There is more to fertilizers than just N, P and K. There are 12 essential nutrients need to stay healthy. The absence of even one of these can put your plants in a tail spin. Let’s discuss these nutrients and what effects they will have when deficient in plants.
Macronutrients are nutrients needed in large supply. These are the nutrients that are most important to plants. We will start with the 6 macronutrients and then discuss the 6 Micronutrients. Micronutrients are needed in smaller quantities but still critical for plant life.
Nitrogen is part of all living cells, necessary for proteins, enzymes and a key player in the transfer of energy in photosynthesis. Nitrogen comes in different names like urea, nitrate or ammonium. Flushes out green growth and gives chlorophyll in plants that green color.
When deficient, plants will turn yellow and tend to grow slower than usual.
Phosphorus is also part of photosynthesis. It helps make oils, sugars and starches. Phosphorus also helps with root establishment which helps transport nutrients and energy throughout the plant. It is often found in starter fertilizers, bone meal, bloom boosters and root stimulators.
When deficient, seeds struggle to survive, new plants can struggle to establish and blooming plants will not produce blooms. Leaf tips will look burnt and older leaves can turn reddish purple.
Potassium helps build protein, aids in photosynthesis and helps prevent disease and increase winter hardiness. K is often supplied by organic matter and heavier in fall/winter fertilizers. K is also called Potash. Typically winterizer fertilizers will have elevated potassium.
When deficient, older leaves may wilt or look scorched. Plant can get interveinal chlorosis, where leaves turn yellow but veination stays green.
Calcium helps to retain and transport other nutrients by providing strength and structure through its cell walls. It comes as pelletized or powder lime, gypsum or liquid form for blossom end rot. Helps in conjunction with magnesium in bringing soil pH up.
When deficient, new leaves curl and become irregularly shaped. Also causes blossom end rot in crops like tomatoes.
Helps activate plants enzymes and part of chlorophyll and photosynthesis. Magnesium works in conjunction with calcium and as a charged ion, will leach out of the soil quickly if calcium is not present. Found in lime and Epsom salt.
When deficient, the edge of older leaves turn yellow, leaving green arrow shape inside the leaf.
Sulfur is essential for the production of protein and chlorophyll. Sulfur acidifies soil and works opposite of lime (calcium and magnesium) in regards to soil pH. Sulfur also helps with root growth, seed production and cold resistance. Sulfur is common in rain water and used in lower quality fertilizers often listed as ammonium sulfate.
Sulfur deficiency often appears as yellow new growth that then can move to older leaves.
Iron is essential for chlorophyll production which is essential for photosynthesis. Iron is absorbed as an ion through roots and leaves and is very dependent on proper soil pH for absorption into the plant.
Yellowing of the leaves between leaf veins is common. Make sure soil pH is at proper levels before assuming iron deficiency.
Manganese is an ion, absorbed through roots and leaves. Manganese helps break down carbohydrates and helps metabolize nitrogen.
Its deficiency is more abundant when there are iron and zinc deficiencies. Deficiency causes a chlorosis in the leaves interveinal tissue. Plant parts can have stunted or deformed growth as well.
Zinc is important in driving metabolic reactions in plants and crops.
Broad white stripes on leaves will appear on leaf midrib when there is an absence of zinc and most commonly deficient in crops.
Boron helps in the production of sugar and carbohydrates and is essential in seed and fruit development.
Boron becomes most deficient in sandy soils with little organic matter. Deficiency is most prominent in spring with absence of rain. When boron is absent, terminal buds will die and witches brooms forms. Deficiencies in Brussels sprouts will commonly form hollow stems due to the increased amount of Boron required by this plant.
Copper works with beneficial enzymes that regulate chemical reactions in plants. Most deficient in organic or peat based soils. Copper promotes the production and formation of seeds as well.
Deficiencies mostly appear in wheat fields and some other small grains. It presents light green to yellow grain crop.
Molybdenum helps assist beneficial enzymes that are responsible for metabolizing nitrate.
Silvery leaves are possibly when deficient or reddish purple leaf veination.
Specialty fertilizers like Vigoro Tomato Vegetable Food are designed specifically for your crops, including micronutrients like calcium to prevent Blossom End Rot that is so common. Vigoro Azalea Food is another one that includes the micronutrient sulfur to acidify soil for acid loving plants. I highly suggest specialty fertilizers for any crop plot where anything is being harvested, as they have almost all of these micronutrients and will help prevent problems down the road.
Soil pH is the key player for a plant. When soil pH is not right for the particular plant, nutrient absorption becomes the issue. When a plant does not really react to fertilizer, this is a sign that its pH is off. A large majority of the time, deficiencies will most likely be a macronutrient.
Certain types of soils are more notorious for certain deficiencies than others. Different soil types will leach nutrients out quicker than others. Sandy soils will leach nutrients because it can drain water quicker, taking these nutrients with it. Sand is also easy for roots to spread through to look for nutrients. Clay soils retain nutrients well, as it is less porous, making it more difficult for nutrients to escape. This being the case, roots have a hard time spreading through the hard clay unless it is amended. The ideal soil has a good balance of sand, silt, clay and organic matter. Visit your local horticulturalist at your nearest Home Depot store and they can tell you which deficiency is most likely in your area or send a soil sample to your county extension office for a soil test. Check out this article on Amending Different Soil Types.
Soil deficiencies are more prominent in heavily farmed land where nutrients are taken from crops. Crop rotation is recommended to fix that in conjunction with fertilization. Any time something is taken away, it can cause a deficiency. Same thing applies when you bag up your grass clippings from the lawn and dispose of them. Bag every other time or cut with more frequency to solve this problem.
Different plants are notorious for certain deficiencies and many deficiencies look the same. Gardenias for example, are notorious for yellow leaves. First thought should be a nitrogen deficiency but it is actually Iron that they need. In grass, that could be soil pH, Iron or Nitrogen.
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