Essential plant nutrients are those nutrients that a plant needs to grow properly. Without these nutrients, a plant may die, may have stunted or no growth, or may have less of a yield than normal. Essential plant nutrients may be divided into two groups: mineral nutrients and non-mineral nutrients. Non-mineral nutrients are those that are not found in the soil. Mineral nutrients, which are are those found in the soil, can be augmented by fertilizers.
There are 16 essential plant nutrients that are needed for a plant to grow properly. Three of these are available to the plant through the air and water. These three nutrients are carbon, hydrogen, and oxygen. A plant uses these elements to undergo photosynthesis, a process in which air, water, and sunlight combine to make the sugars a plant needs to survive. Carbon and oxygen can be derived from carbon dioxide, and hydrogen and oxygen can be derived from water.
Apart from the three non-mineral essential plant nutrients, a plant also needs 13 mineral nutrients usually found in the soil. These 13 nutrients are commonly divided into two groups: micronutrients and macronutrients. Micronutrients are needed in small amounts by the plant, and macronutrients are needed in larger quantities. Both micro and macronutrients are essential for plant growth.
There are seven micronutrients that plants need: boron, chlorine, copper, iron, manganese, molybdenum, and zinc. These elements help the plant with photosynthesis, promote proper metabolism, and help the plant grow properly. In addition, some of these essential plant nutrients increase the taste of fruit and help seeds to form. Many times, micronutrients don't play an obvious role in the plant's growth. Some deficiencies may only be noted when the plant exhibits certain signs including a lesser yield, the yellowing of the leaves — sometimes in certain patterns — or stunted growth.
Macronutrients are those essential plant nutrients that are needed in a large amount by a plant. This group of mineral nutrients can further be divided into two subgroups: primary nutrients and secondary nutrients, depending on how much the plant uses. The primary nutrients — nitrogen, phosphorus, and potassium — are often used in such high quantities that the soil can become deficient of them. The secondary macronutrients are calcium, magnesium, and sulfur. These nutrients are often used in lower quantities than the primary nutrients, and so soil is not usually deficient of them.
Should the soil be lacking this or any of the other essential nutrients, it can be supplemented by many substances including fertilizers, compost, and yard waste. Many fertilizers available in stores will often have three numbers printed on them that correspond to the amount of nitrogen, phosphorus, and potassium it contains. The first number will always refer to nitrogen, the second to phosphorus, and the third to potassium. It is important to research new plants to discover the proper levels of these nutrients required by that plant.
Using yard waste and dead plant material can also provide growing plants with the nutrients they need, unless the clippings are nutrient deficient themselves. When using yard waste, one also has to be careful that there are no pathogens on the dead plant material that could attack the living plants.