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All The Different Cannabis Deficiencies

Written by Ed Rushford Jan 20 2022

All The Different Cannabis Deficiencies

Let’s delve into the murky waters of cannabis deficiencies today and show you how to identify them, treat them and prevent them for the future.

A cannabis plant is resilient, but it will lose health and vigor if it is starved of essential nutrients. It is possible that if this is not treated, plants will cease developing or even die. Because deficiencies in cannabis can be challenging to spot, Premium Cultivars has put together a quick guide on some crucial factors to keep in mind when it comes to cannabis nutrient deficiencies.

Overview of cannabis deficiencies

Various nutrient deficiencies can harm cannabis plants and extremes throughout their growth, whether cultivated indoors or outdoors. To grow and develop properly, cannabis plants require different specialized nutrients. Understanding the indications and symptoms of nutrient excesses and shortages is critical when cultivating cannabis. People sometimes confuse deficiency with other cannabis plant problems, and a misdiagnosis or incorrect treatment can potentially destroy your plants.

Novice growers are going to run into an issue or two. Thankfully, cannabis plants are hardy and can withstand pests and poor circumstances for some time. However, there will be consequences if the problem is not addressed quickly. Overreacting is one of the most common mistakes newbie growers make.

Nutrient requirements for cannabis

Like any other plant, cannabis plants have specific conditions for reaching their highest growth and production levels. The regular supply of vital nutrients for cannabis growth – during each step of the plants’ life cycles – is required for recreational and commercial growers to achieve a profitable and repeatable yield. The required nutrients can be divided into two groups: macronutrients are necessary in larger quantities, and micronutrients are required in smaller amounts. However, all nutrients are essential for plant health and crop production.


While oxygen, hydrogen, and carbon are hardly in short supply in soil, water, or air, three other macronutrients are essential in larger quantities.

1. Nitrogen

In cannabis growing, nitrogen deficiency is a common problem. Nitrogen is predominantly consumed during the vegetative phase and is required for chlorophyll formation. Plants cannot photosynthesize correctly, and leaves turn yellow as stores are depleted from lower fan leaves.

In summary, Nitrogen is important for:

  • Plant growth, leaf development, and protein production.
  • Nitrogen is essential for chlorophyll that gives plants their green color and is needed for photosynthesis.

2. Phosphorus

Phosphorus is essential for a cannabis plant’s photosynthesis and reproduction. It is required in significant quantities during flowering to form resin. Phosphorus deficiencies are uncommon because it is abundant in feeding solutions and grow mediums; yet, lockouts due to pH imbalances can still occur.

Phosphorus is beneficial for:

  • Root, blossom, and seed development.
  • Energy movement between cells and throughout the plant.
  • Photosynthesis requires it.

3. Potassium

Potassium is crucial for flower production throughout the blooming season. In addition to being necessary for plant growth, potassium also aids in pest and disease resistance, enhancing a cannabis plant’s defenses and general performance. Potassium plays an important role in how plants spread carbohydrates and evaporate water.

Potassium is extremely beneficial, it:

  • Helps the plant absorb water.
  • Regulates the stomata’s opening and closure.
  • It is needed to generate Adenosine Triphosphate (ATP), which drives several activities in the living cell.

Tip: Adding nitrogen can reduce potassium intake and vice versa.


Cannabis plants require far fewer micronutrients than macronutrients. They are necessary for the survival of plants and thriving crops.

1. Calcium

Calcium is required for cell development and strength in cannabis plants. Cal insufficiency is less of an issue because the pH levels in soil growth are more significant than in hydroponics. Calcium deficiencies can occur when the soil or grow medium is overly acidic, or the growing environment is too cold and damp. Lack of transpiration and other nutritional issues can result in calcium deficiency.

Calcium is essential for:

  • Transporting additional nutrients requires Calcium.
  • General nutritional absorption.

2. Magnesium

Magnesium is an immobile nutrient that helps a cannabis plant convert light into usable energy, making it an essential part of the photosynthetic process. Mag is the most critical component of chlorophyll, as it permits the plant to produce carbs and sugars. Low pH means that cannabis plants can’t absorb magnesium. This causes the cannabis plant to suffer.

Magnesium helps cannabis plants, it:

  • Aids chlorophyll production and photosynthesis.
  • Assists with nutrition metabolism and transport throughout the plant.

3. Sulfur

Cannabis plants can suffer from a Sulfur deficit on rare occasions. Sulfur encourages the formation of chlorophyll, oils, terpenes, and the efficient use of nitrogen. Sulfur deficiency has symptoms similar to nitrogen deficit, with the yellowing of fresher foliage being the most noticeable. It is most troublesome during flowering when badly damaged buds begin to die from a lack of protein.

What does sulfur do?

