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How to Fix a Zinc Deficiency in Weed Plants

November 30, 2021
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Afraid you may be facing a problem with zinc deficiency in weed? Many growers think a zinc deficiency is a minor problem that solves itself. Zinc again! If your plant babies aren’t getting enough of this micronutrient, it could cause long-term irreversible damage. 

As scary as it sounds, there's no need to stress—you've come to the right place. We'll unpack what triggers a marijuana zinc deficiency, signs to look out for, and how to treat it. Use our guide to get your plants in-zinc again. 

Let's get started! 

Weed plant with zinc deficiency
Weed plant with zinc deficiency

What is a zinc deficiency?

A cannabis zinc deficiency happens when weed plants lack zinc, an essential micronutrient vital to the development of marijuana plants. It's similar to a manganese or iron deficiency, but a lack of zinc directly affects new growth and renders any vegetation motionless.

Don’t take a zinc deficiency in marijuana lightly—it can cause serious irreversible destruction to your precious flora. The good news is zinc deficiencies are rare. When you diagnose and treat them early, your plants flourish and reach their full potential.

What does zinc do for plants?

Zinc is crucial for healthy growth and development from the moment you plant your cannabis seeds. A zinc deficiency in weed is detrimental to marijuana vitality because this micronutrient plays several essential roles, including: 

  • Assists in the production of enzymes that help plants absorb nutrients and perform photosynthesis.
  • Produces chloroplast, which helps vegetation process light for photosynthesis.
  • Required for the synthesis of auxins, hormones that regulate cell growth.
  • Helps flora process proteins.
  • Aids with metabolizing carbohydrates and essential acids.
  • Used to form the plants' macromolecular autonomy for essential parts like membranes.
  • Plays a role in stabilizing RNA and DNA structures.

Zinc may be a micronutrient, but it plays a major role in ensuring your marijuana plants are in top form. It's essential to know what causes a zinc deficiency weed problem so you can protect your greenery from long-term damage. 

Cannabis zinc nutrient deficiency
Cannabis zinc nutrient deficiency

What causes zinc deficiency in marijuana plants?

Multiple factors can contribute to a marijuana zinc deficiency. Simple errors such as overwatering, imbalanced pH, and excess nutrients can easily trigger this problem. Here are some possible reasons your plants are lacking in zinc: 

Excess pH levels 

Many novice growers make the common error of drenching soil with high pH water, thinking it’ll help their plants flourish. Excess pH levels create an overly alkaline environment to absorb essential nutrients leading to multiple issues, including a weed zinc deficiency. 

pH test
pH test


If you drink too much water, you'll find yourself frequenting the toilet, but plants don't have the option of sprinting to the nearest restroom. Overwatering your plants leads to stagnant water at the roots, resulting in rot and preventing oxygen and nutrient absorption. As roots decay, your plants starve, leading to a cannabis zinc deficiency.

Organic growing

Although it’s good for the environment and your health, growing organic marijuana has its downfalls. The pH range of organically cultivated plants is more vulnerable than plants nourished by chemical fertilizers. Organic growers face a double whammy—the organic flora pH easily offsets, and fixing a weed zinc deficiency in organic plants is challenging. 

Pests or fungus 

Common cannabis pests, including mites, fungus gnats, and inchworms, are difficult to get rid of and contribute to nutrient deficiencies. Root damage is a definite path to a marijuana zinc deficiency, and overwatering isn't the only way to get there. A pest or fungus infection may also cause root damage, starving and eventually killing your plants.

Poor quality fertilizers

Most high-quality fertilizers come with easily absorbable essential nutrients and micronutrients. Some common fertilizers lack micronutrients, and if growers are unaware, their plants experience zinc deficiency cannabis problems. 

Homegrown nutrients pack
Homegrown nutrients pack

Phosphorus overload

A sudden burst of phosphorus causes a weed zinc deficiency—a common issue that hydroponic growers face. Once a hydroponic growing system runs out of nitric acid, it switches to phosphoric acid to keep pH down. Plants take in significant amounts of phosphorus, pushing them into nutrient lockout. 


Stress and cannabis don't pair well together. If your plants are stressed out, temporary nutrient problems like a cannabis zinc deficiency may occur but usually resolve on their own. Possible stress triggers include irregular light cycles, environmental extremes, and plant tissue damage. 

Zinc deficiency symptoms in weed plants

If you want to know how to fix a zinc deficiency in plants, you must first spot the signs. Below is a simple checklist; if you tick most boxes, your plants may lack zinc and other nutrients.

Weed zinc deficiency checklist: 

  • Yellowing between veins (especially on new leaves) 
  • New leaves don't open up or turn yellow 
  • Leaves curl or have burnt tips 
  • Speckled or patchy leaves
  • Stubborn growth—plants don't get taller 
  • Frail, lose buds 

We're about to detail some common symptoms that you should look out for. If you spot these signs, you should work on fixing them ASAP. 


Picture yellow leaves with rusty tinted tips on a weary-looking plant—sound familiar? Nope, it's not autumn; it's chlorosis. It's caused by a lack of chlorophyll which is a green pigment that's essential for photosynthesis. Zinc plays a vital role in forming chloroplast, so chlorosis is typically a sign of a cannabis zinc deficiency. 

