In our previous episode, we discussed on the fundamentals of composting and the types of
composting like the Aerobic and Anaerobic composting methods.
In today’s episode, we will discuss on the materials that can be used and those to be
avoided in composting, plus the Ideal Carbon Nitrogen and the Green to Brown Ratios.
Coming up!
Composting is a controlled and accelerated rotting down of organic matter into nutrient
rich compost.
Aerobic Composting uses the natural processes of rotting and decay by microorganisms in
the presence of oxygen and produces heat and hence its sometimes called hot pile composting.
Whereas Anaerobic or Bokashi composting is the job done mainly by microorganisms in the
absence of air which is more like fermentation process.
Aerobic Composting requires 4 things: Carbon, Nitrogen, Oxygen and Water in just the right
amount for proper composting.
Out of these, we need to provide Carbon and Nitrogen in the right ratio, what is known
as the C:N ration or Carbon Nitrogen Ratio.
Things that are rich in Carbon are called the Browns and those that are rich in Nitrogen
are known as the Greens.
To be correctly composted, a material needs to have the following two important characteristics:
1.
The waste material must be organic and biodegradable.
2.
The waste material must contain things that are liked by micro-organisms to feed on.
So what types of waste can we can use in aerobic composting method.
Firstly, let’s start with what we should NOT put onto our compost bin or compost heap.
So let lists the Don’t’s First: 1.
Glass, metal and plastics are obviously prohibited in both types of composting.
2.
Oil, fat, meat, fish or dairy products are avoided because of their tendency to attract
insects like flies and rodents.
But these products are allowed in Bokashi composting.
3.
Hard woody branches, stems or roots which take a very long time to decompose.
4.
Rubber bands, Latex condoms, diapers and other obvious stuff like metallic objects like for
example safety pins.
Having looked at the things to be avoided, now let’s look at what we can add, and there
are literally thousands to choose from.
Aerobic composting works best if these organisms are fed a mixture of carbon rich materials
known commonly as “Browns” and nitrogen rich materials known commonly as “Greens”
in proper ratios.
Let’s List the Browns First: Browns are mostly dried woody materials which are high
in carbon.
Without the browns your greens will decompose too quickly and turn into a smelly pile – that’s
called putrified pile.
Here’s the List of Browns: like dry fallen leaves, dried flowers, wood
chips, twigs, straw, shredded paper, shredded card board or paper cartons, like this and
also the toilet paper rolls, toilet paper or used napkins or facial tissues, coffee
filters and tea bags, cotton, sawdust, pine needles, Pencil Shavings, dried grass clippings,
peat moss, cocopeat or coconut fibers, used paper plates, nut shells, wine corks, toothpicks,
paper cupcakes, used match sticks, wood ash or ashes from the fireplace, coal, etc.
Now Let’s List the Greens: Greens are mostly wet materials like waste kitchen scraps mostly
vegetables scraps, fruit scraps, fresh grass cuttings, animal manure but not your cat or
dog poop, bird or poultry droppings and feathers, fleshy plants and leaves, flowers, tea and
coffee waste, egg shells, nail clippings (if no nail polish), human and animal hair, etc.
Having said that, now lets look at the Greens Vs Browns Ratio and the Carbon:Nitrogen Ratio.
The right mixture of greens and browns, known commonly in the gardening world as the Carbon-to-Nitrogen
ratio or C/N ratio, is important for proper composting.
We want Composting and not Putrefaction or rotting.
So what is the ideal C/N ratio for an aerobic composting?
Most experts suggest a CN ratio of 25 to 30:1, which means 25 to 30 parts carbon rich material
to 1 part nitrogen rich material.
High Carbon may result in too slow composting whereas high nitrogen may result in foul smelling
putrefaction.
HOW TO USE THE C:N RATIO?
Do not misinterpret this CN ration!
This ratio describes the chemical composition of a material and does not mean that you need
a volume of brown materials that is thirty times greater than the amount of green matter!
Don't make this mistake!
Here comes the Green to Brown Ration to our rescue.
You have to understand this carefully.
The Ideal Green to Brown Ration is 2:1 but it can also be 1:1 for those who are starting
to compost.
This means for one bowl of greens, you can add one bowl of browns.
Let me explain this.
Every material has its own C:N ratio, like for example Food Scraps has a Carbon:Nitrogen
Ratio of 17:1, meaning 17 parts Carbon to 1 part Nitrogen).
Saw dust has very high C:N ration of 500:1.
Hence this calculation depends on what you add to your compost bin and it gets more and
more complicated.
You can store this table for reference of C:N values of various materials.
For Ideal Composting – Do Remember these 2 Golden Tips:
• A 2-to-1 ratio of Greens to Browns is your best bet when creating a Batch Pile.
This will aid you in creating about a 30:1 C/N Ratio.
Adequate enough to get a hot pile.
• A 1-to-1 Ratio works well with the Add as You Go Pile as well as for the Batch Pile
and is safe for beginners.
This will aid you in creating about a 50:1 C/N Ratio, adequate enough to get a warm pile.
In our Next episodes of this composting series, we will demonstrate how to do Aerobic and
Anaerobic or Bokashi composting at home.
Please Like, Share and Comment below with your feedback and queries.
Happy Composting and Happy Gardening!