Cannabis Zinc Deficiency: Signs, Symptoms and Solution

Zinc is one of the essential micronutrients required for the healthy growth of all plants, trees, and the greenery you see around you. It plays a crucial role in various physiological processes such as enzyme activation, photosynthesis, and hormone synthesis.

In today’s blog, the Growers Choice seed bank will walk you through the signs of zinc deficiency as well as how to fix it to maintain healthy plants. Keep reading to learn how you can prevent zinc deficiency in marijuana plants.

By knowing the ins and outs of a zinc deficiency, you’ll be able to grow Blueberry CBD cannabis plants at home with minimal issues.

Understanding the Role of Zinc in Cannabis Growth

There are a handful of ways in which zinc promotes cannabis growth. As a micronutrient, a certain amount of zinc is needed in marijuana plants to prevent stunted growth. The first way in which zinc benefits cannabis growth is via enzyme activation.

Zinc is a cofactor for numerous enzymes involved in metabolic processes within the plant. These enzymes facilitate biochemical reactions necessary for plant growth, such as photosynthesis, respiration, and protein synthesis.

Speaking of photosynthesis, zinc is crucial for the synthesis of chlorophyll (the green pigment responsible for photosynthesis). Chlorophyll molecules contain zinc atoms at their core—and without sufficient zinc, plants may exhibit reduced photosynthetic efficiency that leads to stunted growth and decreased yields. 

In the same way that people rely on cannabis for stress relief, cannabis plants rely on zinc for their version of stress relief. Zinc helps plants cope with environmental stresses such as drought, high temperatures, and disease. It strengthens the plant’s immune system and enhances its ability to withstand adverse conditions and stressful conditions. Next up we have hormone regulation. As zinc helps the regulation of plant hormones such as auxins and cytokinins, it is responsible for proper cell division, root development, and the flowering of a cannabis plant.

No zinc = no flowering of your Amnesia marijuana plants. Now, that would be a disaster for growers.

The Function of Zinc in Cannabis Plants

We touched on a few of these in the section above, but let’s go over some of the highlights of zinc’s function in cannabis plants. The three biggest takeaways pertain to photosynthesis, stress relief, and hormone regulation.

If your plant’s zinc levels are off, you could see less-than-ideal changes in the growth, development, and health of your marijuana plants. Proper zinc levels are necessary because the nutrient helps with carbohydrate, protein, and chlorophyll production.

Be sure to grow Gorilla Glue marijuana plants in a stress-free environment!

Okay, but what are plant carbohydrates?

It’s wild to think that humans and plants are not so different. Plants, too, rely on carbs to grow to their full potential—but maybe not the bread kind.

Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen atoms, with a general chemical formula of (CH2O)n. In plants, carbohydrates provide energy, serve as structural components, and help the metabolic process.

And what about protein production?

Proteins are vital macromolecules found in all living organisms, including your beloved cannabis plants. In plants, proteins contribute to their growth, development, and overall physiology.

Here are some of the ways that protein benefits cannabis plants:

• protein supports the plant’s physical structure and prevents breakage
• protein serves as catalysts for biochemical reactions in plant cells
• protein is essential for the process of photosynthesis
• plants produce protein to transport molecules to tissues and organs
• protein protects against environmental stress, such as herbivores

Cannabis Zinc Deficiency: Signs and Symptoms

Now you may be thinking that all of this sounds like bad news—but fear not! There are tell-tale signs to look out for when it comes to zinc deficiency in cannabis plants. By watching for these signs, you’ll be able to pick up on a potentially unhealthy marijuana plant. 

The first sign to watch for is the yellowing or browning of plant leaves, which, in fancy science language, is called interveinal chlorosis. While a healthy marijuana plant has green leaves with vibrant notes of color, an unhealthy plant that lacks zinc may show yellow veins on its leaves.

Interveinal chlorosis targets younger leaves first (usually beginning with leaf tips) and eventually moves to more mature parts of the cannabis plant. And speaking of leaves, not only may their coloring appear yellow and brown, but their appearance will also change. You may notice wrinkling, cupping, and/or tearing as your plant has become fragile. 

The key takeaway: brown spots and yellow leaves = bad. These “dead spots” are not the end of the world if you spot them in time and course-correct. The same goes for weak stems. Simply trim or cut the weak part of your plant and focus on the healthy parts.

Stunted Growth in Zinc Deficiency 

The second visible sign to pay attention to is stunted growth. Cannabis plants may appear smaller and shorter than expected for their age. When Growers Choice talks about stunted growth, it also relates to shoot and root growth.

We mentioned earlier that zinc plays a vital role in how cannabis plants flower. With a zinc deficiency, marijuana plants may flower at a slower rate or produce a lower yield. Or, your plants may not flower at all (insert huge gasp!)

