Green manure - something to experiment about!

We’re green about green manure, but we’re experimenting and learning. It has been something we have often discussed while weeding and this Autumn we have decided to see what grows well and what we like.

There are advantages and disadvantages to growing green manure and so it is not just a simple process. Is it better than adding compost as a mulch? 

Advantages of green manures:

· Some fix nitrogen.
· They reduce leaching of nutrients.
· Some deep-rooted ones bring nitrogen and nutrients up from deeper and when chopped and incorporated into the soil these are released.
· They reduce weed growth.
· They reduce wind erosion.
· They can help break up heavy clay.
· They provide habitat.

But there are disadvantages, too:

· They may provide a good habitat for slugs and snails to breed in.

· You need to wait for about 4 weeks after cutting and incorporating the green manure before sowing another crop.

· Some are brassicas so you need to plan your crop rotation not to have cabbages and other plants in the family growing immediately after a brassica green manure.

· You can’t pile on lots of compost and high organic matter materials over the slower winter period.

This September we sowed several types of green manure to see how they fare in our soil and how we get on with them - phacelia, red clover, white clover, mustard and marrowfat peas. The last two are from organic food shops and so much cheaper than buying a packet of seeds. The mustard may not survive a cold winter. The marrowfat peas are really cheap - ours have kept for years and still have a great germination rate.

We still have beds that we will cover with a mixture of compost and well-rotted woodchips. Our soil is sandy loam so we are lucky but we are always trying to increase the levels of organic matter.

The article features a few pictures of our beds, covered in green manure seedlings - photos taken in a rainy October.