Why Do Plants Need Nutrients?
Like animals, plants need nutrients to live. If seeds don’t have access to nutrients, they will not germinate. And if the nutrient supply runs out later in the plant’s life cycle, it will start to atrophy and eventually die. OK, but why do plants need nutrients? What nutrients are we talking about? And what exactly are they doing?
What Nutrients Do Plants Need?
Nutrients are chemical elements or compounds that living organisms use to support vital life processes and functions. For instance, plants need nutrients to make the photosynthesising chemical chlorophyll and activate the enzymes necessary to catalyze reactions that fight diseases and pests, produce flowers, and grow stems, roots and branches.
The specific nutritional needs of plants vary from species to species, but there are around sixteen nutrients that are essential to survival. Thirteen of these are sourced from soil matter or fertilizer. They are nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, zinc, manganese, copper, boron, molybdenum, and chlorine. The other three – carbon, hydrogen and oxygen – are taken from the air or water.
Nutrients that plants need in the largest quantities are called macronutrients, while those that are only required in smaller amounts are known as micronutrients, or trace minerals. The nine macronutrients are nitrogen, phosphorus, potassium, calcium, sulphur, magnesium, carbon, oxygen, and hydrogen. The seven micronutrients are iron, zinc, manganese, copper, boron, molybdenum, and chlorine.
Why Do Plants Need Nutrients At Different Quantities?
Macronutrients are also required by plants at different quantities to one another. Other than oxygen, hydrogen, and carbon, the macronutrients plants need in the largest quantities are nitrogen, phosphorous, and potassium. Unlike micronutrients, plants often cannot find enough of these nutrients in the soil to meet their needs. This means gardeners must add fertilizer to the soil containing some combination of nitrogen (N), potassium (P), and phosphorous (K). This is what’s known as the NPK ratio, or NPK value.
Why do plants need nutrients NPK at a specific ratio?
This is partly because a plant's specific nutritional requirements change throughout its life cycle, but also because it’s not just nutrient deficiencies that can be harmful to plants. Too much of any nutrient can also cause problems.
Why Do Plants Need Nutrients for Specific Types of Growth
The answer to the question, why do plants need nutrients for specific types of growth is not known. What is know, however, is that specific nutrients contribute to different types of growth in plants.
Nitrogen promotes healthy foliage growth and assists with chlorophyll production, so it’s important in the early stages of a plant’s growth. However, too much nitrogen once the plant has already grown strong stalks and luscious leaves can inhibit flowering and weaken immunity.
Phosphorous is necessary for seed germination, root growth, and flowering, so it’s required in large amounts during the early and later phases of a plant’s growth cycle. Too much though can prevent the absorption of important micronutrients, like iron and zinc.
Potassium, meanwhile, provides strength to the plant and helps protect it against disease and pests but an overabundance can also inhibit the absorption of nutrients, in this case magnesium and calcium.
Getting the NPK ratio right for your plants is therefore crucial, and it depends not only on what plants you want to grow but also on the soil conditions in which you will grow them. The same is true for other macro and micronutrients as well. It’s not just about what your plants need, but when they need them too!
If you’re still wondering why do plants need nutrients, check out BAC’s Knowledge Centre for more information. Alternatively, explore our range of soil nutrients designed to help bring out the bloom in your garden!