Green Mulch-Lupins

Another great way to "fix" poor soils is a Green crop which are normally grown over the Autumn-Winter months. When the crop flowers they are cut down and dug in to provide organic matter to improve the structure of the soil, generally speaking you can plant back in the soil a month later.
Lupins:
 This crop fixes mainly Nitrogen but also small amounts of Phosphorus into the soil via the roots during its growing cycle. The root system is quite fibrous which contributes a lot of organic matter along with the top of the plant. Sow the seed in the Autumn and when it flowers cut it down and dig in, clay soils will open up however sandy soils benefit greatly from this plant, my father in law an avid gardener on the coast swore by lupins to add substance to his light soils.
Be Happy
Barry