Cannabis Nitrogen Deficiency: Signs, Symptoms, and Solutions

What happens to cannabis plants if they do not get enough nitrogen? Even if you’re an experienced grower, a nitrogen deficiency can be difficult to overcome if left unchecked. Thankfully, both novices and long-time home cultivators can do a few, simple things to easily mitigate any negative effects caused by low nitrogen—or ideally, prevent a deficiency altogether.

Learning how to treat a nutrient deficiency in plants and quickly identify when something’s gone amiss are two of the best ways to help ensure your home garden produces bountiful and healthy plants. Below, we address the ins and outs of nitrogen for cannabis plants. Specifically, we’ll talk about why nitrogen is so important, how to detect a problem, and how to fix the issue once it has occurred.

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The Importance of Nitrogen in Plant Growth

Nitrogen plays a key role in the cannabis plant life cycle—particularly during the vegetative stage.

Two of nitrogen’s most important functions are supporting protein synthesis and chlorophyll production. Since nitrogen is vital for nucleic acids, and these amino acids are the building blocks for protein, proper nitrogen levels help ensure the optimal growth of cannabis leaves, stems, and roots. In terms of chlorophyll, without sufficient nitrogen levels, your cannabis plants won’t be able to effectively convert sunlight into the energy needed for growth.

Nitrogen also helps with the production of compounds like cannabinoids. Without cannabinoids, a cannabis plant will not produce the effects we all know and love. Proper nitrogen levels work to enhance the overall health and vigor of your cannabis plants and promote lush, vegetative growth that sets up your garden for a robust flowering stage. 

Signs and Symptoms of Nitrogen Deficiency

Now that you know just how important nitrogen is for your marijuana plant growth, it’s time to learn how to spot nitrogen deficiency symptoms. One of the earliest and most common signs is cannabis plants yellowing from the bottom up. This occurs because nitrogen is a mobile nutrient: your plants are attempting to transport nitrogen from older leaves to upper leaves and new growth areas. 

When your plants don’t produce enough chlorophyll due to a lack of nitrogen, this will cause them to have a pale yellow or lime green pigment starting at the leaf tips. This condition, called leaf chlorosis, is a common symptom of nitrogen deficiency. You may also notice the fan leaves turning light green during flowering.

Finally, keep an eye out for stunted growth, thin and weak stems, older leaves dropping off, and a reduced bud size and quantity. All of these are signs of overall poor plant health in general, and can often be the sign of improper nitrogen levels. Other signs of a deficiency include curled or rolled leaves, slowed vegetative growth, necrotic spots on young leaves, and poor root growth.

Causes of Nitrogen Deficiency in Cannabis Plants

Nitrogen deficiency can occur for several reasons. Some of the most common causes include poor nutrient management and environmental conditions. For example, your cannabis plants will absorb and deplete the nutrients from their growing medium over time. These nutrients must be replenished; proper fertilization is key.

Improper pH levels also contribute to nitrogen deficiency. If your soil isn’t within the appropriate ranges, it can hinder the cannabis’s ability to absorb nitrogen properly. Overwatering weed plants can also lead to root rot—which in turn, impairs your plants’ ability to absorb nutrients. Other common causes of nitrogen deficiency include underwatering, cold temperatures, excessive heat, over-fertilization, and the stress that occurs alongside pests and diseases. 

The best time to treat your marijuana plant’s nitrogen deficiency is always going to be at the earliest sign of deficiency. This tends to be during the vegetative stage; this is when plants require the most nitrogen. What’s more, excess nitrogen during the flowering stage can actually hinder bud development and cause an effect referred to as “nitrogen burn” or nitrogen toxicity. Thus, it’s ideal to treat any deficiencies during the vegetative stage. 

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How to Fix Nitrogen Deficiency in Cannabis Plants

If you do start to notice the signs of nitrogen deficiency, there is some good news: In some cases, there are actions you can take right away to remedy the deficiency, and ultimately, save your plants. Increase nitrogen levels by applying a balanced, nitrogen-rich fertilizer to your plants.

