My first attempt at composting kitchen waste took eleven days to become something I could smell from inside the flat with the balcony door shut. Not the earthy smell people describe in gardening articles — a sour, sharp, drain-like smell. When I finally opened the bin, the contents had collapsed into a grey-brown sludge with a film of moisture sitting on top. There was no crumbly texture, no warmth, nothing that resembled compost. I tipped the whole thing into a garbage bag and started over.
I did that three times before I understood what was actually happening. This article is what I wish someone had told me at the start, because almost every composting guide I read had been written for a climate where the ambient air is dry enough to forgive a lot of mistakes. On a humid Indian balcony, those same instructions produce sludge.
What "Slimy" Actually Means Biologically
Composting is aerobic decomposition — microbes breaking down organic matter while consuming oxygen. When there is enough air moving through the pile, you get heat, a pleasant earthy smell, and a crumbly end product. When oxygen runs out, a completely different set of anaerobic microbes takes over. Those organisms produce organic acids and sulphur compounds instead. That is the sour smell. The sliminess is the physical result: material breaking down into a dense, waterlogged mass with no air pockets left in it.
So the question is not "why is my compost slimy" — the question is "why did my pile run out of air." In Indian conditions there are three answers, and I was making all three mistakes simultaneously.
Mistake One: Almost All My Input Was Wet Green Waste
My kitchen bin was, on any given day, roughly this: vegetable peels, tomato ends, coriander stems, onion skins, tea leaves from about six cups of chai, and fruit peel. I was proud of how little I was throwing away. What I did not register is that nearly all of it was high-nitrogen, high-moisture "green" material.
Composting needs both nitrogen-rich green material and carbon-rich brown material — dry leaves, cardboard, sawdust, dried coconut husk, shredded paper. The browns are what create structure. They hold the pile open so air can move through it. Greens alone, especially wet greens, pack down into a dense layer the moment they start softening.
I weighed my inputs for one week out of curiosity. It came to about 4.1 kg of kitchen waste and roughly 200 g of dry material — some newspaper I had torn up as an afterthought. That is nowhere near what is needed. The standard recommendation is a carbon-to-nitrogen ratio around 25-30:1 by weight of carbon to nitrogen content, which in practical volume terms works out to roughly two to three parts brown material to one part green.
By volume, I had been running approximately one part brown to eight parts green.
Mistake Two: I Was Adding Water
This one still embarrasses me. Every guide I read said the pile should be "as moist as a wrung-out sponge," so I would check the bin, feel that the top layer looked a bit dry, and pour in a mug of water.
What I had not accounted for is that vegetable peels are already 80-90% water by weight. In a humid environment where ambient relative humidity sits between 60% and 80% for months at a stretch, that moisture does not evaporate out of the pile the way it would in a dry climate. It stays. Then it accumulates, because every new batch of peels adds more.
The dry-looking top layer was misleading me. It was dry because it was exposed to air — two inches down, the pile was saturated. I only realised this when I started digging into the middle with a stick before adding anything, instead of judging by the surface.
Since then I have added water to a compost bin exactly twice in two years, both times in peak May when the daytime temperature crossed 43°C and the pile genuinely had gone dry through its full depth.
Mistake Three: My Bin Had Drainage Holes But No Airflow
I started with a plastic bin with holes drilled in the bottom. Water could get out, technically, but there was no path for air to move sideways through the material. The bin was 32 cm across and I was filling it to about 25 cm deep. That depth of dense, wet material has no chance of staying aerobic in the middle, no matter how many holes are in the base.
Air needs to enter the pile from the sides, not just drain out the bottom. This is why traditional compost heaps work — they are exposed on all sides. A sealed container needs help.
What Actually Fixed It
The fix had four parts, and I introduced them one at a time across two more attempts so I could tell what was doing the work.
1. I Started Stockpiling Brown Material Separately
This was the single biggest change. I keep a separate bag on the balcony — an old rice sack — filled with dry material. Into it goes: dry fallen leaves swept from the building compound, torn cardboard from parcel boxes with the tape removed, brown paper bags, the dry outer husk from coconuts, and shredded newspaper.
Every time I add kitchen waste to the compost bin, I add roughly twice that volume of brown material on top of it and mix. Not measured precisely — I use a mug for the kitchen waste and add roughly two to three mugs of dry material.
The difference was visible within four days. The pile stopped looking wet on the surface. When I dug into it, there were visible air gaps between pieces of cardboard and leaf. It felt springy rather than dense.
2. I Stopped Adding Water Entirely
Instead of watering, I now do the squeeze test on material from the middle of the pile, not the top. Take a handful, squeeze it in a fist. If a few drops come out, moisture is right. If water runs, there is too much — add more dry material. If nothing comes out and it crumbles apart immediately, then and only then does it need water.
Over two years, my pile has needed water twice. It has needed extra brown material dozens of times.
3. I Switched to a Bin With Side Ventilation
I drilled 8 mm holes in a grid pattern up all four sides of a plastic bin — roughly 40 holes total, spaced about 6 cm apart, starting 5 cm from the base and going up to the rim. This was a ten-minute job with a drill borrowed from a neighbour.
