Green Manures
Green manures are plants that are sown on vacant ground to protect and improve the ground, usually over winter but not necessarily so.
Grasses, mustard, vetches and clovers are the most common and the Tuckers catalogue lists them with characteristics and sowing periods.
Grasses, mustard, vetches and clovers are the most common and the Tuckers catalogue lists them with characteristics and sowing periods.
After sowing the seed the crop grows and then, before it has time to seed, is cut down and left to wither for a week or two (- or composted if you are in a hurry!) then dug in.
The top growth protects the surface from compaction, while the roots trap water and nutrients and maintain the structure of the soil. The plant material helps to improve the humus content of the soil when dug in.
All the green manures are annual and so selected not to cause problems once dug in. However, there are a couple of points of caution.
The top growth protects the surface from compaction, while the roots trap water and nutrients and maintain the structure of the soil. The plant material helps to improve the humus content of the soil when dug in.
All the green manures are annual and so selected not to cause problems once dug in. However, there are a couple of points of caution.
- The rotting material exudes a substance that tends to stop seed germination, so direct sowing straight after digging in (e.g. carrots or turnips) may result in poor germination.
- Mustard is in the brassica family and so, while one of the easiest manures to use, should be avoided when clubroot is a problem.
My experience of using grazing ryegrass was very good. The grass grew well, so well I had to cut and compost it 4 times in the Spring as I was so slow to dig the patch over, and the soil was full of tiny hair roots that held the normally loose sandy soil together. The top growth was buried and provided a moisture store as it rotted.
Vetches (sown in with grazing rye) were less successful as few seeds germinated - though the nitrogen fixing properties were probably good as there were copious nodules on the roots of the few plants there were.
Beans (surplus seed saved from the previous years crops) also did not germinate well but also offered nitrogen fixing.
Vetches (sown in with grazing rye) were less successful as few seeds germinated - though the nitrogen fixing properties were probably good as there were copious nodules on the roots of the few plants there were.
Beans (surplus seed saved from the previous years crops) also did not germinate well but also offered nitrogen fixing.
