Why Does Compost Get Hot?

When people start researching the perfect compost, one of the first things they’ll learn is that compost piles have to be kept at a certain temperature to turn out just right. It isn’t that difficult, but it means that if the pile gets too hot or too cold, they’ll need to do something about it.

Compost piles get hot due to the micro organism breaking down the organic matter. Heat in the compost pile is a good thing and means the composting process is working well. Periodic turning of the compost pile will help keep the temperature just right and speeds up the composting process.

Compost piles are naturally going to be warm, especially if they are turned regularly so they can be aerated. But if the compost gets too hot, the organisms on the inside of the pile won’t be able to work their magic, which means the results won’t be great. If people want to do something about this, however, it’s easier than they think.

The Right Temperature for Compost

According to many, the best temperature for a compost pile is 160 degrees Fahrenheit. Does that mean it has to be exactly that temperature 100% of the time? No, but it should be as close to that number as often as possible.

If people ever wonder, can compost get too hot, the answer is “yes,” it can, but it is very rare that this happens. At a certain point – namely, above 200 degrees Fahrenheit – the composting process will be compromised, meaning it won’t come out like the gardener wanted it to.

This is because the worms and other tiny creatures that help the composting process run smoothly can be killed if the temperature inside the compost is too hot. Excessive heat can also remove some nitrogen in the compost, and nitrogen is crucial in the composting process.

Of course, high temperatures are necessary for the composting process to move along as it should, which is one of the reasons people have to turn the compost regularly. Turning the compost on a regular basis keeps it at the right temperature and speeds up the composting process.

When a compost pile isn’t turned regularly, the temperature can actually get too low and the composting process can slow down. This is something no one wants. It can also compromise the process and cause it to come out less than perfect.

People also sometimes wonder if their compost will catch fire because it is so hot. Again, this is extremely rare, especially if they keep the compost nice and moist by watering it on a regular basis. It is mostly large commercial composting operations that have to be concerned about composts catching on fire.

How to Tell If Compost Is Too Hot

Gardeners often wonder if their compost is too hot, and even though this rarely happens, it’s still a good idea for those people to be aware that this is a possibility. Although composts need the sun and heat to turn out right, too much heat can destroy the work the gardener has put into the process.

One of the things people can do to make sure their compost doesn’t get too hot is to make sure the ratio of browns (leaves, straw, pine needles, and so on) to greens (grass clippings, food scraps, and so on) is correct. They should aim for three to four parts brown to one part green, or something very close to this.

Turning the mixture once a week and watering it one to two times per week will help a lot when it comes to keeping the compost pile at the right temperature. People who notice that the pile is too dry in between waterings can still add some additional water at that point. It can’t be too wet, but it does have to be damp.

Turning compost
Yay Turning compost

A good idea when it comes to making sure the compost is wet enough is to keep the compost materials as wet as a well-wrung sponge – not too wet and not too dry. Composts need air (oxygen) and water to be healthy and filled with nutrients.

Regarding the 160-degree temperature recommended earlier, compost piles can also be as high as 170 degrees or as low as 120 degrees. This is not an exact science and, therefore, people don’t have to stick with one number, but 120 to 170 degrees is what most people aim for.

What If the Compost Is Too Cold?

Rather than getting too warm, a lot of gardeners find that their compost pile is having trouble getting warm enough. This can greatly slow down the composting process and in fact, it can take up to 12 weeks for the process to be completed, as opposed to roughly four weeks when the compost is hot enough.

People whose compost piles are way too cool can follow some of these techniques to raise the temperature of the piles:

  • Extend the compost pile so that it’s bigger and wider. This is a good idea if the compost is not in a bin but is instead sitting on the ground. Make the compost higher and about three to four feet wider on each side.
  • Make sure the compost is in the sun and in a warm location. This is one of the main rules when setting up a compost, but many people think it just doesn’t matter where the compost is placed.
  • Make sure the compost is well-insulated. This can be done by covering it with a tarp or adding additional brown materials such as sawdust or dry leaves. People who live in colder areas can also look into buying an insulated compost bin.
  • Raise the compost pile. If the compost is in a bin, this is easy to do. If the pile is sitting on the ground, it can still be moved but it may take a little ingenuity on the gardener’s part.

Remember, it isn’t just during the winter months that a compost may become too cool. It can happen at any time, so it’s good to know what to do about it when this happens.

Things That Cause These Problems

People who ask themselves, why is my compost not getting hot, are usually glad to discover that most of the things that cause a compost to stay too cool are easy to fix. For instance, below are some of the reasons a compost isn’t getting hot:

  • It doesn’t have enough bacteria.
  • It doesn’t have enough nitrogen.
  • It doesn’t have enough oxygen.
  • It is too dry.
  • It is too large.
  • It is too small.
  • It is too wet.

Fortunately, these things are easy to change so that a nice, healthy compost is ready sooner rather than later. Remember, in the end, “healthy” compost will be dark in color, crumbly in texture, and rather damp. People can tell this simply by looking at it and picking it up with their hands.

Following the tips mentioned above can help, and remember, if the compost is too cool, it will take longer to be ready to use. The warmer the compost is, the faster the composting process. It’s just that simple. Making sure the compost is between 120 and 170 degrees Fahrenheit, therefore, is extremely important.

Keeping a compost at the proper temperature isn’t difficult, as long as it is started properly by following all of the rules needed for a great compost in the end. Both being too warm and being too cold can present problems for a compost pile, but the good news is that the remedies for both of these challenges are very simple.