Magnesium – Plant Nutrition’s Step Child?

Magnesium – Plant Nutrition’s Step Child?

Not all plant problems are caused by disease and insects. Nutrient deficiencies in plants result in reduced growth, reduced yield, lower quality and aesthetics, reduced flowering and fruiting. Fertilizers correct nutrient deficiencies in plants. Following is a perhaps “dry” discussion about Magnesium and its’ role in plant growth yield and success. Often it is the little things in the background that seldom get noticed or recognized in life yet do the “Heavy Lifting” and are essential to success. In the life of a plant, Magnesium deserves more recognition.

Magnesium (Mg) is considered a secondary element required for plant growth. The term “Secondary” describes relative nutrient quantity but not importance. As we know from “Liebig’s Law” (previous posts), a “Secondary” nutrient deficiency is just as destructive to plant growth, quality and yield as one of the three primary nutrients (N, P, K). Yet Magnesium is often overlooked and adversely affecting both quality and yield of ornamental and agronomic species.
Magnesium is the eighth most abundant element in the earth’s crust, and the fourth most abundant metal ion in cells. It is present in every cell type in every organism. Magnesium is essential to the well being of all organisms. So much for “Secondary”, right? It is the central atom in the chlorophyll molecule. Chlorophyll is a pigment that makes plants green and creates photosynthesis. Magnesium roles in the plant include:
• The coordinating ion in the chlorophyll molecule, thus making photosynthesis possible.
• ATP (adenosine triphosphate) is the primary energy source in cells. ATP to be active and available must be bound to a Magnesium ion.
• Magnesium regulates uptake of other materials in the plant. It acts as a carrier of Phosphorous to seeds. Magnesium aids in production of proteins, fats and vitamins. Magnesium plays a role in starch translocation or movement within the plant.

Many factors affect Magnesium availability, and we should be aware of these variables. They include:

• Soil Magnesium content – how much is already in the soil?
• pH – Magnesium is more available at higher pH’s or less acid soils.
• Other factors include Manganese/Magnesium ratio, Cation Exchange Capacity (CEC), Potassium (K) and Calcium (Ca) and cation competition, cool soil temperatures.

Plants differ by species and variety in Magnesium needs. High response food crops include: blueberry, beet, broccoli, cabbage, cauliflower, celery, corn, cucumber, eggplant, lettuce, onion, spinach, squash, tomato and watermelon.

Magnesium is a mobile nutrient taken up by the roots. The first observable sign is a depressed rate of photosynthesis or growth. Next is carbohydrate immobility. This is where sugars are produced in the leaves but cannot be transported throughout the plant. Sufficient Magnesium levels are required to maximize carbohydrate transport to “Sink” organs in the plant like seeds, roots and fruit. This promotes higher yields and growth. Due to the lack of mobility, visual symptoms of interveinal chlorosis (yellow leaves with green veins) occur in the older, lower leaves first. In citrus, this symptom is referred to as “Bronzing.”

Soil testing is the best method to measure nutrient availability, determine crop needs and receive specific recommendations. Dolomitic Limestone is most commonly used to correct both Magnesium deficiency and acidity or pH levels. Other materials to correct Magnesium deficiency include:

• Potassium Magnesium Sulfate (Sul-Po- Mag)
• Magnesium Nitrate
• Magnesium Sulfate (Epsom Salts)
• Chelates – These are well suited for foliar application and often plants will respond more quickly.

Talking to growers, farmers, nurserymen and garden center managers about nutrient management and plant nutrition I have noticed that the importance of Magnesium is often misunderstood. And here’s the thing – it is critical to all life, well being, health and appearance. Be it photosynthesis (not “Secondary” in anyone’s book), protein synthesis, carbohydrate transport to vital areas in the plant, and ATP or energy production within the plant cell. And plant species have different nutritional needs. All Plants require certain “Essential” nutrients in adequate, balanced and available amounts. BGI products are about providing these nutritional goals. Our products are designed to provide proper nutrition, so the plant and the grower can experience growth, beauty, yield and satisfaction. Let BGI help your plants reach their potential and allow you, or your customer to harvest satisfaction and joy in the process!

Take care,


P.S. It’s pretty cool I think that many of the human “Super Foods” just happen to be high in our stepchild, Magnesium like spinach (dark leafy greens!), almonds, avocados and dark chocolate! Maybe there is a message here…..? I think so.