In addition to sunlight, water, carbon dioxide, and oxygen, plants require certain elemental nutrients to survive and grow. Macronutrients are needed in relatively large amounts. These essential plant nutrients needed by plants are nitrogen, phosphorus, and potassium (the NPK on fertilizer labels), and calcium, magnesium, and sulfur. Micronutrients are no less important, but are needed in smaller amounts and are rarely deficient in most soils. The essential micronutrients are iron, manganese, molybdenum, boron, zinc, copper, chlorine, and nickel. Read on to learn more about how to fix nutrient deficiencies in plants.
Mineral nutrients in the soil get dissolved in water and then taken up through the plant’s roots into the plant tissue and cell wall. For this to happen, both the pH and the temperature of the soil must be within a specific range for each kind of plant. For example, even if iron is abundant in the soil, some plants (such as gardenias, azaleas, and blueberries) are unable to absorb it if the pH is too high. Cold temperatures also can inhibit the uptake of nutrients, as can waterlogged soils and (of course) soils that are too dry.
The nutrients most commonly deficient in plants are phosphorus, nitrogen, and iron. Phosphorus can be present in the soil, but in quantities too small to be taken up effectively. Nitrogen might be present, but in a form that cannot be used by plants. In alkaline soils, some plants are unable to take up iron.
If your plants are not growing like you think they should, they could be suffering from a nutrient deficiency. Have your soil tested to analyze the nutrient deficiency symptoms in plants. Fertilize regularly with formulas that contain the minor elements as well as the big three. This should prevent any nutrient deficiencies. Severe cases of nutrient deficiency can be treated with products specifically formulated for the nutrient in short supply. Keep healthy plants by amending the deficiency and continuing the life cycle!
Effects of Nutrient Deficiencies in Plants and How to Fix Them:
If older leaves (near the bottom of the plant) are chlorotic (yellowish), smaller, and drop earlier than normal, suspect a nitrogen deficiency. There also may be a pinkish flush to the leaves, and overall stunted, slower growth. Symptoms are most prevalent in early spring. Prevent nitrogen deficiency by regular mulching with organic matter. Cure the deficiency in the short term by applying a high nitrogen fertilizer such as manure, blood meal, ammonium nitrate, or urea.
If older leaves are purplish on the undersides but still dark green above, smaller than normal, and drop early, it could be a phosphorus deficiency. Leaf tips may die or look like they have been burned. Phosphorus deficiency is relatively uncommon, but may occur in areas with high rainfall and heavy clay soil, and especially in young plants during early spring when soils are still cold. Greensand and fertilizers with bone meal or superphosphate are used to remedy phosphate-poor soils.
If older leaves are wilting and have yellowing on the margins and/or between the veins, it could be a deficiency in potassium. Other symptoms of potassium deficiency include crinkling of the leaves, browning at the margins, and new shoots that die back prematurely. Plants will also show slower growth and reduced flowering and fruiting. Potassium shortages typically occur on light, sandy soils. Use a high potassium fertilizer such as muriate of potash, or a balanced fertilizer with a high K value to fix deficient soils.
A calcium deficiency can cause new leaves (near the top of the plant) to be abnormally dark green, distorted, or irregularly shaped. Eventually, the leaf tips turn brown and brittle and the leaves wither and drop. New shoots tend to wither on the tips. Calcium deficiency causes blossom-end rot in certain fruits, especially tomatoes. Soil deficiencies are rare, but irregular watering can inhibit the uptake of calcium. Prevent calcium deficiency with regular watering, and treat affected plants with products containing gypsum or calcium. Crushed eggshells are a great solution too!
Iron deficiency is indicated by young leaves that have dark green veins but are lighter pale green than normal between the veins. The distinction is sharp. Acid loving plants will show browning on the leaf margins. Eventually, the whole leaf becomes pale yellow and dies. Iron is typically inadequate supply in most soils but some plants cannot take up enough if the soil pH is above 6.5. The best remedy is to increase the soil acidity by applying chelated iron or manganese sulfate to the soil. Use a foliar spray for immediate treatment, and organic non-alkaline compost to maintain healthy soil.
If a plant has a magnesium deficiency, older leaves will appear thin and brittle and become yellowish on the margins and between the veins while the midrib remains green color. The result is a green “arrowhead” on a yellowish leaf. The difference between the green arrowhead and yellowish region between the veins is gradual, not distinct as it is with iron deficiency. Eventually, the leaves will wither and drop, even as shoot growth appears normal. Light, sandy soils are sometimes deficient in magnesium. To improve magnesium availability in the soil, apply dolomitic limestone or Epson salts(magnesium sulfate) as directed. For a short term fix, spray leaves with a nutrient solution of Epson salts.
Sulfur deficiency can resemble nitrogen deficiency, but the symptoms (pale, light green leaves) show up in the younger, lower leaves first. Older leaves tend to be smaller and lighter green than normal, and shoots are often shorter and thinner than normal. Treat sulfur deficient soils with products containing sulfate.
If younger leaves exhibit chlorosis between the veins and older leaves are paler green than normal and have darker green bands parallel to the veins, a manganese deficiency is indicated. Leaves will eventually wilt as though water-stressed, and plant growth will be slower than normal. Treat manganese deficiency with manganese sulfate.
Molybdenum deficiency can occur in cole crops (Brassicas) grown on acidic soils. Symptoms can be similar to nitrogen deficiency, with poor growth and chlorosis on lower leaves. Look also for elongated, twisted leaves that can be rolled or cupped. Apply a fertilizer containing the micro-nutrient trace elements and if the soil is acidic, lime it before planting.
Stunted growth, dieback of the terminal bud, and brown cracks on stems and fruits can be a sign of a boron deficiency. Also, if there is not enough boron in the soil, leaves may develop brown irregular spots and become brittle and curled, and witches’ brooms may form. Boron is rarely in short supply but can be unavailable to some plants on alkaline soils. Apply borax (disodium tetraborate) to the soil before planting or as a foliar spray when symptoms are observed. Reduce soil pH with magnesium sulfate.
Plants deficient in zinc will exhibit chlorosis between the leaf veins, appearing as yellowish or whitish stripes between the midrib and margin. Leaves also can be stunted and misshapen. Yellowing between the leaf veins is the first sign. Treat zinc deficiency with fertilizers containing zinc or its organiuc compounds.
Plants with a copper deficiency show yellowing in young leaves, and slow growth. Eventually, the leaves turn brownish. Treat deficient soils with products containing copper.
Symptoms of chlorine deficiency can include yellowish leaves that have rounded dead spots that are sharply delineated from the rest of the leaf. Roots may exhibit excessive branching, and leaves may be wilted along the margins. Chlorine deficiencies rarely occur. If necessary, chlorine can be provided in the form of calcium chloride, potassium chloride, ammonium chloride, or magnesium chloride.
Nickel is rarely deficient in soils, usually not assayed in soil tests, and generally not included in commercial fertilizers. Nickel deficiencies are not well understood but can include poor seed germination, leaf chlorosis, and stunted growth. If soil remediation is called for, nickel sulfate or a chelated form of nickel can be used.
If you think your plants are deficient in one or more of the essential nutrients, have the soil tested. If there is a shortage, ask your county agricultural extension agent about remedies used in your area. Plant health is essential to keep a long life expectancy. Specific nutrient deficiencies in plants don’t have to affect your garden if you take action early!
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