  • It’s neccessary for transporting chlorophyll around the plant
  • Aids in the metabolism of plants
  • It is necessary for the transfer of other nutrients

4. Iron

Excesses or other nutrient deficiencies can cause an iron deficiency. Iron deficiency causes yellowing near the top of the plant. A common cause of iron deficiency is overwatering or pH imbalance. On the other hand, cannabis plants can swiftly recover with the right treatment.

5. Copper

You only need small amounts of copper and excess copper can be harmful to plants. Although most grow mediums, including soil, do not contain copper, plants can acquire it through water. Copper aids in the breakdown of carbohydrates and is necessary for healthy bud development. If the shortage worsens, it might have a significant impact on yields.

Tip: Before using your grow medium, inspect or analyze it to see what minerals it contains.

6. Zinc

Zinc helps to form branches stems and the general structure of the plant. It strengthens leaf membranes and provides plants with their toughness. Zinc deficiency causes enzyme dysfunction, resulting in tiny plants with minimal yields. Changes in leaves, shown by compact groupings of withering, yellow shoots, are clear indicators.

Tip: Resolving zinc deficits can be as simple as using a cal/mag solution with trace elements.

7. Manganese

Manganese deficiency is a rare occurrence. On the other hand, this micronutrient is essential for healthy plant growth. Manganese’s key functions include photosynthesis and nitrogen metabolism. It also uses iron to make chlorophyll, which means high iron levels might cause a lockout.

Tip: When adding manganese, be cautious because iron levels can become unbalanced.

8. Molybdenum

Enzyme processing depends on molybdenum, even though cannabis plants only require a small amount of this nutrient. Molybdenum deficiency exhibits similar symptoms to magnesium and nitrogen deficiency which can make it difficult to diagnose. Low pH and cold temperatures are the most common causes of molybdenum insufficiency.

Tip: If your plants have a molybdenum deficiency, flush the system and reset the pH.

9. Boron

This nutrient helps cannabis plants develop a healthy structure and strengthen cell walls and protective leaf membranes. Plants dry out too much and don’t get enough water, which is a problem. Plants with a boron shortage are more likely to have additional deficiencies at the same time, making diagnosis difficult.

Tip: To minimize boron deficiency, maintain greater humidity levels.

What are the early signs of cannabis nutrient deficiencies?

When people think of cannabis plants, they usually visualize large frosty buds surrounded by bushy, lush green leaves. If there are any issues, the plant will let us know through various physical changes. These signs are usually visible through the leaves of the plant. Here are the early signs of nutritional deficiency to look out for:


Yellow or brown leaves are a key indicator of nutrient deficiency.

Discolored Cannabis Leaves
Deficient Cannabis Leaves

Discoloration can be difficult to pin to a single deficiency. Multiple nutrient deficiencies can cause leaf discoloration, including:

  • Nitrogen deficiency manifests itself as the yellowing of older leaves, the entire plant, curled leaves, or few buds.
  • Phosphorus deficiency – In addition to the significant yellowing, cannabis plants with a phosphorus deficiency may have a dark purple color and blackish patches on the leaves. This problem can manifest as cannabis purple stems.
  • Potassium deficiency – Manifests itself in various ways, including dull leaves, brown patches, and brownish leaf tips that resemble scorched.
  • Iron deficiency- Check for yellowing in between the leaf veins. 
  • Copper deficiency – Indicated by dark blue foliage, bright yellow or white tips, and leaves with a metallic shine. Curling leaves are also a possibility.
  • Manganese deficiency – Symptoms of manganese deficiency begin with new growth and spread to older leaves, culminating in dead patches on all leaves.
  • Zinc deficiency – Causes the leaf tips to turn a burnt brown color and rotate 90 degrees to one side.


Leaves curl, droop, and eventually drop in various cannabis nutrient deficiencies. This type of stunted growth is usually caused by one or more of the related nutrient deficiencies:

  • Magnesium deficiency – Symptoms appear as early as six weeks after growth, causing rusty patches on the leaves and, eventually, the entire plant to droop.
  • Calcium deficiency – If a cannabis plant is deficient in calcium, you’ll observe curled lower leaves accompanied by withering root tips.

Diagnosing and solving cannabis deficiencies

Identifying developing plant health concerns may be challenging since they might be misunderstood. The yellowing of the leaves, for example, is a common symptom of several deficiencies. It might leave the problem unsolved, and the plant could even acquire new issues due to erroneous treatment.

Overwatering and keeping your plant in a chilly area may cause yellowing and browning of the leaves. Deficiencies in nutrients and minerals can be mistaken for this. Preparing for the grow with the appropriate circumstances, a consistent grow medium, and trustworthy fertilizers help a producer prevent cannabis deficiencies.

