Your garden is not growing as well as it use to and some of the plants in the garden are starting to look a little yellow. You suspect a nitrogen deficiency in the soil, but you are unsure how to correct it. "Why do plants need nitrogen anyway?" you may be wondering.
Nitrogen as a plant fertilizer is essential to proper plant growth. Without nitrogen, a plant cannot makes the proteins, amino acids and even its very DNA. This is why when there is a nitrogen deficiency in the soil, plants are stunted. They simply cannot make their own cells. In order for plants to use the nitrogen in the air, it must be converted in some way to nitrogen in the soil. This can happen through nitrogen fixation, or nitrogen can be "recycled" by composting plants and manure.
Organically Fixing a Nitrogen Deficiency in the Soil:
To correct a nitrogen deficiency using organic methods requires time, but will result in a more even distribution of the added nitrogen over time. Some organic methods of adding nitrogen to the soil include:
• Adding composted manure to the soil
• Planting a green manure crop
Green manure is a term used to describe specific plant or crop varieties that are grown and turned into the soil to improve its overall quality. A green manure crop can be cut and then plowed into the soil or simply left in the ground for an extended period prior to tilling garden areas. Examples of green manure crops include grass mixtures and legume plants. Some of the most commonly used are:
⁃ Annual ryegrass
⁃ Mulch with leaves
• Adding coffee grounds to the soil - Coffee grounds are about 2 percent nitrogen by volume, making them an excellent addition togarden soil.
• Grass clippings are a free and easy way to add nitrogen and potassium to the soil.
Source : Various internet sites & books