You can also seed the green manure in the fall and then turn it under with a plow or a large tiller in the early spring. That way, you can use your garden normally while at the same time building up the soil.
Annual ryegrass is a good example for green manuring and covering. THIs should be seeded 1 to 2 feet per 1,000 square feet. If this is not available, you can use seed rye or wheat and place it 3 to 4 feet per 1,000 square feet. This helps prevent weeds from growing and in order for this to be effective, wait at least 2 weeks before you start planting.
Sewage sludge is also a good source of organic matter. There are two types namely digested sludge and dried activated sludge.
The first is relatively low quality. It contains from 1 to 3 percent of nitrogen and should only be applied during the fall. But you should be careful when you use it because it sometimes contain metal ions that are not good to use on vegetable gardens.
The second which is the dried activated sludge has been separated from coarse solids, inoculated with microorganisms and aerated. This is better than the other one because it is filtered, dried in kilns and screened. It contains 5 to 6 percent of nitrogen and 5 to 7 pounds can cover an area of 100 square feet.
Take note that these two types are different from raw sewage. That being said, never use that to garden any soil.
Sustainable organic vegetable gardening can only happen with organic matter. Now that you know this, choose from manure, compost or sludge.