Why Should Compost Be Hot?

by | Last updated on January 24, 2024

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If it's uncomfortably hot, it's at the right temperature. At 130 to 140 degrees,

microbes are breaking down organic matter and reproducing at high rates

. This temperature is also hot enough to kill most weed seeds and harmful bacteria in the pile.

Should my compost be hot?

The hot composting process needs to reach an optimum temperature of

55-65 °C (131-149 °F)

. … This bacteria appears when the gets too hot, over 65 °C and short of oxygen, and it disappears when the temperature drops and aerobic composting bacteria take over once again.

Why do you want a compost pile to get hot?

Compost heat is produced as a by-product of the microbial breakdown of organic material. … Compost managers strive to keep the compost below about

65°C because hotter temperatures cause the beneficial microbes to die off

. If the pile gets too hot, turning or aerating will help to dissipate the heat.

When should I turn my compost hot?

The rule of thumb for an active, hot pile is

every three days until it stops heating up

. Some over-enthusiastic composters rush out after a day and turn the pile. This is a bit too much of a good thing.

How does temperature affect compost?

Temperatures within compost piles affect

microbial growth and activities

, and hence the rate at which the raw materials decompose. Higher temperatures result in faster breakdown of organic materials, destroy weed seeds, and kill pathogens. However, excessively high temperatures (>160 ̊F) can inhibit microbial activity.

What is too hot for compost?


Above 160°F

, compost is too hot. Few thermophilic organisms are able to get much done when their environment is too hot. If left above 160°F, bacteria will cease active decomposition, which in turn will render the pile inert. [Tweet “Above 160°F, compost is too hot.

What will make compost break down faster?

Turning the pile frequently allows more oxygen to the microorganisms that are creating your compost, which in turn accelerates decomposition.

Aerating it every couple

of days will create compost faster than aerating it weekly. Water the pile in dry weather to keep it damp, but not soggy.

Can a compost pile catch on fire?

Excessive temperatures in compost can cause a spontaneous combustion, but this is very

rare

even among over-heated compost piles. Properly aerated and moist compost piles, no matter how hot, are not dangerous. Even hot compost bins that are fairly enclosed will not catch fire if they are tumbled and kept moist.

What will happen if you left the compost too long?

If compost is left too long,

it will still generally be usable

. However, it may lose some of its potency if constantly exposed to the elements. Compost will often just become even finer as the microorganisms continue to work.

Why is my compost not hot?

If the compost pile is not heating up, then

the pile is too wet or too dry or there is not enough green material (or nitrogen) present

. If too wet, the material should be spread out to dry. If too dry, add moisture to make it “spongy”. … Good luck on your compost.

What happens if you don't turn compost?

Turning the pile periodically to add more oxygen kicks it back into gear. If you don't want to turn your pile frequently (or at all), don't worry.

Compost will still make itself

, it'll just take longer.

How often should I turn compost?

The average composter turns the pile

every 4-5 weeks

. When turning the compost pile, make sure that materials in the center are brought to the outsides, and that materials from the outside edges are brought to the center.

How long does it take for compost to turn into soil?

Decomposition will be complete anywhere from

two weeks to two years

depending on the materials used, the size of the pile, and how often it is turned. Compost is ready when it has cooled, turned a rich brown color, and has decomposed into small soil-like particles.

At what temperature does compost combust?

Compost temperatures must reach

300°F to 400°F (150°C to 200°C)

for spontaneous combustion of materials to take place.

How do I increase the heat in my compost?

  1. Use small material in the compost pile. …
  2. Combine green nitrogen-rich materials, such as grass clipping and plant trimmings, with brown carbon-rich materials, such as dead leaves and sawdust. …
  3. Sprinkle 1 inch of healthy garden soil between the layers in the pile.

Can you plant in hot compost?

The thing I love about hot composting is you're harnessing the natural heat generated when plants break down and one of the great spin-offs of this is

you can compost almost anything

because the heat will cook any weeds and any infected plant material that you'd normally have to throw in the bin.

David Martineau
Author
David Martineau
David is an interior designer and home improvement expert. With a degree in architecture, David has worked on various renovation projects and has written for several home and garden publications. David's expertise in decorating, renovation, and repair will help you create your dream home.