The other thing I changed: I stopped filling it deeper than about 20 cm of active material. If I have more waste than that, it waits a day, or it goes into a second bin. Depth is what kills airflow in the middle.
4. I Turn It Every Third Day
Turning means mixing the pile so the outer material moves inward and vice versa. I use a piece of PVC pipe as a stirrer — push it down, lever it around, lift and fold the material over.
Every third day is what works for me. Daily was unnecessary and I lost interest in doing it. Weekly was too infrequent and I would find a sour patch developing in the centre. Three days is short enough that anaerobic pockets do not get established.
My Current Timeline: What 25 Days Looks Like
Since making these four changes, my composting cycle has been consistent. Here is the log from a batch I tracked closely, started in early October when the daytime temperature was around 32°C and overnight around 22°C.
Days 1-3: Fresh material still recognisable. Peels visible, cardboard visible. No smell when the lid is opened beyond a faint vegetable smell. Pile feels loose and springy.
Days 4-7: The first real change. Material has settled by roughly a third in volume. When I push a hand into the middle, it is noticeably warm — not hot, but clearly warmer than the surrounding air. Vegetable peels have gone soft and darker. Cardboard edges are becoming soft and starting to break down where they were in contact with wet material.
Days 8-14: Peak activity. This is when the pile is warmest. Individual items become hard to identify. Colour shifts from mixed browns and greens to a fairly uniform dark brown. Smell, when I open the lid, is earthy and slightly sweet — the smell people mean when they say compost smells good. Volume has now dropped to roughly half of the original.
Days 15-21: Cooling down. Material looks like coarse soil with some recognisable fibrous bits — usually coconut husk and thicker stems, which take longer. Texture is crumbly. Warmth is fading.
Days 22-25: Finished, or close enough to use. Dark, crumbly, smells like forest floor. Volume is roughly 35-40% of what went in. There are always a few pieces of coconut husk and thick stem that have not fully broken down — I sieve those out with a kitchen colander and throw them back into the next batch as a starter.
In peak summer (April-June, daytime above 40°C) this timeline compresses to around 18-20 days, though the pile needs checking more often for dryness. In winter (December-January, overnight around 8-10°C) it stretches to 35-40 days and stays noticeably cooler throughout.
What I Do Differently in Monsoon
Monsoon is when composting on an Indian balcony gets hardest, because the ambient humidity is so high that the pile cannot shed moisture at all. Two changes make the difference:
First, I move the bin fully under cover — not just out of direct rain, but where wind-blown rain cannot reach it. A bin getting even a small amount of rainfall every day will not stay aerobic.
Second, I increase the brown material ratio significantly — closer to three or four parts brown to one part green instead of two. In practice this means I compost less kitchen waste per day during monsoon, because my brown material stockpile becomes the limiting factor. Dry leaves are also harder to collect when everything outside is wet, so I stockpile cardboard specifically ahead of the season.
My monsoon batches take around 30-35 days rather than 25, and the finished product is slightly wetter than I would like. That is acceptable. What matters is that it does not go anaerobic.
Signs the Pile Is Going Wrong (Catch It Early)
These are the warning signs I watch for now, in the order they usually appear:
Surface looks wet or shiny. The earliest sign. Add dry material and turn immediately — at this stage it is a five-minute fix.
Sour or vinegary smell on opening the lid. Anaerobic activity has started but is still localised. Turn thoroughly, add a generous amount of brown material, and check again in two days.
Material feels dense and heavy when stirred. Structure has collapsed. This needs a lot of brown material — I would add equal volume to what is already in the bin, mixed through completely.
Liquid pooling at the bottom or draining out. Serious excess moisture. My approach here is to spread the whole pile out on newspaper for a few hours in shade to shed moisture, then rebuild it with plenty of dry material layered through.
Ammonia smell. Different problem — too much nitrogen, not enough carbon. Same fix: brown material.
The pattern in every case is the same. Almost every kitchen-waste composting problem in a humid climate is solved by more carbon and more air, and almost none of them are solved by water.
What I Would Tell Someone Starting Today
Set up your brown material stockpile before you start collecting kitchen waste. That is the sequence I got wrong. If you begin composting with a bin of peels and no dry material on hand, you will be behind from day one and you will spend the first two weeks fighting sludge.
Start smaller than you think you need to. A 20 cm depth of material in a well-ventilated bin will compost reliably. A 40 cm depth in the same bin will go anaerobic in the middle almost regardless of what else you do.
And treat the moisture instructions in most composting guides as written for a drier climate than yours. "Moist as a wrung-out sponge" is still the right target — but in Indian humidity, you will reach it and exceed it from the kitchen waste alone.
A Note on This Article
Everything above comes from my own composting on a north-facing apartment balcony in north India, across roughly two years and, by my count, somewhere over twenty completed batches plus the three failed ones at the start. The timeline figures are from my own written log, not estimates. Temperatures cited are ambient air temperatures on those dates, measured on the balcony.
Your results will differ with your local humidity, your specific waste mix, and your bin. The principle — carbon and airflow before water — has held up across every batch I have run. If you try this and something behaves differently in your conditions, I would genuinely like to hear about it; you can reach me through our contact page.
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