A grower plagued by nutrient deficiency issues while growing in 5-liter soil containers may benefit from a 20-liter container. More extensive and more robust root networks and a more comprehensive plant with less chance of deficiency are possible because the cannabis roots have a larger supply of nutrients to draw from. Using organic nutrients that take longer to break down might also be a good idea. Slow-release organic nutrients are highly recommended and should help avoid nutritional deficiency.

Refilling the fertilizer reservoir in hydroponic systems more regularly minimizes the chance of running short on an essential nutrient.

Nitrogen Deficiency

Among the macronutrients, nitrogen is one of the most notable. Not only does nitrogen make up a significant portion of plant proteins, but it also plays a critical role in photosynthesis, particularly during the later growth phases.

Effects of Nitrogen Deficiency

The leaves might become pale, yellow, curled, and finally fall off with nitrogen deficiency in cannabis. The leaves closest to the plant’s base may be the first to show it. The plant’s yellowing might spread upwards. Leaf discoloration and browning are possible. With lesser yields and fewer bud points, blooming may appear to be occurring quicker.

Diagnosing Nitrogen Deficiency

The yellowing of your cannabis plants’ foliage is one of the most common indicators of cannabis nitrogen deficiency. Your plants’ older and lower leaves will turn yellow, wilt, and fall off as the season progresses. The younger leaves higher up the plant will begin to take the nitrogen from these older leaves. The plant prioritizes upper leaves because they get the most light and are therefore more important for photosynthesis.

Nitrogen Deficiency
Symptoms of Nitrogen Deficiency

Although this is not always a problem, lower and older leaves will turn yellow and fall off when nitrogen is directed toward the buds when the growing season nears the end. Your plant’s leaves should be a cause for concern if they turn yellow and fall off quickly during the vegetative phase. There should be more concern if this yellowing spreads up the plant.

Solving Nitrogen Deficiency

You can find nitrogen in various pre-mixed nutrients at the market, or you can use nitrate of soda or organic fertilizer, both effective nitrogen sources. You can find it in almost every plant nutrient, so this is not surprising. If you have not been giving your crops any nutrients, try giving them a little more nitrogen to see if it helps the plant recover.

Nitrogen deficiency in cannabis is unlikely if you have previously used nutrients. You must discover what else is contributing to the yellowing of your plants if you have been supplementing them with nitrogen for even a short period.

Phosphorus Deficiency

Due to its role in the photosynthetic process, cannabis requires phosphorus at lower levels during the vegetative stage. Yet, it is just as critical as other macronutrients. As a component of the plant’s energy use system, phosphorus aids in transmitting energy from light to the storage places where sugars are needed for new development. It implies that phosphorus helps carry sugars to where further growth is required.

Effects of Phosphorus Deficiency

Phosphorus deficiency in cannabis may hurt the health of your plants and the crops they can produce. Cannabis phosphorus deficiency may cause various symptoms in your plant, so be on the lookout for them. Phosphorus deficiency cannabis typically begins to show with plants’ lower, older leaves. A lustrous sheen and deeper green, blue, and grey colors may be seen on these leaves. The leaves will also begin to become a darker shade of brown and purple due to this color shift. In addition, the leaves will start to dry out and thicken. The plant’s stems may also begin to change color.

Diagnosing Phosphorus Deficiency

There is a good chance that if you have ever seen dry leaves with dark discoloration, you have witnessed Phosphorus shortage. Additionally, it may cause petioles to develop red/purple collations (dead patches and leaf stems). The leaves may become a darker shade of blue or green.

Phosphorus Deficiency
Symptoms of Phosphorus Deficency

Phosphorus shortage significantly reduces both vertical and horizontal development if left untreated. You can cover the leaves with dark, black patches. Curled and drooping leaves may seem metallic purple or dark bronze.

Solving Phosphorus Deficiency

When the pH of the roots is too low, it might lead to a phosphorus shortage. If you want to know how to fix phosphorus deficiency, the root pH should be between 6.2 and 7 to maximize nutrient uptake. When signs of deficit appear, it is best to aim for a soil pH in this range. By using pH up and down solutions, you may accomplish this goal.

You can also guarantee phosphorus levels by using an organic fertilizer with enough essential nutrients. Likewise, you can supplement the soil with additional sources of phosphorus to maximize exposure. Warm casting, fish meal, crab shells, and soft rock phosphate are all excellent sources of phosphorus. Phosphorus deficit may also be due to excessive irrigation or compacted soil. To prevent this, make sure you water your plants appropriately.

Another aspect to consider while obtaining optimal phosphorus levels is the temperature. Because of lower and colder temperatures, you can reduce nutritional absorption by cannabis plants. There may be detrimental consequences if the temperature drops below 15 degrees Celsius.

