Home composting fails for one reason nine times out of ten: too much wet kitchen waste and not enough dry material. Fix that ratio and the smell, the flies and the sludge all disappear together.
What you need
A bucket of about twenty litres with a lid, a dozen holes drilled around the sides for air, a bag of dry leaves or shredded newspaper kept beside it, and a stick.
The method
Every time you add a handful of wet waste — peels, tea leaves, coffee grounds, stale rice — add two handfuls of dry material on top and stir with the stick. Keep the lid on. That is the whole method. No starter culture, no buttermilk, no cow dung required, though a scoop of finished compost or garden soil at the start speeds things up.
What to leave out
Meat, fish, milk, oil and cooked food with masala all attract flies and smell. Citrus peel and onion skin are fine in small quantities. Nothing plastic, nothing glossy, no tea bags with nylon mesh.
When is it ready?
Six to ten weeks in warm weather. Finished compost is dark, crumbly and smells of forest floor rather than of the kitchen. Sieve out anything recognisable and throw it back in for the next batch.
How to use it
A generous handful worked into the top inch of each pot every three or four weeks is all a balcony garden needs. Nothing you can buy will do more for your plants, and it costs nothing at all.