In our previous two posts we discussed on the fundamentals of composting, Types of Composting and the materials that can be added and those that are prohibited in compost bin plus we also discussed on the CN ratio and the Greens vs Browns Ratio. In this post, we will demonstrate how to do Bokashi composting correctly to get that perfect organic compost at home – with no foul smell and within a short period of time plus you also get a glass or two of nutrient rich compost tea which you can dilute and water your plants.
Bokashi composting is anaerobic method of composting, meaning it happens in the absence of air or oxygen and is actually a fermentation process carried out by special anaerobic microorganisms, first developed by a Japanese professor – Dr. Teuro Higa. The term Bokashi is a Japanese word that means “fermented organic matter.” This method was mainly developed to recycle wet nitrogen rich kitchen waste quickly, unlike the conventional aerobic composting which takes atleast 4 to 6 weeks to form complete compost.
So, What are the materials that best work with this type of composting. Anything can be composted, but the carbon rich browns like dried leaves, saw dust, grass clippings, paper, card board, etc will take a long time to decompose in this method or might even halt or fail the process of composting. Anaerobic Composting works best with nitrogen-rich materials as they are mainly wet – the kitchen scrap including left over cooked or raw food, vegetable and fruit scraps, cooked or uncooked meat and fish except bones – this is actually avoided in aerobic composting and vermicomposting, but this is the beauty of Bokashi composting! You can also add egg shells, tea and coffee grounds, tea or coffee bags and other stuff which is common for greens in aerobic composting as discussed in our previous post. Avoid adding large seeds like mango seeds, bones, rubber bands, condoms, metallic objects and so on.
Well, now Let’s learn Bokashi step by step. One thing to note before we start is: You can either do batch composting or one shot composting. In batch composting you add your kitchen waste on a day to day basis, opening the compost bin lid. I recommend One shot composting, like Add it, close it and forget it. One Simple Tip for you: Collect your daily kitchen waste in bags and store the waste in your refrigerator.
Step 1: The Container: This is typically any air tight container called Digester. You can use any barrel or a bucket with a lid which can seal it perfectly. This container should have a tap at the bottom to collect our nutrient rich compost tea once or twice in a week.
Step 2: Preparing the Bottom: First of all place about 20 to 30 gms of jaggery or molasses at the bottom of the container. This accelerates the fermentation process and is a food for our hard working microbes. Then Place the plastic grate at the bottom of the bucket with the knob facing upwards. This space of about 3 inches is required for the fluids to collect at the bottom which we drain out as the Bokashi Tea. Then Make sure the tap is closed and then Place a piece of newspaper over it.
Step 3: Bokashi Bran: or Bokashi powder is a magic ingredient in this system. This is a vegan stuff and contains the essential microorganisms to perform the composting process quicker than the conventional method of composting. This powder is inexpensive and easily available.
Step 4: Layering: First layer you sprinkle the bokashi bran over the bottom – two table spoons. Then you add a 1 to 2 inch layer of kitchen waste over this. For every 1 – 2 inch waste, sprinkle atleast two tablespoons of bokashi bran. Then again add 1 – 2 inch kitchen scraps and then again sprinkle bokashi powder. Make sure you chop large chunks of waste into smaller pieces for faster composting. Crush and add egg shells.
Step 5: Compression: In this step you compress the layers as and when you are adding the waste layer by layer. This will displace out the air pockets which may be present in between the waste. This is also an important step for successful smell free composting.
Step 6: After your finish multiple layers. Add a thick layer of bokashi powder like about 3 tablespoons and take and extra step to keep it air tight. Place a piece of cardboard on top of the layers and press it. Then Finally Close the Lid properly to make sure there is no chance of air entry.
Step 7: Location: You can keep it indoors or in any location where there is no sunlight.
Step 8: Collecting Bokashi Tea: This tea must be collected every 3 or 4 days to avoid foul smell and composting failure. This tea can be used as a liquid fertilizer for your plants. It must be diluted with water at a 100:1 ratio, that’s 100 parts water to 1 part bokashi juice, that’s approximately 2 teaspoons of juice for every litre of water. Mix well and water your plants to give them an instant supply of nutrients.
Step 9: Leave it Undisturbed for at least 15 days before you harvest. But don’t forget to collect the bokashi tea twice in a week.
Step 10: Harvesting: This is the only drawback of Bokashi. Just as pickled onions or mangoes are still the same size and shape, your pickled food scraps preserve their looks, unlike aerobic composting where the stuff shrinks considerably during decomposition. But the advantage is its high nutritive value, but the harvested bokashi after 15 to 20 days needs further processing and cannot be added directly to plants. You need to dig a trench in soil and add this final product and cover it with atleast 6 inches soil. Allow another 3 to 4 weeks for final processing and then plant over it or use this finished compost on your plants. If you also have the conventional aerobic composting going on, you can just dump this into it for faster and perfect processing.
In our next post we will demonstrate conventional aerobic composting method, step by step.
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 it is 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:
- Glass, metal and plastics are obviously prohibited in both types of composting.
- 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.
- Hard woody branches, stems or roots which take a very long time to decompose.
- 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. The micro-organisms and even macro-organisms like earthworms need to have a balanced diet and just like animals or humans they need “energy” in the form of food to survive. This energy is supplied to them by carbohydrates which contain Carbon. But micro-organisms also need proteins in the form of Nitrogen and also Phosphorus. 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 posts of this composting series, we will demonstrate how to do Aerobic and Anaerobic or Bokashi composting at home.