Magnesium Deficiency: How to Diagnose and Treat

Before we investigate the symptoms of a magnesium deficiency, we must first discuss the importance of magnesium within your plant.
Magnesium is absolutely essential and is a secondary macronutrient that your plant uses for growth and health. It plays a vital role in the process of photosynthesis, the process that your plant uses to take in light. It is the key element within chlorophyll, the thing in plant leaves that makes them green!

As it is used as an activator within your plant for multiple enzymes, a deficiency of magnesium will lead to a definite decrease in enzyme activity meaning that your plant will experience stunted growth. Not only will it affect the growth of your plant, it will affect its ability to:


  • Uptake nutrients correctly
  • Oil and fat formation
  • The use of iron
  • Transportation of sugars.

Identifying Magnesium Deficiency.
Ideally, your plant needs to be resolved of a magnesium deficiency immediately, but to do that you must be able to detect the factors of deficiency.
One of the initial stages of Magnesium deficiency is a condition called Chlorosis, which is the yellowing of the leaf between the veins and around the edges. If older leaves are turning yellow at the edges and staying green in the centre whilst all other growth remains unaffected, this shows magnesium deficiency.
Another, less commonly known sign of magnesium deficiency is purple stems on fan leaves and main stem areas.

If you leave a magnesium deficiency unattended, you could experience:

  • Dropping of older leaves
  • Slow or completely halted growth
  • Leaf necrosis (death of plant cells and tissues)

Causes of Magnesium Deficiency and Treatment.
Growth Medium- Your choice of growth media can affect how your plant absorbs nutrients. For example plants grown in coco coir often experience deficiencies with magnesium, calcium and iron as coco holds onto nutrients well, making them unavailable to your hungry plant. If your medium is the cause, be sure to add CalMag to your nutrient solution, but follow the instructions on the bottle as adding too much can cause a nutrient lockout, where your plant will uptake nothing!

pH Levels- Make sure the pH levels of your plant’s nutrients and media never goes above 6.0 and never goes below 5.5. If the pH moves outside of this range it will affect your plant’s ability to uptake nutrients correctly. Within the range your plant will not struggle to uptake anything. pH is important and if you want to avoid pH issues completely, we recommend using a “pH perfect” nutrient line such as Sensi Grow & Sensi Bloom by Advanced Nutrients. Their line offers A+B grow and bloom nutrients for both soil and coco!

Author: Hydroponify

We know all things hydroponics.

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