Carbon-Nitrogen ratio in compost

CONTROL OF THE CARBON-NITROGEN RATIO IN COMPOSTING

The Carbon-Nitrogen ratio of the compost is a very useful indicator to evaluate the development and quality of our compost. The value of this C / N ratio varies according to the authors, and is estimated between 25: 1 and 40: 1. This means that there are 25 or 40 parts of carbon to 1 of nitrogen.

 

 

WHAT HAPPENS IF THE CARBON-NITROGEN RATIO IS TOO HIGH OR TOO LOW?

If composting stores too much carbon-containing elements, it will be released in the form of carbon dioxide into the atmosphere. The fermentation in this case will be slow and low temperature and it will take longer to obtain the final compost .

In the case of excess nitrogen content, ammonia will be discharged into the atmosphere, emission of unfavorable odors and high temperatures.

HOW TO IDENTIFY THE CARBON-NITROGEN RELATIONSHIP OF COMPOST?

There are defined parameters to identify and control the carbon-nitrogen relationship of the compost. We have discussed one of them before.

  • The compost temperature is very high.  The C / N ratio is low (high nitrogen content).
  • The compost pile gives off an unpleasant ammonia smell. The C / N ratio is low.
  • Great presence of fauna. Worms, flies and other insects. The C / N ratio is low.
  • The composting process is slow, almost stopped. The C / N ratio is high (high carbon content).

To control the Carbon-Nitrogen relationship in the compost, the following table is shown with the carbon-nitrogen indices of each one.

 

ElementC / N ratio
Food waste15/1
Chunks or chips of wood200-500/1
Straw40-100/1
Paper200/1
Manure5-25/1
Coffee residues20/1
Fruit waste35/1
freshly cut legumes20-25/1
Autumn pruning branches30-80/1
Humus10/1
Sheets40-80/1
Bird manure5-15/1
Grass17/1
Diary paper400/1
Wheat straw100/1
Showing from 1 to 15 of 15 records

Mariano Bueno wrote a great book on composting, where he teaches us all the steps we must know to make the best compost possible. It’s titled How to Make Good Compost .

Welcome to The GardenPure! My name is Ryan Heagle, and I’m the founder of The GardenPure, I spent the first part of my adult life teaching and then living in Australia in various business ventures, the first of which was a business devoted to the sale of house plants.  I am now a full time blogger. I am a self taught gardener.

Ryan Heagle

Welcome to The GardenPure! My name is Ryan Heagle, and I’m the founder of The GardenPure, I spent the first part of my adult life teaching and then living in Australia in various business ventures, the first of which was a business devoted to the sale of house plants.  I am now a full time blogger. I am a self taught gardener.

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