Potassium Deficiency

Potassium deficiency in cannabis may be lethal since it is more likely to show up in the blooming stage. Check to see whether you can deal with a problem if it happens.

Effects of Potassium Deficiency

Now and again, soil and other media suffer from deficiencies. The brown or yellowing of the leaf tips and margins is the most typical effect. These will curl over time and seem scorched, much as an iron deficit would. Stretching is another thing that may attract concern. It weakens the stems of the plants surrounding it if one plant seems taller than the others.

Leaf spottiness will be the first sign to show. The first things you will notice are those brown necrotic areas. If you don’t get rid of the spots, others will appear, specifically chlorotic ones with a white appearance. In contrast to many defects, the veins of the leaves will retain their green color. The petioles and stems will change color, with crimson tones appearing.

Even though the plant had previously stretched out, it was not growing. As a result, the plant’s growth slows. Foliage will shrink in size, signaling a critical stage of the deficit. Potassium deficiency cannabis is highly migratory, making it difficult to predict. Unlike other deficiencies, they travel quickly around the plant. In the end, this one will spread to the fan leaves, where it is most likely to cause their death.

Diagnosing Potassium Deficiency

A cannabis potassium deficiency is most often seen in older leaves, although it isn’t always the case. You can sometimes see the symptoms near the top of the plant.

Potassium Deficiency
Symptoms of Potassium Deficiency

It is common for leaves to become yellow, brown, or burned at the margins and tips when they lack potassium. Although the scorched edges may seem like nutrient burn, they also become yellow in the borders.

Solving Potassium Deficiency

In some instances, growers prefer flushing their grow medium to ensure that they are not dealing with additional difficulties, such as overfeeding, which may interfere with Potassium absorption. A top application of chicken dung, potassium-rich nutrition, or foliar feed may aid. Organic kelp is an excellent foliar feed for plants.

Magnesium Deficiency

As a micronutrient, magnesium is immobile. Chlorophyll is made from it, which is crucial for photosynthesis. Photosynthetic processes like chlorophyll and photosynthesis are utterly impossible without magnesium.

Effects of Magnesium Deficiency

Often, magnesium deficiency in cannabis is a common cause of stunted development. No producer wants this shortage, whether early in vegetative growth or late in the bloom cycle. Luckily magnesium deficiency cannabis may be prevented and treated with expert guidance.

Diagnosing Magnesium Deficiency

Deficiencies in this immobile nutrient tend to show up in new leaf development. It begins with yellow dots on the leaves, which gradually become brown and die. Leaf interveinal chlorosis (interveinal rust) is a yellowing of the leaf between the veins.

Magnesium Deficiency
Symptoms of Magnesium Deficiency

Cannabis magnesium deficiency, if left untreated, may drastically reduce a plant’s capacity to produce any kind of harvest whatsoever.

Solving Magnesium Deficiency

The first step in solving a magnesium deficiency in cannabis is to flush with water with a pH of 6.0. It should work with any kind of fabric. Afterward, you will need to produce a pH-balanced meal for your plant. Cocoa (6.0) and Hydro (5.5-6.0) soils are ideal for growing cocoa. Add a high-quality, cannabis-specific magnesium supplement to the usual brew of nutrients.

Calcium Deficiency

In plants, calcium is an immobile micronutrient that plays a critical function. The cell walls get strength from calcium. Consequently, calcium deficiency cannabis may cause new development to be twisted or lacking in structure. Nitrogen and sugars are better able to move through the plant when calcium is present.

Effects of Calcium Deficiency

The proper development of cannabis is dependent on the complicated interplay of several components. A lack of calcium may slow growth in both vegetative and reproductive stages. As a master grower, it is essential to identify and fix problems like these.

Diagnosing Calcium Deficiency

Your cannabis plant’s leaves will show brown or bronze splotches or patches when it is deficient in calcium.

Calcium Deficiency
Symptoms of Calcium Deficiency

In addition to yellowing (though leaves don’t always turn yellow), it is often connected with under LEDs; the splotches might sometimes seem purple.

Solving Calcium Deficiency

Supplementing with calcium and magnesium is a quick and straightforward fix. Check to see if your feed pH has grown too alkaline. Instead of utilizing a Ca/Mg supplement, consider feeding your horse a teaspoon of hydrated lime mixed with 4 liters of water. Incorporate extra powdered dolomite lime into your growing medium to avoid cannabis calcium deficiency (prevention is better than cure).

Boron Deficiency

Boron (chemical symbol ‘B’) and calcium are essential for healthy cell walls and efficient cell division. The nutrient boron is a macronutrient that is immobile. Boron deficiency is rare since cannabis only needs it at modest levels. It is present in most high-quality soils and compost.

