Just like us, cannabis plants need nutrients to survive and thrive to their full potential. A plant lacking a specific nutrient cannot produce high yields and places the rest of the crop at risk. While there are multiple kinds of nutrients that cannabis plants need, there are a handful of primary ones.
Magnesium is one of these main nutrients. A deficiency in magnesium can lead to severe complications and health risks in a cannabis plant. Identifying deficiencies in cannabis crops is one of the building blocks towards becoming a skilled cultivator.
Magnesium is a natural element that living beings need to survive. It is one of the secondary nutrients that cannabis plants require, alongside calcium and sulfur. This nutrient is naturally occurring but must be added to a feeding schedule when cultivated in a controlled environment. For example, coco allows growers to have greater control over the nutrients their plants are consuming but requires nutrients like magnesium to be included in their feeding schedules.
We know that cannabis plants need magnesium, but what exactly does it give to a plant?
According to the University of Minnesota Extension, “Magnesium is the central core of the chlorophyll molecule in plant tissue. Thus, if Mg is deficient, the shortage of chlorophyll results in poor and stunted plant growth.”
Chlorophyll is the part of the plant that absorbs the light, which is then transferred into energy the plant can use. National Geographic states, “The plant uses the stored energy to convert carbon dioxide (absorbed from the air) and water into glucose, a type of sugar. Plants use glucose together with nutrients taken from the soil to make new leaves and other plant parts.”
Without the proper amount of magnesium, a cannabis plant will not have what it needs to remain healthy. Let’s take a closer look at what exactly will happen to a cannabis plant that has a magnesium deficiency.
If a cannabis plant does not get the magnesium it requires, the plant can suffer. This can cause many problems with the plant, no matter the stage in its lifecycle.
One of the things that can happen to a cannabis plant deficient in magnesium is something called Chlorosis. According to the Cannabis Business Times, “Chlorosis caused by a Mg deficiency will appear as a marginal yellowing of the lower leaves. The interveinal chlorosis at the leaf tips will spread into the leaf margins, and prolific interveinal chlorosis will develop on the lower foliage of the plant.”
A lack of magnesium and the resulting lack of chlorophyll will leave a plant susceptible to viruses, viroids, molds, and pests. Just like humans when our immune system is not working as it should, cannabis plants become weaker and more prone to illness. A plant with a weakened immune system will put the other plants around it at risk. However, this can be avoided if a grower knows what to look for when spotting a magnesium deficiency.
Will a cannabis plant tell its grower that it is lacking magnesium? In short, absolutely. But a grower has to know the signs to look for.
In older leaves, symptoms may appear as drying and curling, often dropping and creating an ideal environment for pests. Irregular rust-colored splotches may appear and leaves will turn yellowish in color. Overall, the plant will look sickly.
In many cases, magnesium deficiencies can be remedied by adjusting the nutrients fed to the plants. It is important to remember that different strains require different amounts of nutrients. What nutrient feeding schedule may work for one strain may not work for another.
Want to learn more about nutrients? Verne Bio’s Knowledge Center has a wide variety of information available for growers of all experience levels. Readers can learn everything from the viruses and viroids that impact cannabis crops to tips and tricks on how to help your cannabis plant grow to the best of its ability.
Readers can also sign up for our newsletter, where new content will be delivered right to their inbox. Learning about cannabis and the cultivation industry surrounding this incredible plant has never been easier. So what are you waiting for? Come check Verne Bio’s Knowledge Center!
Works Cited
Kaiser, Daniel E., and Carl J. Rosen. “Magnesium for crop production | UMN Extension.” University of Minnesota Extension, 2016, https://extension.umn.edu/micro-and-secondary-macronutrients/magnesium-crop-production. Accessed 26 September 2023.
Loud Clouds. “.” . – YouTube, 2 October 2022, https://loudclouds.co/wp-content/uploads/2016/07/marijuana-deficiency-chart-jorge-cervantes.jpg. Accessed 24 September 2023.
Peters, Kristian. “Chlorophyll.” National Geographic Education, 8 May 2023, https://education.nationalgeographic.org/resource/chlorophyll/. Accessed 27 September 2023.
Whipker, Brian. “What Are the Optimal Rates for Magnesium in Cannabis?” Cannabis Business Times –, 2021, https://www.cannabisbusinesstimes.com/article/research-optimal-rates-for-magnesium-in-cannabis-cultivation/. Accessed 24 September 2023.
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