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Nitrogen deficiency cannabis

Nitrogen Deficiency in Cannabis

Buying cannabis seeds is the first step in your exciting cultivation journey. Along the way, you may run into obstacles, but armed with the correct info, these become challenges to overcome. One of the most common of these is nitrogen deficiency in weed.

Over the following sections, we’ll show you how to identify and solve this frequently encountered setback

Let’s get to it.

a picture of nitrogen deficiency in cannabis plants
Nitrogen deficit in cannabis

What does nitrogen do for cannabis plants?

NPK ratio picture
NPK stands for potassium, phoshorous and nitrogen

All plants, including cannabis, require a host of nutrients for optimal growth. The most critical of these are the macronutrients nitrogen (N), phosphorus (P), and potassium (K). These are collectively abbreviated and displayed on fertilizers as an NPK ratio.

You’ll find a range of NPK ratios on various fertilizers. When it comes to nitrogen, nutrients for weed aimed at vegetative growth are sure to contain a significant amount of N. 

The importance of nitrogen during vegetative growth cannot be understated, as it facilitates several essential plant functions. A nitrogen deficiency in cannabis prevents the following processes from being carried out optimally:

  • Plants use nitrogen to produce the green pigment in their leaves called chlorophyll. This compound is vital for photosynthesis. This process uses light to convert water and carbon dioxide into glucose. 

These photosynthesized sugars provide energy and go towards the production of cellulose and starch.

  • Plant proteins are created using amino acid building blocks. These proteins, in turn, form not only the structural components of crops but also enzymes and hormones essential for healthy growth.
  • Nitrogen is also a key component in producing nucleic acids such as DNA which are necessary for growth and reproduction. Without these acids, plants may experience a wide range of issues.

Now that you understand this mineral nutrient’s importance, let’s move on. First, we’ll look at identifying the signs of a lack of N before learning what steps to take to solve the problem.

How to identify nitrogen deficiency on weed plants

nitrogen deficiency in cannabis chart
The signs of nitrogen deficiency in cannabis

With this nutrient serving many roles, a shortage has the potential to cause lots of issues.

Before looking at the symptoms of nitrogen deficiency in weed, it’s essential to understand its properties. This substance is a mobile nutrient, so plants can move it to the areas it needs most.

A nitrogen deficiency poses the most significant threat during veg and is rarely a cause for concern in the flowering stage. Plant requirements change as efforts move toward bud production, and demand for N drops significantly.

nitrogen deficiency during veg
During vegetative stage, nitrogen deficit shows as yellowing leaves starting from the tips

Fertilizers designed for the flowering phase usually contain more P and K, as these are in higher demand during bloom. Some formulations for the late flowering period might not have any nitrogen whatsoever.

nitrogen deficiency during flowering stage
Here is how the deficit of nitrogen looks in the flowering stage

Fresh new foliage toward the canopy is rarely lacking in N. As a result, older, larger leaves toward the bottom of the plant will be the ones to display symptoms first. This behavior lets you rectify the problem before it gets too bad.

lower leaves turn yellow and brown
As nitrogen deficiency progresses, lower leaves start looking yellow and brown, they may be crispy

It’s natural for older foliage to yellow off and wilt in the weeks leading up to harvest, especially after flushing. Many growers consider it a positive sign that their crops aren’t retaining high amounts of nutes, resulting in tastier buds.

Unless you observe progressive signs of nitrogen deficiency during early flowering, don’t stress over minor yellowing on lower leaves. These have performed their function and are no longer critical as the plants bloom.

With the above knowledge in hand, here’s what you’ll need to keep an eye out for during cultivation:

  • Yellow Leaves: A cannabis nitrogen deficiency causes your crops to prioritize delivery of what little they have to newer growth. Older foliage is left without N and is unable to produce chlorophyll. 

Leaves turn a pale lime green before displaying yellow discoloration at the tips.

yellow cannabis leaves show the signs of nitrogen deficiency
Yellow foliage is the major sign of N deficiency as the leaves are unable to produce chlorophyl.
  • Progressive Discoloration: Unlike leaf septoria, with its yellow spots, N deficiency is progressive. Entire fan leaves are drained of their vibrant green, leading to the following symptom. Catch the signs early, and nitrogen deficiency in weed is much easier to deal with.
discoloration of bottom leaves due to the lack of nitrogen
Yellowing is usually starting from the bottom leaves while younger leaves remain green.
  • Wilting Leaves: Once the discolored foliage is robbed of all its chlorophyll, it begins to wilt, die, and fall from the plant.
wilting cannabis leaves
At the late stage of a nitrogen deficit, cannabis leaves begin to wilt and die, as shown at the picture above
  • Stunted growth: A continuing lack of nitrogen results in the entire plant growing much slower than it should. New leaves come in small and wispy, and progress crawls.
  • Clawing: Weakened leaves curl in on themselves and take on a claw-like appearance. Remember that this symptom may have other causes, such as nitrogen toxicity, nutrient burn, pests, or root rot.
older cannabis leaves are clawning
Older leaves start clawning and curling down

Now that you know what to look for, let’s discover how to fix nitrogen deficiency in weed plants.