Effects of Boron Deficiency

As a result of boron deficiency in cannabis, the development of new leaves is slowed and stunted. The leaves’ inside will have a light brown tint.

Diagnosing Boron Deficiency

Abnormally thick growth tips and new leaves with brown or yellow spots are the first indicators of a cannabis boron deficiency.

Boron Deficiency
Symptoms of Boron Deficiency

A boron deficiency in cannabis causes aberrant and delayed development in the top cannabis leaves. Inappropriate growth, twisted growth, and even death may occur at the terminals of plants. Wrinkled or curled new leaves are possible.

A boron deficit may also harm plant roots, resulting in sluggish or unhealthy development. The stems might grow brittle or hollow, depending on the weather. When a plant is underwater or experiencing low humidity, boron deficiency is more likely to occur.

Solving Boron Deficiency

Add more Boron to your growing media once you have flushed it. Feed your plant with 3-4 liters of water and a teaspoon of Boric acid.

Copper Deficiency

Semi-mobile macronutrient copper is a crucial component of the plant diet. It aids in the use of nitrogen by the plant and glucose metabolism. The copper shortage is rare since most growing media and plant foods contain enough amounts of the mineral.

Effects of Copper Deficiency

A case of copper deficiency in cannabis is quite uncommon. When this happens, it may have a detrimental influence on your crop because it prevents the buds from ripening. It is conceivable that copper insufficiency is caused by a lack of copper in the soil or water, but this is more likely due to a pH issue at the roots of your crops, limiting the number of nutrients they can absorb.

Diagnosing Copper Deficiency

Leaf signs of a cannabis copper shortage include dark leaves with blue or purple hues. Unlike the darker leaves, the tips and margins of leaves become a light yellow or white color.

Solving Copper Deficiency

A copper shortage is the first thing you should look into if you suspect that your plants lack this mineral. One of the essential aspects of pH is its role. A soil pH of 6.0 to 7.0 is ideal for the absorption of copper by your cannabis plant, which grows in soil. Try a pH range of 5.5 to 6.0 in hydroponics systems instead.

Iron Deficiency

In terms of macronutrients, iron is a “semi-mobile macronutrient.” It is required when you use nitrates and sulfates. Chlorophyll synthesis needs the presence of iron. Deficiencies in iron may arise if the pH is out of whack. Deficiencies in Zinc, Manganese, or Copper may also lead to this condition. Several metabolic and energy-generating functions need the presence of iron.

Effects of Iron Deficiency

Iron helps cannabis to turn carbon dioxide and light into food. Another reason why leaves develop so quickly is because of this element’s ability to promote nitrogen absorption. Cannabis iron deficiency affects the plant’s capacity to store and build energy.

Diagnosing Iron Deficiency

You might see the first signs of iron shortage in developing new plants. At the bottom of fresh leaves, interveinal chlorosis may occur. After that, older leaves and growth will show the same signs.

Iron Deficiency
Symptoms of Iron Deficiency

You can detect Iron deficiency by the general yellowing of the leaf veins.

Solving Iron Deficiency

Flush the growing medium with a pH of 6 water. This procedure removes any extra minerals that may impede the absorption of iron.

The next stage uses an all-purpose nutrition solution for cannabis

in the next watering. As a precautionary measure, it is essential to monitor the pH of the growing medium often.

Manganese Deficiency

Manganese is a micronutrient that you cannot transfer from one place to another. In addition to nitrogen utilization, respiration, and photosynthesis, it also plays a role in these processes. Manganese aids root cell formation and protect roots from harmful bacteria. Manganese deficiency is a rare occurrence. Excess iron or a high pH is often implicated.

Effects of Manganese Deficiency

You can often tell manganese deficiency in cannabis by yellow leaves that quickly deteriorate and become brown—immobility and confinement to young, fresh growth hallmark this rare disease. You can misinterpret manganese deficiency in cannabis plants as something else. Manganese insufficiency is not acceptable.

Treatment for manganese deficiency typically involves many weeks of trial and error on the part of the farmer. Growth has slowed to a trickle at this point. It will seem like a withering patchwork of faded green, yellow and brown on the top layer of the plant.

Diagnosing Manganese Deficiency

Like other immobile nutrient deficits, manganese insufficiency tends to show up as a pale discoloration at the base of new plant growth. In the long run, this may extend to the tips of the leaves, when brown (necrotic) blotches begin to form.

Manganese Deficiency
Symptoms of Manganese Deficiency

To make the interveinal parts seem yellow, the edges and veins of the leaf will appear green in color.

Solving Manganese Deficiency

Clean, pH-corrected water with frequent doses of cannabis-friendly nutrients, including manganese, may cleanse your system if you anticipate a manganese shortage in your cannabis plant. Iron and nutritional salts that may interfere with manganese absorption may be removed and any minerals that may be lacking from the soil.

