Siobhan Devery had composted for two years before she admitted the bin at the end of her garden smelled consistently bad and had never produced anything she could use on her beds. Her neighbour's bin, started three months earlier, was already yielding dark, workable compost. The difference came down to three specific errors Siobhan had been making from the beginning.

The first error was adding only kitchen scraps. Vegetable peelings, fruit waste, and cooked leftovers are nitrogen-rich materials. Compost requires a rough balance between nitrogen-rich greens and carbon-rich browns: dry leaves, cardboard, paper, woody prunings. A bin fed only on kitchen waste becomes wet, dense, and anaerobic, which produces the characteristic bad odour and very slow decomposition.

The moisture and air problem

Siobhan's second error was never turning the pile. Oxygen is necessary for the aerobic bacteria that produce useful compost quickly. A pile that sits undisturbed for months can work eventually, but the lack of airflow slows decomposition by a factor of three or four and promotes the wrong bacterial processes.

Turning once every two to three weeks, even partially, changes the internal environment enough to make a measurable difference.

What actually accelerates decomposition

The third error was adding whole vegetable waste rather than cutting or tearing it. Surface area determines how quickly microorganisms can break material down. A whole cabbage leaf takes significantly longer than the same leaf torn into four pieces. This is one step, taking two extra seconds per item, that changes the timeline from eight months to three.