Green manure
From Allotments4All
Introduction
Most green manures are sown in spring to be dug in during the autumn, or planted in the autumn to over winter. Also you need to keep in mind that after it has been dug in, the ground needs to be left for usually a minimum of a couple of weeks before planting. Of course, it depends how much later in the year you're thinking of growing your veg
This website is quite useful in sowing times: http://www.btinternet.com/~bury_rd/green.htm and scroll down to the table. It's helpful, but not extensive, there are many more green manures, have a google for it. They also do different things, and that site doesn't say which ones fix nitrogen.
Crops Used and Details
Alfalfa
, Alfalfa is quite a quick growing green manure
Buckwheat
Buckwheat can be grown towards the end of the summer
Mustard
Mustard is terrifcally fast, 2-8 weeks
