5 Signs Your Compost Is Ready for Use

when is compost ready
How do you know when compost is ready? Consider the compost's physical appearance. Unfinished compost will contain whole undecomposed kitchen wastes and a foul odor. Better yet, conduct the compost test with radish seeds. If one-third of the seeds sprout, then your compost is ready for use.

Unfinished compost can be extremely harmful to your garden plants and soil. To name a few, it can inhibit germination, deplete soil oxygen and nitrogen, and starve your plants to death.

As a result, it’s critical to ensure that your compost is completely ready. But the question is, “how do you know when compost is ready?”

Is the compost smelling earthy rather than ammonia or rotting food scraps? Is your compost a dark brown color, similar to garden topsoil, with a crumbly texture? Then your compost is ready for use.

But there’s more to think about.

5 Signs Your compost Is Ready

It’s easy to note if your compost is ready. To tell if your compost is ready to use, see if the following are evident in your compost pile.

  • If the composting method is hot composting, the compost temperature should be within the environmental temperature range. There shouldn’t be a significant temperature rise even after turning the finished compost.
  • The compost should have an earthy smell and not the smell of ammonia or rotting food waste.
  • The color of the compost should be dark brown.
  • You’ll notice a significant drop in volume when the compost is finished compared to the initial volume.
  • There shouldn’t be recognizable traces of decomposing kitchen waste. However, there can be some eggshells or nutshells because they do take a longer time to decompose. You can screen the compost to remove them, although they pose no harm. They’ll continue to decompose in the soil.

As a side note, the amount of time it takes compost to mature depends on the type of organic matter used. Remember that a compost pile has two components: green and brown materials. Eggshells and nutshells decompose more slowly than kitchen scraps.

Also, how you maintain your compost affects the time the compost takes to mature. For quick maturing, frequently turn the compost and ensure it has the right moisture content. It shouldn’t be too dry or too wet.

Finally, the readiness of the pile depends on the use of the compost. If you’re using the compost as mulch for top dressing, you don’t need to wait until all the organic matter decomposes.

However, if the compost is to be used for planting, then ensure the decomposition process is complete.

Testing the Compost Before Using It

As stated above, consider the physical appearance of your compost before using it in your garden. Secondly, perform the “finished compost” test.

The physical appearance of compost will determine whether or not it’s ready. Unfinished compost will contain whole undecomposed kitchen wastes such as fruit peels. Also, besides high temperature, unfinished compost has a bad odor of rotting garden waste.

For finished compost, you won’t find undecomposed organic materials; there shouldn’t be traces of kitchen waste or wood chips. The compost has an earthy smell with a dark brown color.

Just because your compost looks good doesn’t mean it’s ready.

You can perform the following test to verify the maturity of compost for greater accuracy.

Finished Compost Test

It’s not the quickest method, but it’s the surest way to check whether your compost is ready or not.

What you need:

  • A container
  • A sample of the compost pile
  • Radish seeds


Take some of the compost and put it into a pot. Count the number of radish seeds and plant them into the compost.

Wait for the seeds to germinate. If 75% of the seeds sprout, then the compost is ready to use.

What Happens if You Use Compost Too Early?

Your plant seeds won’t germinate or will quickly die after sprouting.


Unfinished compost contains phytotoxins which destroy the seed embryos, consequently killing the seed.

Immature compost needs nitrogen and oxygen for the microorganisms to break down the organic matter. Now, if you use the compost too early before this process is complete, the compost will absorb the nitrogen and oxygen plants require, depriving them of vital minerals.

Unfinished compost can transfer pathogens and pests to your garden. In hot composting, the high temperature makes it impossible for these pathogens and pests to survive. But if the compost is not left to mature completely, then these pathogens can find their way to the garden.

There are four cycles a compost needs to undergo before it’s ready for use.

They include:

  1. Mesophilic phase or cold composting phase
  2. Thermophilic or hot composting phase
  3. Cooling phase
  4. Curing phase

If the compost is used too early, the last stage, that’s the curing phase, is mostly affected. This phase is important as it adds microbes and earthworms into the compost, improving its richness.

Therefore, the consequence of not giving your compost adequate time results in substandard compost with little benefit for your plant and soil.

How Can You Tell If Compost Is Composting?

Check the temperature of the compost bin. If the temperature is high (over 100F), then the compost is not completely ready.

The presence of noticeable green and brown materials in the compost indicates that the compost is not yet ready for use.

Lastly, though complicated, you can tell if compost needs more time to decompose by performing the compost tea test.

Compost Tea Test

Take a sample of the compost and mix it with water. Sieve the mixture. The liquid is called “compost tea.”

Put some radish seeds in a small container and add the compost tea, just enough to wet the seeds.

The compost is not ready if the seeds don’t sprout or die after germinating. It’s still decomposing.

How To Speed Up The Composting Process

The composting process of compost is greatly influenced by how it is maintained.

  • The constant turning of the compost allows the microbes to multiply and break down the compost materials.
  • Never add new materials, for example, fresh kitchen waste, to your decomposing compost. It only slows the composting process and lengthens the time it takes for the compost to mature.
  • If you’re starting a new compost pile, adding already decomposing organic materials rich in microbes and earthworms will hasten the composting process.


Discovering composting as a way of life or even better, as nature’s way of recycling, Ana dedicates her time to trying out new methods of composting at home. Her goal is to share everything that she’s learned in the hopes that it will help others discover the amazing rewards of composting.

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