How to fix nitrogen deficiency in weed plants

A shortage of nitrogen is one of the most common cannabis deficiencies. Use these tips to treat the problem and get your crops back on track for a healthy harvest.

 nitrogen deficiency in cannabis
Nitrogen deficiency in Royal Gorilla cannabis strain

Check pH levels 

One of the most common mistakes beginner growers make is failing to monitor their pH levels. If the medium you’re using doesn’t have the right balance, your plants can’t absorb the required nutrients effectively.

Regularly check your medium’s pH, maintaining it within the optimal range of 5.5–6.5. An incorrectly balanced medium is one of the causes of nitrogen deficiency in cannabis plants.

Ideal PH level for weed
The schema of PH levels for cannabis

Adjust nutrients

If the symptoms persist, it’s time to adjust your feeding solution. One of the next leading causes of N deficiency is using old, unsuitable soil leached of all nutrition. 

Short of repotting your plants, the next best course of action is to increase nutrient amounts.

Most fertilizers for weed aimed at the vegetative stage contain plenty of nitrogen. Follow the manufacturer’s instructions, and don’t go overboard. Adjust your dose gradually to avoid causing toxicity or nutrient lockout.

Prune affected leaves

Pruning is cutting back foliage that’s already yellowed off reduces your plants’ overall requirements. With less demand, crops have a chance to recover using the tips mentioned earlier.

Action these three guidelines, and you should start seeing your plants recover within a week or two. Nitrogen deficiency in cannabis only becomes a significant setback if it’s allowed to develop unchecked.

As with many obstacles to cultivation, prevention is better than cure. You could avoid most problems like this by using high-quality cannabis seeds and materials and remaining attentive to your plants’ needs.

It’s also important to reiterate that nitrogen deficiency during flowering, especially toward the end of this period, is nothing to worry about. It’s perfectly natural to see some leaves yellow off and wilt as energy shifts toward plumping up those juicy buds.

Nitrogen toxicity in cannabis: More is not better

Sometimes, growers identify a marijuana nitrogen deficiency, begin to panic, and in their attempt to solve the problem, overcorrect. With high N levels in most potting media and fertilizers, overdosing your crops is easily done.

Provide too much N, and you’ll end up with nitrogen toxicity. An excess of N results in excessive overgrowth of leaves, weakened stems, and a diminished rate of photosynthesis

nitrogen toxicity in cannabis plants: leaves edges are curling up
With too much nitrogen, you may see cannabis leaves are curling up

Ultimately, yields get negatively impacted, and it can also result in the production of malformed, low-quality flowers.

Plants affected by this issue display the following symptoms:

  • Discoloration: Foliage begins to turn an unusually dark shade of green. Depending on the strain, leaves may look and feel glossy.
  • Leaves edges are curling up: Leaf tips turn up and in, creating the appearance of a curling. This curling of leaves could also be a case of N deficiency, so be careful not to misdiagnose.
  • Yellowing leaves: As with a shortage of nitrogen, too much can cause yellowing and browning of leaves that subsequently wilt and fall off. This symptom is also found in N deficient plants and may confuse growers unfamiliar with the problem.
  • Nutrient burn: Elevated N levels in the foliage may cause nutrient burn along its edges. Of course, this problem may be caused by an excess of minerals other than nitrogen.
  • Stressed crops: Plants absorb more water as a survival response. If that water contains toxic levels of nitrogen, the problem could worsen.
  • Spotting: Leaves begin to display yellow or brown spotting, dying off soon after. Be wary of misidentifying this symptom, as it may result from various other issues.

Common symptoms of nitrogen toxicity are sometimes mistaken for a deficiency, leading to growers compounding the issue. The key is to remain calm, try to confirm the problem, and take appropriate action incrementally.

Be attentive, keep calm, and grow weed

A weed plant nitrogen deficiency is alarming for any home grower, but it’s not the end of your crops. