When it comes to healthy plants and strong yields, micronutrients are just as important as macronutrients. Like your vitamins, plants only need these micronutrients in small amounts. But, not receiving these micronutrients can cause undesired results related to the specific deficiencies.
Plant micronutrients include: Boron, Copper, Iron, Manganese, Molybdenum, Zinc, Chlorine, and Nickel.
Why do micronutrient deficiencies occur?
Soil is almost never rich enough in all the macro and micronutrients a certain plant needs. A fertilizer should be used to supplement the soil. Fertilizers (especially non-organic) often market high NPK macronutrient levels, but do not provide a healthy balance of other macro or micronutrients. A good organic fertilizer replenishes the soil with a balanced NPK rating, other macronutrients, and micronutrients.
What are the micronutrient deficiencies?
Boron (B) - This important micronutrient affects membrane stability. Boron supports cell membranes' structural and functional integrity. Boron-deficiency symptoms first appear at the growing points of a plant, and manifest in wrinkled leaves. Boron helps seed set, and is especially important in drought conditions.
Copper (Cu) - Copper helps ensure successful protein synthesis. Plants with copper efficiency lose turgor in the leaves and develop a blue-ish green color before curling.
Iron (Fe) - Iron is essential for growth and food production. Iron helps energy transfer, nitrogen reduction and fixation, and lignin formation. An Iron deficiency will cause a pale green leaf color, and high contrast between green veins and yellow leaf tissue.
Manganese (Mn) - This activates important metabolic reactions and is crucial for photosynthesis. Manganese accelerates germination and maturity. It increases the availability of phosphorus (P) and calcium (Ca). A Manganese deficiency will also manifest in yellow leaf tissue between veins, and sometimes as brown-black specs.
Molybdenum (Mo) - Molybdenum deficiencies are relatively rare, but the micronutrient is crucial for enzyme synthesis and activity. The deficiency manifests as a yellowing and stunting of the plant.
Zinc (Zn) - Zinc was one of the first micronutrients recognized as essential for plants because it is the most common factor in limiting yields. Zinc is not needed in high amounts, but strong yields are impossible without it. Zinc deficiency appears first on the youngest leaves, causing stunted leaf growth, and hyper-dry spots or edges on leaves.
Chlorine (Cl) - Required by energy reactions in the plant. Most Chlorine comes from salts, marine winds, and volcanic soils. Chlorine regulates (minimizes) the water loss of plants. Without sufficient Chlorine, a plant cannot acclimate to water availability. A Chlorine deficiency manifests in yellow spotting on the leaves.
Nickel (Ni) - Nickel supports Nitrogen metabolism Without Nickel, urea conversion is impossible. Plants with insufficient Nickel grow small stunted leaves (mouse-ear condition).
What is the best way to ensure micronutrient supply to a plant?
Use a good organic fertilizer. Non-organic fertilizers often contain strong macronutrients, and market a high NPK rating, but the micronutrient content is insufficient or imbalanced.
Organic fertilizers can be weak, so it's important to select one that contains a broad balance of micronutrients. A feature of the best organic fertilizer will be strong amounts of Iron and Zinc.