Green manures

Steve and Val Bradley outline the benefits and challenges of using green manures

- Steve and Val Bradley

GREEN manuring is the practice of cultivating certain fast-growing plants that can be used to improve and maintain soil structure, help retain soil fertility, reduce the loss of nutrients, suppress weeds and, in some cases, help to combat soil-borne pests and diseases.

Multiple usage 

The plants used as green manures are usually grown with the sole aim of incorporating them into the soil where they are growing. Although often regarded as having a place only in the vegetable or fruit garden, they fit just as well into a border since some provide a splash of colour when they are in flower. They are also useful for maintaining healthy border soil in the greenhouse, polythene tunnel or raised bed.

Questionable claims 

Perhaps the biggest question mark over green manures is the claim that these plants help to maintain – or even improve – soil structure. Certainly, their roots help to improve the structure of the soil, but the counter argument is Al that any form of cultivation, including digging, has the effect of damaging the soil’s natural structure.

The benefits obtained from green manures that are incorporated into the soil can depend on timing.

Best time to incorporate