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Fixing Common Cannabis Deficiencies

How to identify and fix cannabis deficiencies

Is your marijuana plant dying, and you’re not sure why? You could have one of the many cannabis deficiencies. 

Weed plants need three macronutrients and about another 20 micronutrients to grow into a healthy, high-yielding, potent harvest. When there’s an imbalance somewhere, your crop will have a cannabis nutrient deficiency. 

If you think this could be your issue, continue reading to find out everything you need to know about cannabis deficiencies, how to identify, treat and prevent them, and how to maintain a healthy crop. 

What are cannabis deficiencies?

A cannabis deficiency is when your weed plant doesn’t have enough nutrients and begins to die. 

A healthy marijuana plant has green leaves, sturdy stems and produces resin-filled buds by flowering time. 

If you see discoloration, stunted growth, or deformed leaves or stems, it’s likely your crop has a cannabis deficiency. The exact symptoms will help you determine which element is deficient. 


Cannabis deficiency burnt leaves

Nutrients and pH levels for cannabis

What causes cannabis nutrient deficiencies? One reason this could be happening to your weed plants is from a pH imbalance. 

Ideally, you want your growing medium at a pH range of 5.8 to 6.5. Anything out of this range on either side, the roots can’t absorb nutrients well, and your plant will have a cannabis deficiency

If the pH is out of whack, you need to flush the marijuana plant with distilled water. Add a balanced fertilizer and keep up a regular cannabis feeding schedule

When the pH is within the slightly acidic range, your marijuana crop will begin to absorb cannabis nutrients correctly again. 

You should trim any leaves or branches that look affected by the cannabis deficiency, as they won’t come back to life. Your focus at this point is to save the remaining parts and ensure healthy growth from here on out. 

Cannabis deficiencies and water supply

Tap water can contain other minerals, which can cause cannabis deficiencies. The excess of elements in the water can block the nutrients from being absorbed, especially if any salts are present. 

Before using your tap water for your marijuana plants, make sure to test it. Depending on the results, you might need to change your fertilizer or purify it prior to use. 

If you’re experiencing a cannabis nutrient deficiency, the problem could stem from your water. For best results, use distilled or deionized water for your weed crops. 


cannabis leaf chart

Cannabis macronutrients and micronutrients

We’ve talked so much about cannabis nutrient deficiencies; you’re probably wondering what elements weed plants need. You can break them down into two categories; macronutrients and micronutrients. 

Macronutrients are the main elements marijuana needs to survive without a cannabis deficiency. Those are nitrogen, potassium, and phosphorus. 

The micronutrients are the other minerals required for a healthy marijuana plant, but the crops only need a trace amount. The micronutrients ensure that cellular biology is functioning correctly. Those include magnesium, calcium, boron, copper, iron, manganese, molybdenum, silicon, sulfur, and zinc. 

How to identify and treat nutrient deficiencies

Cannabis deficiencies present themselves in general as discoloration, deformed leaves, or stunted growth. You can take a closer look at each element to understand precisely what’s lacking. 

Let’s look at the most common symptoms of each type of cannabis nutrient deficiency. 

Nitrogen deficiency

Nitrogen is one of the macronutrients, so a cannabis nutrient deficiency of this mineral is serious. You can identify a nitrogen deficiency in a weed plant by its leaves. 

The leaves will turn yellow from tip to stem, lose their luster, and be much smaller than usual. It’s expected that the leaves will curl and drop. A nitrogen deficiency in weed plants will cause premature flowering and a lower overall yield. 

Phosphorus deficiency

Phosphorus is another central element for weed plants. A phosphorus cannabis nutrient deficiency will show as bluish-green leaves that can turn a dark copper color. 

A phosphorus deficiency in cannabis will be shorter and smaller than average. The crop will be weak at fighting diseases, pathogens, or pests. With time, the leaves will droop, curl, and wither. 

Potassium deficiency

Another essential element for growing marijuana plants is potassium. A potassium cannabis nutrient deficiency presents leaf margins and tips, turning a rust color and the rest yellow. 

The stems of the plant with a cannabis potassium deficiency will become weak and won’t support the weight of the leaves. The ends of the leaves will curl and almost look burnt. 

