Cannabis Manganese Deficiency

How to Treat Cannabis Manganese Deficiency

One of the most important cannabis plant nutrients is manganese. It is a micronutrient that is the second greatest needed element next to iron. Lack of manganese can affect the growth of cannabis plants. Manganese deficiency is usually mistaken as iron toxicity or deficiency.

In this article, you will learn how to treat cannabis manganese deficiency to keep you guided accordingly and avoid this issue from occurring in your marijuana plants.

What Are the Causes of Manganese Deficiency?

If the pH level of the medium used in cultivating cannabis exceeds 6.5, manganese deficiency may occur. It is because an off pH level restricts nutrient reuptake or drawing of nutrients from the soil to your marijuana plants.

Take a look at the other causes of manganese deficiency:

  • Low fertilizer application rates
  • The use of general-purpose fertilizers have reduced micronutrients)
  • Excessive leaching
  • Applying excessive iron chelate drenches

What Is the Function of Manganese?

Manganese is a major contributor to complex biological systems of marijuana plants including the following:

  • Photosynthesis: It is the natural process of plants using the UV rays from the sun to be converted as an energy source which helps in the production of chlorophyll or the green pigments found in the plants.
  • Nitrogen Assimilation: This process refers to organic nitrogen compound formation, such as converting inorganic nitrogen compounds to amino acids. These inorganic nitrogen compounds are usually present in the environment.
  • Respiration: It refers to the oxygen uptake of plants or the utilization of oxygen by cannabis plants.
  • Pollen Germination: This process refers to the production of pollen required for reproduction or breeding of cannabis plants.
  • Other Functions of manganese: Root cell elongation, pollen tube growth, and root pathogen resistance.

What Is the Relationship Between Manganese and Iron?

Manganese is usually an overlooked element that is present in a soil medium. Manganese and iron have a symbiotic relationship, wherein if cannabis plants are lacking in manganese, they can be misdiagnosed as iron deficiency. Knowing what signs to look for can help you determine if your growing cannabis plants are showing signs of iron deficiency or manganese deficiency.

What Are the Signs of Manganese Deficiency?

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If your cannabis plants suffer from manganese deficiency, the signs usually appear like iron deficiency, which include the following:

  • Interveinal chlorosis or yellow cannabis young leaves with green veins
  • Sunken spots appear in the discolored or chlorotic areas between veins
  • Stunted plant growth

How Manganese Deficiency Is Diagnosed

Through visual inspection, you can tell if your cannabis plants are suffering from manganese deficiency. Observe the color of the leaves of your marijuana plants. Are they turning yellow? Do you notice veins that remain green? Are there any dead spots observed on the leaves?

Diagnosing manganese deficiency is different from magnesium deficiency when it comes to the age of the affected cannabis plant leaves. Remember that magnesium is considered a mobile element. It means that older leaves tend to show odd signs of problems first and then spread to newer leaves. On the other hand, manganese is more static, which means that the new cannabis leaves are affected first and rarely transfers to older leaves.

Effective Solutions on How to Treat Cannabis Manganese Deficiency

Now that you know the signs of manganese deficiency, it’s time to learn the effective solutions on how to treat this problem. But of course, prevention is still the best step you need to take to prevent this nutrient deficiency from happening.

What is the best solution if your cannabis plants suffer from manganese deficiency? Take a look at the following solutions:

Manage pH Level

If the pH level is too high or your cannabis plants get too much iron, manganese deficiency might be present. That’s why managing the pH level of your growing cannabis is important to resolve this problem.

Note: After manganese deficiency is addressed in your cannabis plants, the yellowing leaves, and brown spots will only stop spreading within seven days. Also, the damaged leaves won’t likely turn green or recover anymore, so pay close attention to other signs of recovery.

Here are some recommendations when managing pH levels:

  • In a soil medium, manganese is well absorbed if the roots have a pH level of 6.0 to 7.0.
  • Some cannabis growers highly recommend keeping the pH slightly lower (6.0 to 6.5) if manganese deficiency is present.
  • In hydroponic systems, the best pH level is between 5.5 to 6.0 so that manganese is well absorbed by the roots.
  • Some marijuana growers keep the pH level of their hydro system between 5.5 to 6.5 since manganese is absorbed at its maximum level if the pH is below 6.0.
  • Once you suspect manganese deficiency, it is important to flush your hydroponic system with clean, pH’d water containing a regular dose of marijuana-friendly nutrients, including manganese. By doing so, it will remove excess nutrient salts or iron that may be influenced by manganese uptake. It helps restore pH levels and will supply your cannabis plants with missing nutrients.

Feed Your Cannabis Plants

If you’re using a soil medium, transplanting your cannabis plants can help provide a new soil base that is rich in manganese to resolve this problem. On the other hand, if you are using a hydroponic system, it is important to feed your marijuana plants by feeding them the right amount of nutrients.

Here’s how to feed your plants in a hydroponic system:

  • Purchase the appropriate fertilizer for your grow medium. Check your local fertilizer store some commercially available hydro fertilizers in liquid or powder form.
  • Follow the manufacturer’s instructions on how to dilute the fertilizer in the water. Don’t go overboard because overfeeding may cause harm to your cannabis plants.


If you learn how to treat cannabis manganese deficiency, it will avoid higher pH levels because this condition most likely occurs due to too high or low pH. When treating manganese deficiency in your cannabis plants, it is important to manage the pH level and keep it within the acceptable range for the weed to draw manganese from the grow medium without any problem. Keep the pH level below 6.0 as much as possible.

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