Green Manures – sow now!

Phacelia tanacetifolia – very attractive to bees and beneficial insects.

If you’ve never grown green manures before then give them a try this autumn. Invaluable crops for the vegetable patch or allotment, there are many benefits to growing them, especially for organic gardeners or anyone who wishes to reduce chemical use in the garden. When sown in autumn they prevent nutrients being washed away by winter rain and when dug in they return goodness back to the soil. Green manures are cheap, plus quick and easy to grow!


  • improve soil fertility and structure (improving drainage/water retention).
  • suppress weeds.
  • attract beneficial insects and other predators.
  • protect soil from being compacted by heavy winter rain.

At Mousehold Garden Centre we weigh up our green manures in paper bags on the premises, making them more economical for you to buy and reducing the need for plastic & excess packaging.

Grazing rye (Secale cereale): This annual crop is good for soil structure and overwinters well. Excellent to improve clay soils. Suitable for most soil types. Sow August to November and dig in the following spring. (Releases substances into the soil which prevent seed germination – excellent to stop weeds, but make sure you wait 4 weeks before sowing veg seeds).


1kg – £4.40 (53m²)

500g – £2.60 (26m²)

250g – £1.80 (13m²)

100g – 95p (5m²)

Mustard (Sinapis alba): This annual crop from the brassica family should not be followed by other brassicas, as it could encourage build up of the disease clubroot. Sow from March to September. Growing period 1-2 months. Requires a more fertile soil than grazing rye and phacelia and best in soils that don’t dry out too much. An excellent weed-suppressant – apply at a rate of 5g/m² if this is the primary purpose.


200g – £1.99 (100m²)

100g – £1.20 (50m²)

50g – 80p (25m²)

Phacelia (Phacelia tanacetifolia): Suitable for most soils. Stunning in full flower – it’s beloved by bees, butterflies and hoverflies! Sow March to September. Growing period 1-3 months. A good weed-suppressant – apply at a rate of 2g/m² if this is the primary purpose.


100g – £3 (100m²)

50g – £1.80 (50m²)

20g – 80p (20m²)

Sowing and digging in

Sow seeds in rows, or broadcast them across the soil and rake into the surface. When ready (before they become too woody or set seed) or once the land is needed for cropping, chop the foliage down and leave it to wilt. Dig the plants and foliage into the top 25cm (10in) of soil. After digging in, the site should be left for two weeks or more before sowing or planting out as decaying green materials can hamper plant growth. Alternatively, plants can be left to catch the frost (tender varieties such as mustard and phacelia) or covered with a light-excluding mulch. Mustard can also be hoed off when young.

RHS video guide for growing green manures

Organic gardening guide to green manures

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