Gardeners are being urged to avoid leaving fallen leaves on their lawns this autumn, as the Royal Horticultural Society (RHS) warns the practice can damage grass and lead to brown patches.
In a recent TikTok video, RHS horticulturalist Becky Mealey said: “Before you rake up those leaves, there’s something your garden needs you to know.”
Why leaves harm lawns
Fallen leaves left on lawns can cause more harm than good by blocking sunlight, trapping moisture and restricting airflow, which suffocates the grass and encourages fungal growth. Grass needs light to perform photosynthesis and produce energy, and a thick layer of leaves blocks that light, weakening and discolouring the blades underneath.
Wet leaves can also trap moisture in the soil, creating a heavy, dense barrier that stops the ground from drying out. This soggy microclimate promotes moss growth and decay in both the grass and soil, while also preventing airflow to the ground.
Where to put the leaves instead
Mealey advised that leaves falling directly onto soil can be left alone, but they should be moved off lawns and paths. She said: “Leave some under trees and shrubs, but remove them from lawns, paths and small plants where they can block the light.”
Moving the leaves to patches of soil under trees and shrubs allows them to act as a layer of mulch, improving soil quality, helping the soil retain moisture and providing shelter for wildlife.
Making leaf mould
Gardeners can also use fallen leaves to make leaf mould, a natural soil conditioner. Mealey recommended using a lawnmower to shred the leaves so they break down faster, then storing them in a hessian sack or leaf cage.
“Make sure they’re damp, leave them somewhere cool, and let nature do the rest. Unlike compost, you don’t need to turn it,” she said. After around a year, the partially decomposed leaves can be used as mulch to help soil retain moisture, particularly in dry conditions. “Leave them for two years or more for a finer material that helps to improve soil structure,” she added.
Mealey concluded: “So this autumn, don’t treat fallen leaves like waste, they’re a valuable resource for the garden.”
