Magnesium Roles in Plant Health

April 24, 2023

High brix content is so important from a plant health and energy perspective. If we are foliar feeding or running nutrients through the drip, we should constantly be evaluating if what we are doing is making a difference in brix content. Today, I would like to discuss a few impacts that magnesium has on brix content.

Plants need to be dark green in order to have the highest brix content possible. We know that solar panels are much more efficient now than they were ten years ago. Similarly, our plants can become much more efficient at harvesting sunlight when they are dark green. We all know that nitrogen turns plants dark green, right? But do we give enough credit to magnesium and iron, which also have a tremendous impact?

The chlorophyll molecule is 4 atoms of nitrogen, with magnesium in the center. This means that nitrogen alone cannot give us true chlorophyll; it also takes magnesium. How often do we balance out all the nitrogen that is applied with some magnesium?

Magnesium has some other interesting roles as well. For example, according to the “Plant Analysis Handbook”, magnesium activates more enzymes in the plant than any other mineral. It activates a total of about 300 different enzymes.

Magnesium promotes better phosphorus availability. Both phosphorus and magnesium are critical in activating enzymes that are involved in ATP, which is basically production of energy. When plants have higher levels of ATP, they have much more energy and will grow faster, stronger, and healthier. Plants need lots of energy to get other nutrients into the new growth. I am specifically thinking here about calcium, but the same may be true of other minerals.

Magnesium is also very involved in protein synthesis. In other words, magnesium helps convert soluble forms of nitrogen, such as nitrate or ammonium, into amino acids and proteins, which contributes significantly to natural insect and disease resistance.

One grower experienced the difference accidentally. He mixed his foliar applications and started spraying, then when he was about 30’ into the field, he remembered that he had not added any PhotoMag to the tank. So he stopped, grabbed some PhotoMag, added it to the tank, then sprayed the rest of the field. The amazing part was that several days later he noticed significantly more insect pressure in those first 30’ where he had not sprayed the PhotoMag.

The visual deficiency of magnesium is old leaves that are yellow with veins that are still green. Growers have reported seeing visual differences in leaf color and leaf expression after foliar feeding epsom salt or PhotoMag, sometimes overnight. In the case of leaf expression, it is common for magnesium deficiency to show up as twisted, brittle leaves that appear almost drought stressed.

Another interesting point: don’t think you are exempt from this if you have excessive magnesium in your soil. Research has proven that soils with excessive magnesium are almost guaranteed to be magnesium deficient.

In summary, is it under-used in your case? Maybe you need to experiment. Do a brix test before and after.