In life generally, everything always returns to the soil, the food we eat, the plants and animals around us, and even ourselves because everything gets broken down into nutrients for the soil.
The role Composting plays in this circle is to help nature break down these materials faster and release the nutrients for use by plants.
Carbon, nitrogen, microorganisms, oxygen, and moisture are the 5 most important components in the Composting process, and carbon provides more than 50% of all compost. It is the basic building block of all materials, and it provides the energy source for microbes in the compost.
So today, we will let you understand the importance of carbon in the compost, materials rich in carbon, and how to check that your compost has the right amount of carbon in the mix.
Carbon In The Composting Process
Carbon is one of the most abundant elements in nature, and it forms the building block of most materials, from trees to rocks, graphite, man, and the likes; they all have carbon as their basic frame, which expresses its importance. Carbon still plays the same dominant function in the composting process.
In composting parlance, carbon-rich ingredients are called browns. Many people usually confuse this to mean that anything brown in color that you add to your compost pile is carbon, but this is not always the case because there is much carbon-rich compost ingredient of different colors.
Carbon-rich ingredients are usually fibrous or Woody in nature, which in technical terms can be said to have a high carbon to nitrogen ratio; these ingredients supply the carbon that provides the energy for the microorganisms which are considered the “workers” in the Composting equation to effectively convert ordinary materials into nutrients for the soil.
The right amount of carbon in your compost will ensure that these microbes have the energy to speedily convert organic matter to compost.
If you have ever seen a slurry-looking compost that stinks, you are dealing with a compost pile with less carbon-rich material for which the microbes are forced to produce energy anaerobically. So to keep your compost looking and smelling right, ensure you have enough brown compost ingredients in your pile.
What Does C: N Ratio In Composting Mean?
If you have been around gardeners who make and use compost, you have heard them say that you need to get a “30:1 C:N ratio for successful composting.
This is true because a balanced compost is expected to have 30 parts carbon and only 1 part Nitrogen. The good news is that mother nature will always help you tell if your C:N ratio is balanced by how your compost.
In reality, you might never be exact in composting using this ratio, but the closer you get, the better the compost you get.
Many people feel that the ratio of carbon to nitrogen seems too high. Still, the truth is that excess nitrogen in the compost gets lost as ammonia gas, resulting in a disgusting odor.
This smell tells you that you have more nitrogen than is necessary for your compost, so you have to introduce more carbon-rich compost ingredients.
Suppose the carbon content of the compost is higher than the 30 part ratio. In that case, you end up with cool compost ingredients that will take very long to yield compost because the nitrogen in a pile is not enough for the microbes population in the compost to grow optimally.
It isn’t easy to calculate how much carbon and nitrogen you have in your compost pile because, in reality, all carbon-rich compost ingredients do not have the same amount of carbon.
Secondly, the ratio stipulates the carbon to Nitrogen ratio of a compost pile and not the carbon-rich ingredient quantity nor the nitrogen-rich ingredient of the pile.
Even though there is a scientific means of determining this ratio from the different compost ingredients, we must say that you should rely on the sight and smell of the pile to tell if your compost has the right ratio.
This C:N ratio gradually decreases to about 10:1 with time as the compost gets ready. This is so because as the microbes act on these compost materials, they give off carbon dioxide as a by-product of respiration, and they also Incorporate some more of this carbon into their cells.
The Carbon To Nitrogen Ratio Of Some Compost Ingredients
Below are the average C:N ratios for some common organic materials found in the compost bin.
The Brown Compost Material
- Corn stalks 75:1
- Leaves 60:1
- Peanut shells 35:1
- Pine needles 80:1
- Sawdust 325:1
- Wood chips 400:1
- Fresh Sawdust 500-600:1
- Cardboard 350-550:1
- Shredded Newspaper 170:1
- Bark 130-1280:1
- Paper Towels 110:1
These compost ingredients are considered browns because of their high carbon content. It is advisable that when you add these browns, you mix them up so that you don’t use only materials that are too high in carbon like barks, cardboard papers, and sawdust; this will ensure that you get the right carbon ratio.
The Green Compost Materials
- Alfalfa 12:1
- Clover 23:1
- Food waste 20:1
- Grass clippings 20:1
- Hay 25:1
- Manures 15:1
- Vegetable scraps 25:1
- Weeds 30:1
These compost materials are considered green because they have a relatively lower carbon to Nitrogen ratio. Compost ingredients with a C:N ratio greater than 30:1is generally considered nitrogen-rich ingredients.
