Leaf Mould Calculator — Estimate Leaf Mould Yield
Calculate how much leaf mould you can make from collected autumn leaves.
How We Calculate This
Fallen leaves shrink by roughly two-thirds as they rot, so the finished leaf mould is about a third of the fresh-leaf volume you started with (RHS guidance: a quarter to a third).
Beech and mixed deciduous rot fastest — about 30% yield in ~12 months. Tougher oak gives ~28% in ~18 months. Leathery conifer needles lose the most volume and decay slowest — about 25% yield over 2-3 years (RHS), and the result is acidic, so keep needles in a separate heap for ericaceous plants.
Frame the heap (or bin/cage) at least 10% larger than the fresh leaf volume so you can pack leaves down, keep them moist, and let air circulate. These yields are indicative — actual reduction varies with how wet the leaves are and whether you shred them first.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.