Organic fertilizer options like fish emulsion tend to be effective and can act fairly quickly to reverse symptoms. From there, you will want to check and adjust your pH levels as necessary, ensuring they are in the ideal range for your medium. Finally, if you’re growing your plants in soil, try improving the quality of your medium. Supplementing your soil with organic matter such as compost or worm castings may be quite helpful.

Immediate solutions are crucial for correcting nitrogen deficiency; however, it’s also important to understand long-term strategies to help prevent any deficiency in the future. Be sure to establish a regular feeding schedule and test your soil periodically. These tactics will help address any imbalances before they become full-blown deficiencies. It’s also important to be careful with your watering, as excess water or not enough water can impact plant root health. 

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Here at Growers Choice Seeds, we understand that getting your weed seeds is just the first step: from there, you’ve got a whole growth cycle to work through. But, we want to help you every step of the way and provide the info you’ll need to produce healthy cannabis plants and generous yields.

Here are some things to keep in mind as you move forward with your cannabis cultivation:

  • Use Good Soil: Starting with high-quality soil that has been pre-mixed with a good balance of nutrients is going to be a great preventative against deficiencies in early growth stages.
  • Understand Essential Nutrients: A good understanding of primary nutrients helps ensure healthy growth. Take the time to learn about these levels during the different stages of growth.
  • Use Reliable Nutrients: Just as you wouldn’t want to buy your marijuana seeds from anyone other than Growers Choice, you should only buy your nutrients from the most trustworthy sources. Make sure to consider formulas that are cannabis-specific.
  • Maintain Optimal Environmental Conditions: It’s simple, but ensuring proper temperature, lighting, humidity, and pH levels can all help your plants use nutrients more efficiently and reduce the risk of any deficiencies.

Whether you have questions about germination, the difference between regular seeds and feminized cannabis seeds, or even highly specific inquiries, such as the best strains to grow in the winter months, we’ve got you covered. 


How long does it take to recover from low nitrogen levels in marijuana plants?

The recovery time for marijuana plants with low levels of nitrogen can vary depending on certain factors like the severity of the deficiency and the overall health of the plant. However, if addressed quickly and appropriately, cultivators may be able to see an improvement in the plant’s conditions within a week to about 10 days.

You’ll know that your plants are recovering when you notice new growth of green leaves and a more rapid growth rate overall. The previously weak stems should also start to thicken and strengthen as your plant continues to get healthy.

How can I add nitrogen to my soil quickly?

You may be wondering, “What is the fastest way to add nitrogen to soil?” There are a few fast-acting, natural ways to add nitrogen to soil quickly. These include blood meal—a powdered form of a dried waste product with a high nitrogen content, and Liquid Fish Meal, which is an organic fertilizer that’s known for its fast-acting nitrogen boost to plants.

If you’re curious to utilize additional natural ways to add nitrogen to the soil, coffee grounds, compost, and nitrogen-rich clippings are an excellent choice. Clippings, specifically, can serve as manure or mulch and will release nitrogen as they decompose. Finally, urea, a synthetic fertilizer, is high in nitrogen and acts rapidly. This chemical converts usable nitrogen when it comes into contact with the enzymes in the soil, making the chemical available fairly quickly.

What are the signs of nitrogen deficiency in marijuana plants?

Marijuana leaves will turn a yellow color in response to insufficient amounts of nitrogen. You may also notice the fan leaves on your plant transitioning to a pale, washed-out green. Any initial, vigorous growth will tend to stall throughout the vegetative stage. Finally, low nitrogen soil or medium can also cause the lower leaves to drop off entirely. 

What is the strongest hybrid strain?

Unfortunately, there are not any cannabis strains that are inherently more resistant to nitrogen deficiencies. However, some plants do tend to be more resilient in general. The overall strength of a cannabis plant towards nutrient imbalances depends on its genetics, environmental factors, and cultivation techniques. More robust and forgiving strains may be better suited to beginners worried about managing nutrient levels.

Growers Choice offers resilient, beginner-friendly autoflowering seeds like Northern Lights, Sour Amnesia, and Gorilla Glue #4, or feminized photoperiods like White Widow and Blue Dream. All of these strains are well-known for being relatively easy to grow and manage. If you’re eager to learn more about the art of cannabis cultivation, we invite you to explore our many DIY articles on a variety of topics. Good luck and happy growing! 

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