How To Tell If You Need More Carbon-Rich Ingredients In Your Compost
You can tell if your compost pile has less than the required carbon ratio if you notice that your compost seems wet. Your ideal compost pile should not be dry, but if you touch the compost pile, it should feel like a wrung-out sponge; it should ball up or clump.
This is because carbon-rich materials add structure to the pile. After all, they are fibrous; their importance is that it keeps the pile aerated and keep clods from forming.
The finished compost looks dark and crumbly and has an earthy smell. So if you squeeze your compost and water comes out, you may have more nitrogen-rich material than required.
Another sign of a carbon-deficient compost pile is the smell, which may attract bugs and pests like mosquitoes, maggots, and flies.
This happens because of the anaerobic activities of microbes in your compost. You can remedy this situation by drying out your compost and introducing more browns to your pile.
How To Know If You Need More Greens In Your Compost
It is not a very common problem to have fewer greens in a compost pile because green compost Ingredients are the most abundant of all compost materials.
However, if you are stuck with a carbon-high Compost, the microbes will eat too much and reproduce too much, but because they do not have enough nitrogen to build up the proteins they require, they, however, will start taking the nitrogen out of your soil if apply the compost to the soil in a process called nitrogen immobilization.
The impact they will have on the soil will be negative instead of improving it. You can tell that your compost has less nitrogen if the pile is decomposing slowly and not heating up.
Secondly, the pile will be dry, and the implication is that the microorganisms in a pile will not be able to act on the compost materials because there is not enough moisture to feed and reproduce. You can take care of this problem by adding your kitchen scraps and other greens to the compost.
What is a Good Source of Carbon for Compost
Here are some good sources of carbon that you can add to your compost:
1. Dry Leaves
Leaves are a good source of carbon for your compost, and the good thing about them is that it is readily available and has a relatively good carbon/nitrogen ratio of around 60:1. They also decompose very fast, which will help tour compost yield on time.
2. Paper Products
Most paper products are good for compost except those with toxic ink, adhesives, and those that have been plasticized.
Paper-like toilet papers, parchment paper, newspapers, and the likes are high in carbon. They easily decompose, especially if the paper type is light and has a large surface area like paper towels.
3. Cardboard
This is another good source of carbon, and it is useful for gardeners who do not have a lot of leaves, trimmings from Woody plants, or other carbon sources. But the snag with composting cardboard is that it is time-consuming.
4. Hay/Straw
The C:N ratio of straw and hay is about 50-150 :1, and it is a great addition to a Compost that is clumping together due to a lot of greens in a pile.
Even though straw and hay do not have a lot of nutrients in the compost, they help in aerating the compost, hence ensuring that the microbes have enough oxygen that they need for respiration.
5. Pine Needles
This is another excellent source of carbon, but the issue with pine needles is that they break down too slowly and so will not get your compost ready on time; they have the potential to slightly lower the pH, but the richness of its carbon is well worth it.
6. Plant Trimmings
Bush trimmings, old mulch, bark, chipped wood, and even dried weeds. These materials are carbon-rich, but they might contain some seeds that could be transferred to the soil when applied to the soil, especially if the compost is not hot enough.
7. Corn Cobs/stalks
This is another common source of carbon for your compost, especially for those who grow veggies in their garden; you can Compost almost everything left over after the harvest, especially the corn stalks and Cobs. They have a C:N ratio of about 60:1, making a good mid-range carbon source that requires a little more time to decompose completely.
8. Nut Shells
Most nuts are very rich in carbon, but they take a long time to completely turn into compost; in some cases, it can take years, except you shred them or put them in your food processor so that the compost will yield sooner. Pistachio shells, peanut shells, and most other husks are good sources of compostable carbons.
Conclusion
Nitrogen and carbon are the 2 major elements that every compost requires, and the ideal ratio of carbon to nitrogen in a Compost pile is 30:1 in favor of carbon.
Carbon supplies the requisite energy that the microorganisms in this microbiome use in converting ordinary organic matter into nutrient-rich compost.
Many materials around us can serve as a carbon source for our compost, including dried leaves, straw and hay, corn Cobs, and the like. You will know that your compost needs more carbon-rich compostable ingredients if it is soggy and stinky.
Helpful Links:
- Can You Compost Pineapple?
- How Do You Grind Compost?
- How To Compost Corn Plants
- Can Paper Towels Be Composted?
- Can I Compost Any Material I Find?
- Best Composting Grinder for Home Use
We trust this article helped you know a good source of carbon for compost. You may also want to check out The 4 Components of Composting?
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