You'll generally spot chlorosis in the newer leaves since a weed zinc deficiency affects earlier growth first. If chlorosis is left untreated, your plants experience necrosis, and the leaves die completely. 

Stunted growth

If you notice that your plants are developing slower or their growth is stunted, it could point to a marijuana zinc deficiency. 

Signs of stunted growth typically go in the following order: 

  1. The space between the nodes narrows. 
  2. New growths are packed too tightly, resulting in them becoming tangled. 
  3. Young leaves have a yellow hue or struggle to open up.


If you let out a tiny screech when you see your weed garden, there may be a cannabis zinc deficiency problem. There aren't enough auxins without zinc, which means the hormones regulating cell growth are spread thinly and result in strange-looking plants

You'll spot these abnormalities significantly in younger growth. Newer leaves appear thinner, shriveled, and contorted—resembling a horror movie prop. These deformed leaves usually suffer necrosis and die as a result of a weed zinc deficiency. 


Once the marijuana zinc deficiency symptoms affect your buds, you might as well say your last goodbyes. Buds become light, airy, and dry with little to no aromatics, potency, or visual appeal. Don't worry; you don't have to read the eulogy yet; you can fix a zinc deficiency before it's too late. 

Zinc deficiency weed
Zinc deficiency weed

How to fix a cannabis zinc deficiency

Now that you're equipped to spot the critical signs, let's talk about how to fix a zinc deficiency in plants. Remember that the earlier you act, the better the chances your marijuana greenery will heal and thrive. Zinc deficiencies take a long time to repair, and results aren’t immediate, so patience and strategy are key here. 


Before supplementing a weed zinc deficiency, you must first flush the growing medium. Flushing allows you to remove any nutrient salts that stop your plants from absorbing essential vitamins. It also helps balance pH levels and creates a blank slate for treatments

Flush with pure pH water that contains a cocktail of approximately half the nutrients your plants need, like iron, manganese, and zinc. Zinc is absorbed better with an acidic root environment, so to correct a marijuana zinc deficiency, your pH should be more on the acidic side. 

If you use soil, aim for a pH between 6.0–6.5. Hydro growers should stay in the 5.5–6.0 range. Once the cannabis zinc deficiency clears, soil growers should revert to 6.0–7.0, while hydro plants should sit at 5.5–6.5. 

Replenish with nutrients 

A weed zinc deficiency is rare since it’s found in sufficient amounts in tap water. Growers who use reverse osmosis or heavily filtered water predispose their plants to deficiencies since nutrients are filtered out. 

If you use filtered water, you'll need to set your pH on the more acidic side, then add zinc and other nutrients to your medium. Growers who use tap water and good-quality soil don't need to add more zinc. A balanced cocktail of cannabis-friendly nutrients works well for a cannabis zinc deficiency.

Foliar spray

Foliar is typically used for pest control which could be beneficial if pests are causing your zinc deficiency weed troubles. It's also a fast-acting nutrient feeder. Plants quickly absorb foliar spray via the leaves, making it an effective emergency short-term nutrient deficiency treatment. 

Remember that foliar spray is a temporary treatment and can’t replace feeding and nutrients in the grow medium. To use it for a marijuana zinc deficiency, spray the newer growth to prevent chlorosis while flushing and treating the medium. 

Root care

Roots are the foundation of a healthy cannabis plant. Most times, a cannabis zinc deficiency results from clogged roots due to overwatering, nutrient build-up, or pests. Ensure your roots have easy access to water, oxygen, and adequate nutrients. 

Perform regular checks to make sure the pH is within range, and the root zone stays at room temperature. Keeping the roots in a comfortable environment makes it easier to absorb nutrients and prevent a weed zinc deficiency. 

Chlorosis Treat the grow medium and use foliar spray for the new growth.
Stunted growth Flush and replenish the medium and use structural support to help plants grow upwards.
Abnormalities Prune severely deformed leaves, spray with foliar, and treat the growing medium.
Clogged rootsFlush growing medium, balance the soil’s pH, and ensure roots are at a comfortable temperature—avoid clay-based products. 
Airy/ brittle budsSay a prayer—once the buds are affected, there's not much you can do. You’ll have to flush and nourish the medium and hope for the best next time. 
Yellow curly leaves
Yellow curly leaves

A weed zinc deficiency is treatable 

Zinc is an essential micronutrient, so a weed zinc deficiency causes severe damage if left untreated. Act fast and remain patient since it takes time for plants to recover from a lack of zinc. If you flush the grow medium, replenish it with nutrients, and spray with foliar (if necessary), and you'll see improvements in a week or so.

The key to fruitful plants is to remain observant, consistently take care of your plants, and, most importantly, invest in high-quality cannabis seeds. Shop our range of top-shelf weed seeds, and soon you'll be zinc-ing your teeth into some potent buds. Happy growing! 

About the Author: Kyle Kushman

Kyle Kushman is a legend in the cannabis community. He is the modern-day polymath of pot: cultivator, breeder, activist, writer, and educator. After winning no less than 13 Cannabis Cups, there’s nothing this guy doesn’t know about indoor growing - he’s been there, done it, and is still doing it to this day!

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