to avoid and their reasons.

Coal Ashes

It can be tempting to cover mould in compost with ashes. However, this is a bad idea as coal ashes can contain harmful substances for plants like iron and sulfur.

Meat and Dairy Products

In addition to creating an unpleasant odor, the main attraction for insects, animals, and pests is waste from dairy and meat products. This can disrupt the process of decomposition. Therefore, these types of products should not be included in compost piles.

Chemical Pesticides

Anything that has been treated with chemicals should not be used to disturb compost. Some people may spray their lawns with chemicals, but this can kill beneficial organisms for composting.

Pet Waste

Pet waste could contain pathogens or viruses that can damage compost.

Breakable Items

Materials such as metal and glass will find it difficult to break down your compost. They will only cause more disruption to the process.

Benefits of Composted Soil

Compost is the best way to create rich soil. Composting improves a soil’s value. It attracts beneficial bacteria and fungi to plants’ growth process. This also increases soil’s capacity to hold nutrients and water, which promotes plant growth. It is safe for the environment as it doesn’t disturb your garden and does not cause any harm to innocent insects. It is also a great way to fight plant diseases and pests. The soil can be maintained at an acid or alkaline level by adding compost. Composting is an economical and easy way to improve your garden.

The best soil food is compost. Correctly made compost will smell like soil, and the decomposed material won’t be identifiable. The best thing about compost is that it contains organic matter that has been decomposed. This rich soil will give plants great growth and yields.

Frequently Asked Questions

Can I put mouldy food in the compost? 

Yes, since mould is a sign of decomposition. This is exactly what a compost pile is designed to accomplish. The decomposition process has already started by adding mouldy foods to the compost pile.

What if the compost is too wet? 

It will not be able to make the beautiful soil that it can produce if it is too moist. If the compost seems too wet, you can add dry ingredients such as paper shreds, cardboard, and dry leaves to it.

How to avoid too much bad-odor from the compost? 

To get more air in the compost, turn it upside down. A smelly compost is also an indication that it is too wet. For more tips, see the previous question.

Can you put bread in a compost pile? 

Avoid putting bread-type products in a compost pile as they can attract pests and animals.

Real Men Sow
Real Men Sow

Hello, I’m Pete and I’m currently based in the west of Scotland, in a small place called Rosneath, where I’m exploring my garden adventures. I personally started gardening around 6 years ago and initially, I started out by growing my favorite fruits and berries, such as strawberries, Raspberries & Gooseberries. Since then I’ve added a lot of vegetables and working closely with my neighbor, it’s been a lot of fun.