Many growers look forward to the flowering stage most of all during the growth process and it would be an awful shame for it to be rather anticlimactic. A zinc deficiency in plants will also lead to root problems, increased susceptibility to disease, and tissue death. Yeah, it ain’t pretty.

Solutions for Marijuana Zinc Deficiency

But what kind of Growers Choice article would this be if we didn’t offer help? A pretty useless kind, if you ask us. We don’t mean to instill fear in your hearts—we mean to help you with plant development and nutrient solutions. Yes, there are solutions for cannabis zinc deficiency! Not all hope is lost and you may be able to save your cannabis plant after all.

The first solution is what Growers Choice calls soil amendment. This is where you incorporate zinc-containing amendments into the soil to increase its zinc content. You may use zinc sulfate, zinc oxide, or other zinc-containing fertilizers. 

For best results, follow the recommended application rates provided on the fertilizer packaging or based on soil test results to avoid over-application, which can lead to toxicity. Too much zinc can also be a bad thing. Annoying, right?

Another method to increase the presence of zinc in plants is to use a foliar spray. Foliar sprays provide a quick and effective way to deliver zinc to plants by overriding soil uptake issues. Use a zinc chelate or other readily absorbable form of zinc for foliar application and apply the spray during cooler hours to minimize leaf burn. If growing indoors, lower the intensity of your grow lights to prevent light burn.

How to check for all nutrient deficiencies

We’ve talked a lot about zinc deficiency in weed plants—but what about all the other nutrients a cannabis plant needs? What about iron deficiency? Or magnesium deficiency? There’s one way to keep tabs on all of that, and it’s called a pH adjustment of the soil. Adjust the soil’s pH if it is outside the optimal range for zinc uptake (6.0 to 7.0). Zinc availability to plants is highest in slightly acidic to neutral soils.

If the soil pH is too high (alkaline), consider amending it with elemental sulfur or acidic fertilizers to lower the pH and improve zinc availability. This method also works for calcium deficiencies and manganese deficiency. 

The annoying but equally wonderful thing about plants is that no two are the same. Some marijuana plants respond to a foliar spray while another batch may respond to a pH adjustment for a nitrogen deficiency. It’s very much a trial and error process to check the deficiency in cannabis plants. On the bright side, checking for brown spots can be done in a matter of seconds.

Frequently Asked Questions

Growers Choice understands that the essential nutrients of weed plants come with a lot of questions. So, we’re going to open it up to some frequently asked ones by cannabis growers of all levels—even experienced growers.

What are the first signs of zinc deficiency in cannabis plants?

When doing a scan of your entire plant, scope out the younger, immature leaves first. These are the ones that will show the first signs of zinc deficiency in plants. These baby leaves may not grow due to slow growth, or they may show brown spots and weak stems.

What causes twisting leaf blades in marijuana plants?

And what exactly are twisting leaf blades? This is when leaf curling (also referred to as leaf rolling) occurs on your marijuana plant. It can be caused by environmental stresses, pests, diseases, and genetic factors.

Or, in this case, cannabis zinc deficiency if the vital nutrients are not met.

To be fair, leaf curling is not a direct sign of zinc deficiency in weed plants. It could be many other things including temperature stress, water stress (over-watering and under-watering), and herbicide damage.

Think of your Critical Mango weed plants as babies. They need ample water, nutrients, sunlight, and airflow.

How can zinc deficiency be prevented in cannabis plants?

There are a few ways to prevent zinc deficiency in plants so long as you’re a proactive plant parent. The catch-all way to check for proper nutrient absorption and deficiency is via the pH balance of the soil. 

Before moving on to more complex steps, make sure your cannabis plant has balanced nutrition. If not, it could cause a sulfur deficiency, a copper deficiency, or a deficiency of any kind. A balanced mix of micro and macronutrients leads to optimal plant health, which is exactly what you want as a grower hoping for a serious yield.

The next step you might take is to apply zinc-containing fertilizers (such as a foliar spray) or soil amendments to increase the absorption of zinc. You might add organic matter to the fertilizer (such as egg shells) to boost the overall nutrients. Think of composting! When composting, you combine organic matter in a bin and eventually add it to plant soil. You could use avocado shells, coffee grounds, pet hair, grass trimmings—it’s a long list!

Help Is Right Around the Corner

Any further questions you may have about nutrient deficiencies—yes, even a potassium deficiency—can be answered on the Growers Choice website. We feature an educational blog that walks you through the process of optimal growth for cannabis plants.

Might you be interested in growing Critical Purple weed seeds? These plants are great for relaxation and helping you get more restful sleep.

Get your hands on our cannabis seeds and start your growing journey today! We strive to provide the best information on healthy cannabis plants from the point of germination to harvesting your buds.

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