The sole aim behind conducting this experiment in my apartment was to check whether the compost culture sold by Gandhi Krishi Vignana Kendra (GKVK) located in North Bangalore can work just as good as any other culture/accelerator sold by vendors/innovators in the city.
Well, it does. At a much lower cost!
In general, microbial solutions–be it in powder form or liquid–are meant for accelerating composting. One should understand that composting will eventually happen but when we carry out the same in a controlled environment to compost large quantities, too many dos and don’ts sneak in.
Some of the concerns are foul odour, maggots in numbers one can’t simply handle and moisture seeping out of the containers or cement tanks. This is when neatniks bid a goodbye to composting itself and start looking for easy but hazardous solutions like automatic composters.
I used three plastic milk crates and one 300-litre barrel with holes. The barrel had a lid without sufficient holes in it.
GKVK sells various types of microbial consortia meant to serve different purposes to help the farming community. Although I have been using some of these for years now (please read this post), the compost culture remained untested. At the Department for Popularisation of Biofertilisers located on the GKVK campus where these microbes are sold, no one offered information on how to carry out composting using their culture. When they did, it was vague and incomplete. So thought of relying on my experience to get going.
I bought a cocopeat block of approximately 5 kgs, moistened it and added 5-6 spoonfuls of GKVK compost culture. (Ideally, it’s better to leave it unused for at least 10-15 days to help the microbes colonise the moistened, crumbly cocopeat.)
CRATE #1: Unshredded kitchen rejects. NO cocopeat. Only dry leaves. Spread a 5-inch-thick layer of dry leaves at the bottom. Mix the unshredded kitchen rejects with a spoon of compost culture. (A tip: To make sure the powder gets uniformly coated on the rejects, first mix it in a handful of cocopeat (or sawdust) and then mix it with the rejects). Fill the crate with this and add another 5-inch-thick layer of dry leaves on the top to prevent fruit flies hovering over it.
Note: I didn’t add cocopeat here as some residents who carry out composting in pits, cement tanks do not use cocopeat. Dry leaves are easily available and are a significant source of carbon.
CRATE #2: Unshredded kitchen rejects. Spread a 2-inch-thick layer of inoculated cocopeat. Mix the unshredded kitchen rejects with the cocopeat at 3:1 ratio (3 parts kitchen rejects : 1 part cocopeat). Fill the crate with this and add another 2-inch-thick layer of inoculated cocopeat on the top to prevent fruit flies hovering over it.
CRATE #3: Shredded kitchen rejects. Follow the same steps as in Crate #2.
BARREL: Drill the barrel with enough holes to ensure adequate aeration. A few at the bottom are essential to help excess moisture seep out. Add shredded kitchen rejects. Follow the same steps as in Crate #2.
All the four containers were placed in a dry, well-aerated and rodent-free room.
One week later…
Significant reduction in the quantity, reduced to half of its original volume. I could see fungal mold right below the top layer. The middle and bottom portions had a good deal of heat built up. The substrate turned black, almost.
In Crate #1, composting is progressing. No leakage of leachate despite the fact that there was no cocopeat in it to absorbs extra moisture. No maggots jumping out of the crate. When I lifted the crate, I saw a thin layer of moisture at the bottom and some worms.
In Crate #2, saw quite a few maggots. Substrate had turned black. Needed more work. The same was the case with the barrel.
Two weeks later…
Another 10-15% of reduction in the substrate quantity. Didn’t see further fungal mold build-up in any of the containers. Good amount of heat. No foul odour in any of the containers. Composting in Crate #3 which had shredded rejects was happening at a faster pace. Almost smelling like compost. But there still were semi-composted chunks in it. Needed more time.
Three weeks later…
Crate #3 done! The leftover semi-composted chunks can be thrown into the next batch. The remaining containers were doing good. One more week, the job will be done. What surprised me the most was Crate #1. No smell whatsoever. No fruit flies. No excess moisture seeping down. When held in hand, it had a good deal of moisture. Extremely pleasant smell. Since it was not shredded or treated with cocopeat, the substrate was sticky but not dripping wet. The dry leaves would take much longer to decompose but the rest of the kitchen rejects were undergoing transformation quite fast.
When Crate #2 And #3 were sieved, this is what we got after exactly three weeks. Almost 75% of the substrate turned into compost with around 25% of semi-composted material to be processed further. This will at least take a couple more weeks if you want to reduce it to a crumbly texture as this. Otherwise, you can generously feed the chunks to large bushes and trees in your garden. With constant watering, composting will keep on happening even as it releases nutrients to the roots and keeps the microbial activity on a constant uptick.
For nearly 40-50 kgs of raw material, I have used not more than 12-13 kgs of plain cocopeat and 5-6 spoonfuls of compost culture which is sold at Rs 80/kg. If you are handling greater quantities of kitchen rejects, then try using processed cocopeat bags sold in Majestic area, Bangalore. One particular vendor told me that unlike the blocks which can give you anything between 20-25 kgs of cocopeat when disintegrated, the bags have exactly 25 kgs of cocopeat with the right degree of moisture in it. This cocopeat is sold as a growth medium at Rs 150 per bag. You don’t have to deal with moistening the block and then crumble it to get started.
The actual outgo
At 1:3 ratio (inoculated cocopeat: kitchen rejects), to compost 100 kgs, you will be using 33 kgs of processed cocopeat at Rs 150/bag of 25 kgs each and a generous 100 gms of compost culture per day (Rs 8). The total cost/day works out to around Rs 208. Rs 6,240 per month (transportation cost excluded). If you are using cement tanks, instead of cocopeat, just add crushed dry leaves and a few spoons of culture each day. It works out even cheaper. But the turnaround time will be longer. For the next batch, you can use the same compost with a spoonful of culture thoroughly mixed. Make sure the compost always remains moist. Only then do the microbes remain alive.