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Why Is My Compost Not Getting Hot – 3 Main Reasons!

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Why is my compost not getting hot? This question is not uncommon in people who have just started composting in their gardens.

Compost is a great way to add organic nutrients to the soil, help it retain moisture, and keep the plant diseases at bay, all while utilizing the waste from your kitchens effectively. Composting is easy, and you can do it right in your backyard.

An important point to remember for composting is that it needs to heat up to be used in its full capacity, but keeping the compost out in the bright sun won’t help it heat up. The compost goes through a natural decomposed process by the bacteria to attain high temperatures. So, you need to leave it outside for a few days in proper conditions to heat up. 

However, often you will notice that the compost is not getting hot even though it has been a few days which could leave you wondering – why is my compost not getting hot?

If this issue has been bugging you, we have got the answers in this guide. Keep reading.

Why Is My Compost Not Getting Hot 1
Compost not heating up? – via Reddit

Why Is My Compost Not Getting Hot?

There could be several reasons why your compost is not reaching the desired temperature. Most of the time, proper conditions are not provided to the compost. For example, it could be too wet or too dry.

An optimal temperature for the compost is between 122 to 160-degree Fahrenheit. The compost will not work properly if there is no heat or less heat. So, this issue needs to be investigated, and you need to find out the causes behind the temperature not reaching the ideal range.

Let’s explore some of the main causes that answer your question – why is my compost not getting hot?

1. There Is Too Much Moisture

Heat is produced due to the chemical reaction in the compost pile. When aerobic bacteria, those that need oxygen to decompose, attack the compost pile in the presence of air or oxygen, heat is produced as the bacteria digest the pile’s contents.

When your compost pile is too wet, it does not allow the optimal level of air to enter, and so the aerobic bacteria cannot act on the pile due to a lack of oxygen.

Consequently, anaerobic bacteria start to take up space as these bacteria decompose without using oxygen. When the anaerobic bacteria digest the contents of the compost pile, a foul-smelling gas called Methane, is produced. If your compost pile smells foul and not earthy, it is probably because your compost pile is too wet.

You can also check the compost by hand. Squeeze it, and if water leaks out, your compost pile is too wet. Also, check for a brown liquid coming out of the pile to confirm that there is too much moisture in a pile.

There are some easy ways to dry up the compost pile. You can spread the compost in a thin layer on a large surface outside the sun. Let the material dry up, and then you can gather it up in a pile. You may also add more greens and browns like leaves and grass.

If rain is expected in your area, cover up the compost with a plastic wrap or a bin to keep it dry. In the case of a rainy season, you might want to find a place for the compost to keep it dry. You might also add materials like sawdust, straw, and shredded paper to balance out the moisture level of the pile. However, make sure not to add an excess of any of this material.

2. The Size of the Compost Pile Is Not Right

The size of the compost pile significantly well how fast and how well the pile will heat up. Being too big or too small in size can cause an issue for the compost, and it might not heat up.

If your compost pile is too big, the bacteria may not be able to get enough oxygen and other ingredients needed for it to decompose the pile and produce heat. So, if you have added too many materials, scrape off some of them from the top.

If the compost pile is too small, there will not be enough material to trap the heat produced by bacteria until the pile reaches the desired temperature. All the heat will escape from the compost pile into the air.

Usually, the pile is big when starting out, and it will get smaller in size as the bacterium decompose and digests it. The ideal size for the compost pile is set out at a minimum of 3 by 3 by 3 feet, and not more than 5 feet cubed.

Why Is My Compost Not Getting Hot 2
Compost won’t heat up – via Reddit

3. The Pile Does Not Have Enough Moisture

Just like your compost pile should not be too wet, it shouldn’t be too dry, especially if you are composting in dry and hot weather. The dry conditions of the compost will not let bacteria thrive, so your compost won’t heat up.

Having the right amount of moisture in your compost pile will help the bacteria to build colonies and digest the material. 

If your compost is too dry, you can add water but be careful not to soak it. Add water through a hose or a bucket, but make sure there is no water leaking from under the pile. The pile should be wet to touch, not leaking.

Besides that, you could also add high-water content materials to your compost piles, such as fruits and vegetables. You should also use fewer dry materials like sawdust and leaves. Also, fresh grass clippings can help retain the moisture as well.  


I hope this answers your question – why is my compost not getting hot? If you are just starting out with composting, know that you need to provide enough oxygen, moisture, and space for the bacteria to work on the compost and produce heat.

Don’t worry if your first try does not go well. Keep trying with the tips mentioned above and put your home and kitchen scraps to good use.

Share your tips on how to get the best out of a compost pile.