Molybdenum Deficiency

Molybdenum is a micronutrient that may move around. Enzyme systems that convert nitrates to ammonium molecules rely on the normal functioning of this enzyme. There are few and far between actual flaws that you can remedy.

Effects of Molybdenum Deficiency

Anemia caused by molybdenum deficiency in cannabis is very uncommon. However, if it reaches your cannabis plants, it might be the start of the end. If your cannabis is suffering, you don’t have time to waste. You can address sick cannabis plants immediately. Ignore it at your own risk!

Diagnosing Molybdenum Deficiency

Initial symptoms may resemble a shortage in nitrogen (yellowing of older, lower leaves). Spots and streaks may appear on the leaves.

Molybdenum Deficiency
Symptoms of Molybdenum Deficiency

Although the leaves may begin to show a characteristic orange, red, or pink hue along the margins, this color will gradually travel into the center of the leaf as a symptom of a molybdenum shortage. Some leaves have a darker center, while others have a lighter center.

Solving Molybdenum Deficiency

Clean, pH’d water with a regular dosage of cannabis-friendly minerals, such as molybdenum, may be used to flush out a molybdenum shortage in a developing cannabis plant. Removing salts that may be impeding the absorption of molybdenum and bringing the pH back to an average level are two of the benefits.

Silicon Deficiency

Silicon has gained a lot of interest in recent years because of its inability to be transported. There are very few people that have an actual deficit in silicon. As a result of the mineral’s ability to reinforce cellular walls, it promotes robust plant development.

Effects of Silicon Deficiency

However, even though it is exceedingly unusual, silicon deficiency cannabis might prevent plants from growing strong leaves, roots or stems. There is a reduction in photosynthesis, which reduces the yield in the end. On the other hand, silicon is not a material that plants can easily transport.

Diagnosing Silicon Deficiency

If you are looking for silicon deficiency symptoms, insect infestations and bacterial and fungal illnesses are more frequent when silicon is deficient.

Solving Silicon Deficiency

Silicon supplements are available, although most farmers utilize them to produce more potent plants rather than to remedy a deficit.

Sulfur Deficiency

Sufficient sulfur levels might be difficult to tell apart from magnesium or nitrogen insufficiency in a plant’s vegetative and blooming stages.

Effects of Sulfur Deficiency

The plant’s growth slows down whenever the leaves thin down and become more brittle. As a result, the leaves will be smaller as well. At this point, buds start dying, and the plant’s development may stall.

Diagnosing Sulfur Deficiency

Chlorosis (yellowing of leaves) is the most common sign of a cannabis sulfur deficiency; however, it might be mistaken for a nitrogen deficiency at first.

Sulfur Deficiency
Symptoms of Sulfur Deficiency

There may be a pinkish red or orange tint on the underside of the leaves. A blossoming plant may begin to lose its buds. Most deficiencies that lead to leaf yellowing start at the tips, while a sulfur shortage progresses backward instead.

Solving Sulfur Deficiency

Ensure your sulfur isn’t being sucked out of your water by checking and correcting your pH. It may take several days before you see improvements in your crop after you cure the issue with sulfur.

Zinc Deficiency

Proteins and other macromolecular structures, including membranes, are built by the cannabis plant using zinc. It is also essential to control enzyme activity. By stabilizing DNA and RNA structures, zinc acts as a co-factor in gene expression and is vital for the growth hormone auxin to function correctly.

Effects of Zinc Deficiency

During a cannabis zinc deficiency, older sections of the plant cannot transfer zinc stores from one area to another, as they do with nitrogen or phosphorous. As a result, zinc shortage is most noticeable towards the top of the plant.

You may notice when a plant is not growing as quickly as it should. The distance between nodes inside a cell is shrinking. In contrast to previous growth shoots, the new ones seem hesitant to open up. Shoot tips will gather and wrinkle up near one another due to repeated use. Leaves will become yellow from the veins as they eventually open up and extend out.

Diagnosing Zinc Deficiency

Interveinal chlorosis is common in young leaves and new plant development. Wrinkled, yellow, and twisted blades of the cannabis leaf may be seen on the plant.

Zinc Deficiency
Symptoms of Zinc Deficiency

When you expose the leaves to sunlight, they will become a yellowish-brown tint. They can turn 90 degrees in any direction.

Solving Zinc Deficiency

A last-ditch effort is to add zinc sulfate, Zinc chelated Zinc, or zinc oxides. There are various sources for these, based on whether or not you want to utilize chemical fertilizers or remain fully organic. Always remember that less is more when it comes to producing cannabis.

About half of the Zinc needed by cannabis may be found in ordinary tap water. If you’re confident that your soil is high quality, you can rule out most of the most severe problems.

