UC Davis defines “organic” as referring to a living organism or materials derived from living organisms. Organic nutrients are nutrients that are naturally available from plant and animal sources. Organic agriculture promotes the use of renewable nutrient resources for plants, rather than chemical sources such as synthetic fertilizer. Soil that is rich in organic matter such as compost, is also rich in organic nutrients. Soil nutrients create food nutrients, so soil health is important. There are several organic nutrients that are essential for good plant growth.
Nitrogen is the organic nutrient needed in the largest amounts for healthy plant growth. It is present in soil microbes, which are the tiny living organisms in soil that come from decaying organic materials. Some plants, such as beans, are able to absorb nitrogen from the air and store it in their root system. Nitrogen helps plants grow rapidly and increases the development of seeds, vegetables and fruit. Nitrogen is readily available in large amounts from organic materials such as compost, blood meal, bat guano and fish meal.
Phosphorus is an essential nutrient that also helps transfer energy from sunlight to cell formation. It is involved in the formation of all sugars, starches and oils within growing plants. Phosphorus is important to encourage strong blooming and root growth. It is available in soil as decayed organic matter and from sources such as fish meal and bone meal. Phosphorus is part of the important nutrient cycle created by incorporating compost into the soil.
Potassium is the organic nutrient that is absorbed by plants in the largest amounts, except nitrogen. Potassium improves overall plant vigor and disease resistance. Potassium also supports good fruit quality and helps plants withstand compacted, clay-like soil. Plant cells use it to convert sunlight into growth nutrients. It is supplied to plant root systems by minerals in the soil that are present in decayed organic matter.
Calcium is an organic nutrient that plants need to stimulate root growth. It promotes firm, thick stems and helps correct soil acidity. Plants need calcium to absorb the nitrogen that is more essential than any other nutrient. Plant cell reproduction and cell wall strength are dependent on good calcium content in soil. Calcium is naturally available in bone meal, fish meal and all-purpose compost.