Green Manure


Green manures are short-term crops that are specifically grown to be dug back into the soil, adding organic matter and nutrients. The main reasons for growing green manures are:

  • To help break-up heavy soils and improve drainage>
  • To suppress weeds
  • To add organic matter to the soil to improve its structure and fertility
  • To help make nutrients available to plants that are grown in the soil afterwards
  • To prevent nutrients being washed through the soil in winter
  • To protect the soil from compaction caused by heavy rains

Here’s how to produce green manure:

  • Sow either by broadcasting (thrown randomly) or sown in rows
  • Prepare the ground as you would for any other crop
  • The crop can be dug into the soil as soon as it has put on some growth but the longer you leave it the greater the benefits. However, it must be dug in before it flowers and set seed or before the stems go woody
  • Use a sharp spade, shears, nylon-line trimmer or even a rotary mower to chop down the green manure, and then incorporate everything (including the roots) into the soil as you dig
  • Leave three weeks after digging in a green manure before planting or sowing in the same ground

The main drawback with green manures is that nothing else can be grown in that area whilst it is growing so it is best to choose an attractive, useful plant such as Lupins.

There is a range of good green manure crops; which you choose will depend on when you intend to sow it and how long you are prepared to leave it growing before incorporating it into your soil. Here are some examples:

Common Name Latin Name When to Sow Growing Time When to Dig In
Alfalfa Medicago sativa Late Spring 3-24 Months Any Time while Fresh
Buckwheat Fagopyrum esculentum Spring to Late Summer 2-3 Months Any Time before Flowering
Alsike clover Trifolium hybridum Spring to Summer 2-24 Months Any Time while Fresh
Crimson clover Trifolium incarnatum Spring to Summer 2-6 Months Just before Flowering
Essex red clover Trifolium pratense Spring to Summer 2-24 Months Any Time while Fresh
Fenugreek Trigonella foenum graecum Spring to Summer 2-24 Months After Flowering before pods develop
Fava beans Vicia faba Autumn 4 Months Any Time before Flowering
Italian ryegrass Lolium multiflorum Early Spring 2-3 Months Any Time before Flowering
Lupin Lupinus angustifolius Spring to Early Summer 2-3 Months Just before Flowering
Mustard Sinapis alba Spring to Early Autumn Up to 2 Months Any Time before Flowering
Phacelia Phacelia tanacetifolia Spring to Early Autumn 2-6 Months Just before Flowering
Rye Secale cereale Late Summer to Autumn 4-6 Months Just before Flowering
Trefoil Medicago lupulina Spring to Summer 12 Months Any Time while Fresh
Winter tare Vicia sativa Spring to Late Summer 2-6 Months Any Time before Flowering

Buy Green Manure seeds from Suttons:

  • Green Manure Mix Seeds – adds nutrients and moisture to soil. Price: £2.99
  • Organic Green Manure Red Clover Seeds – helps improve fertility. Price: £2.45
  • Organic Green Manure Phacelia Balo Seeds – dense, quick-growing foliage. Price: £2.45

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