Magnesium deficiency

Although magnesium is a micronutrient, it’s still vital to the health of weed plants. When you’re experiencing a magnesium cannabis nutrient deficiency, the overall crop will look sick. 

A magnesium deficiency in weed plants will show as interveinal yellowing, along with brown spots on weed leaves. They’ll be dry, brittle, and start to curl. 

Calcium deficiency

A plant with a calcium cannabis nutrient deficiency will be stunted and flower slower than usual. There will be irregular yellowish-brown spots on weed leaves

The leaf shape will be contorted and curl downward. If the crop makes it to harvest, the yield will be small. 

Boron deficiency

A boron cannabis nutrient deficiency will show in the weed plant’s stems, tips, and roots. The stems will be weak and take on a rust color. The ends of the leaves will start to curl and turn brown. 

There will be yellowing between the leaf veins. The blades will thicken and become brittle. 

Copper deficiency

Copper is another micronutrient for weed plants. The leaves of a crop with a copper cannabis deficiency will be a very dark green, almost greyish. 

Younger leaves with a copper deficiency in cannabis will wilt and curl. The plant will experience stunted growth and have a decreased yield.


Cal-mag marijuana deficiencies

Iron deficiency 

A crop with an iron cannabis nutrient deficiency will have leaves with interveinal chlorosis starting at the end closest to the stem of the plant. The rate of growth will be slowed. 

If a cannabis iron deficiency is left untreated, the tips of the leaves will begin to turn brown, drop, and wilt. 

Manganese deficiency

A plant with a cannabis deficiency of manganese will have yellow leaves and dead brown spots. Eventually, the whole leaf will become pale and start falling off the stems. 

A specific characteristic of a cannabis manganese deficiency is that the margins are rich green while the surrounding parts are yellow. The signs will first show up in new leaves. 

Molybdenum deficiency

A molybdenum deficiency in cannabis shows as dropping and dry leaves. There will be yellowing starting from the tip that will start to fall downward. 

Silicon deficiency

A plant with a silicon cannabis nutrient deficiency is rare if you’re using natural soil, as there’s an abundance of it in soil. It’s more common when you use a soilless growing medium. 

The weed crop with a silicon deficiency will have weak branches and steam. The plant will be more vulnerable to pests. 

Sulfur deficiency

A crop with a sulfur cannabis deficiency will have young lime-green leaves. The light green color will begin to turn yellow, and the size of the leaves will be small. 

The stem of sulfur deficiency in cannabis plants will have long purple streaks and turn woody. The leaves will hook downward and have a burnt look. 

Zinc deficiency

A zinc cannabis nutrient deficiency will show signs of leaf discoloration. Young leaves will be yellow, fragile, and wrinkle. Older leaves will also begin to yellow, and the tips will curl and appear burnt. 

The marijuana plant will have stunted growth, tiny buds, and an overall low yield. 

How to prevent cannabis nutrient deficiencies and keep your plants healthy

Marijuana plants are a little finicky while growing. The best way to prevent a cannabis nutrient deficiency is to ensure the environment and feeding schedule are all in sync. 


cannabis deficiencies


These are our tips on how to prevent a cannabis nutrient deficiency:

  • Buy high-quality weed seeds
  • Use purified water and water often
  • Buy a well-balanced nutrient supplement or make your own organic homemade fertilizer
  • Don’t overfeed
  • Use quality soil 
  • Provide sufficient light and ventilation 

The most crucial factor in cultivating a healthy, high-yielding, potent marijuana plant resistant to a cannabis nutrient deficiency is buying high-quality weed seeds. You can find a large selection at i49 Genetics. 

Final points on cannabis deficiencies

Any problem when growing marijuana is a headache, and a cannabis nutrient deficiency is never fun. Providing a well-balanced fertilizer is the best way to ensure your crops are getting the correct nutrients. 

Weed plants need nitrogen, potassium, and phosphorus to mature into healthy crops. The micronutrients include magnesium, calcium, boron, copper, iron, manganese, molybdenum, silicon, sulfur, and zinc. 

Depending on which element is deficient, the marijuana crop will show specific signs of cannabis nutrient deficiencies

Now you know about cannabis deficiencies and what to look for while growing. Buy marijuana seeds today and start cultivating your own plants in just a few days! Purchase the i49 Genetics nutrients to ensure a healthy harvest.