SOW GREEN THIS AUTUMN

Covering the soil with a green manure in winter offers many benefits and this is a good time to sow hardy types, says KG editor Steve Ott

- Steve Ott

Green manures are quick-growing crops sown mainly for the benefit of the soil. They act as a kind of green blanket that both protects and improves the soil and can also encourage the essential life it contains. They are usually sown on to bare land that isn't currently supporting edible crops.

They can be used all year round but are especially important in winter to cover soil that has been working hard all summer and is now empty and awaiting spring sowings. Some gardeners like to follow the traditional method of digging and leaving the soil exposed over winter for the frost to make it nice and crumbly for sowing. However, this leaves it vulnerable to 'leaching' - valuable nutrients being washed down and out of the reach of next season's crops and into the water table below where it can potentially add to pollution problems.

Green manures instead form a green umbrella over the surface, protecting it but also absorbing nutrients as they grow, locking them away in leaves and stems. The roots help to channel the soil, improving structure and, depending on type, bringing nutrients up from deep below into the reach of other crops.

September-sown green manures grow slowly over winter and then, before they become too established in spring, are chopped and dug into the soil in which they have grown, so putting back those nutrients, plus some they will have made. They also add humus as they break down and help to feed soil life in preparation for another season of sowing and planting.

ROUGH AND TOUGH

At this time of year it is important to choose only hardy green manures that can withstand the cold and frost, but thankfully there are a few, all hardy annuals, that can shake off all the winter may throw at them.

FIELD BEANS