How long do you let compost sit before using it?

You just had your first batch of fresh compost. Looking at it makes you wonder, when would it be ready to use? You don’t want to use it prematurely. It is crucial to let compost mature for the appropriate time, or else it can ruin your plants.

How long do you let compost sit before using it? It would be best if you let compost cure or sit for at least 4 weeks. In some cases, curing is allowed to continue for a year to get high-quality manure. Proper maturing/curing of compost is very important. Immature compost can have detrimental effects on plants.

Knowing the vast time range required for curing, it can be confusing to decide if your compost is ready or not. Here we will explore various aspects that will make it easy for you to determine the usability and maturity of compost.

How can you tell if it is finished?

  • Texture: The materials that you added to the pile should not be identifiable. It should be crumbly and dark, like the topsoil.
  • Smell: The pile should not have any foul smell. It should have a mild earthy odour. Just like a forest on a rainy day!
  • Colour: After watching it, it should be clear why it is known as black gold!
  • Temperature: If you opted for hot composting, your pile should be back to normal temperature. A variation of 10F compared to the outside temperature is acceptable.
  • Volume: After the process of composting, the size of the pile shrinks by almost 50%.

Advantages of Curing 

  • The process of curing removes harmful substances like acids and pathogens. 
  • Immature compost continues to use nitrogen and oxygen. When it is applied to the plants, it competes with them for these valuable resources. This can hamper plant growth.
  • After curing, the chemical processes taking place in the compost are stabilized.

Factors influencing the rate – Internal and external 

The time it takes for your compost to mature depends on several factors. Let’s discuss them in detail.

  • Carbon Nitrogen Ratio: Carbon and nitrogen are essential for composting. Nitrogen is required for protein synthesis and reproduction, and carbon is needed for energy. The ideal carbon to nitrogen ratio is 25:1 to 30:1. If the ratio is lower than 20:1, All the carbon is used up without stabilizing the nitrogen resulting in ammonia production and smelly compost. If the ratio is more than 40:1, the compost lacks enough nitrogen to sustain microbial growth, considerably slowing down the process.
  • Air and Oxygen: Composting is mainly an aerobic process that requires an adequate amount of oxygen. In the absence of oxygen, the process becomes anaerobic, which is very smelly and slow. A minimum of 5% oxygen is needed in the pore spaces for composting. You can achieve this by frequently rotating the pile manually in a bin and mechanically in a compost tumbler.
  • Moisture Content: Good Composting requires 40% to 65% moisture content. If the moisture content is less than 40%, the entire process stops. If it is more than 65%, the water inhibits the airflow making the process anaerobic. A good way to check moisture is to take a handful and squeeze it. If you get water, it’s too wet, and if it feels dry, you need to add more water. As the process proceeds, the compost becomes dry, so you need to add water to it.
  • Temperature: Composting occurs in two temperature ranges Mesophyllic (50-105F) and Thermophilic (above 105F). Even though the process continues in the Mesophyllic temperature range but, most experts recommend the thermophilic range. It allows the elimination of pathogens, weed seeds and flies larvae. If you can’t achieve the required temperatures, try turning the pile. If it is still cold, check all the factors affecting the temperature. When you have carefully reviewed all the elements, it could mean that the compost may already be done. 
  • Size of Particles: Particle size is an important factor in deciding how quickly you will get the end product. Too large particles are harder to break down and hence prolong the process. Too small particles restrict the flow of oxygen, and they also slow it down. The ideal particle size diameter is 1/8th to 2 inches.
  • Time: The time required to complete the composting process depends on all the factors described above. Under ideal conditions, it can be finished in a few weeks, but generally, it takes 10 – 14 weeks

Best Uses Of Mature Compost 

After you are certain that you have the finished product, here comes the fun part. Using the resulting manure! Let’s talk about it.

  • Feed Potted Plants: You should not ignore your potted plants when you are distributing the manure. A little compost can boost their growth and keep them fed for weeks.
  • Use it as Mulch: Compost is a natural mulch. It can easily retain moisture and slowly release it to the plant. This also prevents the growth of wild weeds. A 3-6 inch layer works the best.
  • Grow your favourite vegetables – What’s the point of composting when you are still eating pesticide-ridden supermarket produce. Use the manure to grow your food. Melons, cucumbers, squash etc., flourish in nitrogen-rich soils. You should add the compost in the holes while planting the seeds. This gives essential nutrients to the plants right from the start.
  • Rejuvenate Garden Beds: If your garden beds can get a healthy dose of manure Twice a year, they provide a beautiful output. Once you sprinkle a layer of compost, the seasonal rains transfer the nutrients to the soil. Once inside the soil, the worms start working on it, integrating all that organic richness. 
  • Revive The Flowers – Add some manure to your flowering plants in the springtime. This gives them enough time to process all the mineral richness. You will love to see the results When the blossom after the winters.
  • Make Some Compost Tea: Before you make any assumptions, this tea is for the plants, not you! Just add some water into the compost and use it on your favourite plants. Compost tea is one of the best ways of delivering nutrients to plant roots. 
  • Increase Your Fruit Output: Fruits trees love the rich mineral constitution of compost. They especially like the high nitrogen content. Though you can use it any time of the year, it works best in spring or before the opening of the fruit buds.

Final Thoughts

Curing is a wonderful way to ensure the quality and safety of the compost. This is a crucial step in the process of composting and should not be ignored.


  • Wu, L., Ma, L.Q. and Martinez, G.A. (2000), Comparison of Methods for Evaluating Stability and Maturity of Biosolids Compost. Journal of Environmental Quality, 29: 424-429.
  • Michael Danon, Sharon Zmora-Nahum, Yona Chen, Yitzhak Hadar,
    Prolonged compost curing reduces suppression of Sclerotium rolfsii,
    Soil Biology and Biochemistry,
    Volume 39, Issue 8,
    Pages 1936-1946,
    ISSN 0038-0717,
  • Michael Danon, Ingrid H. Franke-Whittle, Heribert Insam, Yona Chen, Yitzhak Hadar, Molecular analysis of bacterial community succession during prolonged compost curing, FEMS Microbiology Ecology, Volume 65, Issue 1, July 2008, Pages 133–144,

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