Reverse osmosis water might be dangerous if you don’t know what you are doing. To begin, add a Cal-Mag mix to your water to act as a water buffer. You may quickly discover a high-quality Cal-Mag supplement that includes trace elements if you look through the many commercial alternatives available.

After eliminating it as a source of zinc deficiency, it is time to flush. A proper flush eliminates salt buildup from the roots and flushes out stale water pockets. Adjust the feed a little bit more leniently. Your pH meter should be calibrated and working correctly.

How to correctly feed cannabis plants

Fertilizer companies typically give their clients a cannabis nutrient deficiency chart. To ensure that your plants get the proper nutrients at the right time, you need to know how to read these graphs. A typical feed chart shows a 12- to the 13-week growth cycle. The x-axis of the cannabis deficiency chart will generally include the weeks of the process, which may additionally contain information such as the photoperiod for each week and more.

Your feed chart will tell you exactly what nutrients your plants need and how much to give them when it comes to fertilization. Once a week, most fertilizer companies will offer you a feed-to-water ratio. Additionally, specific feed charts may include a PPM range for their products. PPM meters can be used to assess nutrients before feeding for greater precision.

Checking the conductivity and PPM of your soil after feeding your plants is usually a good idea to ensure that they receive nutrients adequately.

How to prepare cannabis nutrients to avoid cannabis deficiencies

You don’t want to risk your yield by making fertilizer application errors. However, feeding your cannabis plants is a simple process. To get started, follow these simple steps:

  • Ensure your water is ready before you begin. Increase root absorption by heating your water to roughly 22°C if feasible.
  • Stir in the nutrients once they have been added, following the directions on your fertilizer. If you want to ensure accuracy, you should use a PPM or EC meter.
  • If necessary, use a nitric or phosphoric acid supplement to lower the pH of your feed.
  • After setting your PPM, pH, and temperature at the optimum levels, feed your plants and check your runoff with an EC or PPM meter to ensure they are getting the nutrients they need.

Feeding cannabis

Depending on your cannabis plant’s stage, it will require different nutrients to thrive. The following is a breakdown of each step and what you should be feeding your plant with:


It is crucial to nurture cannabis seedlings in a warm, humid environment since they obtain all of their nutrients from the seed then absorb water through their leaves while their root system grows.

Until your seedlings are around 3–4 weeks old, you will not have to start feeding them. It is because they have not yet produced 3–4 genuine leaves.


During the first week of a seedling’s vegetative development phase, some gardeners choose to start their plants on a light 2:1:2 fertilizer (there is that NPK ratio again). If you want to avoid nutrient burn, this is an excellent approach to get your plants used to their fertilizer. However, some gardeners have seen fantastic results using a 4:2:3 fertilizer to get their plants off to a fast start.

As soon as your seedlings have sprouted, you will want to raise their fertilizer levels to help them grow robust, lush leaves. At this point, most growers use a 10:5:7 fertilizer. The higher nitrogen levels will help your plants grow lush, green leaves and enough buds for blossoming.

Lowering your nitrogen levels and prepping your plants to transfer to their bloom booster is an intelligent option after the vegetative period. A 7:7:7 fertilizer is commonly used in the final week of vegetative growth.


As a result, flowering cannabis plants require less nitrogen and more potassium. Most gardeners give their blossoming plants a 5:7:10 fertilizer during the first two weeks of flowering. Potassium concentrations should remain consistently higher than the rest from now on, as is standard procedure. Most growers will be utilizing a 6:10:15 nutrition solution by the mid-flowering stage.

Before harvest, farmers would drop their fertilizer levels during the last few weeks of blooming to ease the transition. A softer fertilizer with an NPK ratio of 4:7:10 is popular. Find out more on how to prevent a cannabis flowering deficiency – it’s crucial to solve these issues at later stages of the grow cycle particularly.

How to amend cannabis nutrients in case of cannabis deficiencies

While organic nutrients are not required for cannabis plants to avoid nutrient deficiency, one of several benefits of using them would be that you avoid overfeeding. It occurs because organic nutrients are crafted to be broken down by the soil’s microorganisms rather than being fed directly to the roots.

Slow-release powdered nutrients reduce the likelihood of cannabis nutrient deficiencies since they take longer to break down and are thus more readily accessible to your plant when it needs them. However, it does not imply that organic nutrients are superior, however.

However, if you are dealing with a heavy feeder, you may have to utilize organic tea to make up for the lack of nutrients delivered slowly from organic foods.

Keep an eye on your nutrient solution’s pH and ppm levels to ensure that your plants grow large and healthy even if you are using synthetic fertilizers or any other product you choose or have on hand.

Autoflowering or photoperiodic cannabis plants may suffer from nutrient deprivation; therefore, treating them with the correct quantity of light, fresh air, and nutrients is an art form. To ensure that your plants get all the nutrients and trace elements they require, you must know what they need.

Cannabis nutrient deficiencies in hydroponics

While hydroponics is actually more beneficial for feeding cannabis nutrients, cannabis deficiencies are still possible in hydro grows.

Cannabis deficiencies during the vegetative stage in hydro

Depending on the cannabis plant’s development stage, it will need a varying amount of nutrients. It is more likely to find cannabis plant problems during the vegetative phase than the blooming phase.

Nitrogen shortage is among the most prevalent nutritional deficiencies in cannabis in the vegetative phase. During the vegetative period, the cannabis plant requires more nitrogen than during the blooming stage. However, some producers make the error of not providing adequate nitrogen to their plants. Symptoms of a nitrogen deficit include yellowing of the leaves, beginning at the base of the plant and progressing upward.

If a cannabis plant lacks nitrogen, several things may be used as a solution. Nitrogen should be approached with prudence. Too much nitrogen may swiftly destroy a cannabis plant if applied in excess. For all nutrient shortage modifications, try adding extra nitrogen to the feeding schedule of one plant to observe how it responds. You can add additional nitrogen to other plants’ feeding schedules if it seems to assist.

Floral Magnesium shortages are more prevalent than vegetative Magnesium deficiencies, although they may occur at any time. Magnesium deficit causes interveinal yellowing on leaves, but a nitrogen deficiency causes all-over yellowing. Add additional Epsom salt to your pet’s meals to remedy a magnesium shortage.

To combat sulfur deficiency in crops, growers may use Epsom salt, which also contains sulfur. Sufficient sulfur levels might be difficult to tell apart from magnesium or nitrogen deficiency in a plant’s vegetative and blooming stages.

Hydroponic nutrient deficiencies during the flowering stage

Many different sorts of cannabis plant deficiencies are typical throughout the blooming period, in addition to those already described. There are more sorts of nutritional shortages throughout the blooming phase of a cannabis plant’s life cycle since the plant needs more nutrients at this time.

Hydroponic Cannabis
Cannabis Plants grown indoor using the hydroponic technique

It is difficult to distinguish between an iron shortage and magnesium cannabis deficiencies during blooming. Products that include both nutrients should be used more often since if one deficit is present, the other is likely to follow.

During the blooming period, potassium deficiency is also frequent. This plant is in blooming mode, which means it uses a significant amount of potassium to help the buds get larger. Leaves that have yellowed and developed a “burned” appearance around the margins indicate a potassium shortage. Potassium-rich nutrients are readily available at any gardening supply shop.

Phosphorus deficiency in cannabis plants is relatively uncommon, although it does happen. A phosphorus deficit is likely to cause brown spotting or other dark spots on the plant’s older leaves, as well as poor development and tiny new leaves. Feed the plant with a phosphorus-rich nutrition supplement to remove the spotted leaves.

Other cannabis deficiencies

You should be good to go in your gardening endeavors if you have addressed the aforementioned forms of nutritional deficits. More than that, there are a few other issues that growers should be aware of:

  • Zinc deficiency – the veins between the leaves begin to yellow
  • Younger leaves curl because of calcium deficiency.
  • Deficits in manganese are sometimes mistaken for deficiencies in phosphorus because of fading leaves and brown patches.
  • Leaves get black and glossy due to a lack of copper.

In terms of cannabis nutrients, more does not automatically equal more beneficial in the long run. Nutrients for cannabis plants, on the other hand, are costly, and using more than is necessary is akin to setting money on fire. In some instances, overfeeding a cannabis plant with nutrients might kill it more quickly than underfeeding it.

Brown spots on cannabis leaves
Photograph of cannabis leaves in bad condition. Deficiency of nutrients in cannabis plant. White spots on the leaves of the cannabis plant.

Before beginning your hydroponic garden, you will need to devote significant resources (time and money) to develop your system. To ensure that your plants thrive, you will need to ensure that your system is working correctly and that your fertilizers are of excellent quality. Having a good grasp of hydroponics will put you on the path to growing world-class cannabis that is well worth the time and effort. Take your time to learn the essentials before getting started.

Ed Rushford

Ed Rushford’s impact on cannabis growing is undeniable. Though he tends to focus primarily on 2 areas, plant training techniques and dealing with disease, pests, and other problems, he has offered many insights into how cannabis plants live and grow. That’s not to say that Ed is unfamiliar with the complete life cycle of cannabis, from seed to harvest, but he uses his widespread knowledge to hone in on the minutia and niche areas of growing cannabis. Ed’s goal is to spread knowledge and allow for everyone to become better growers. About this Author

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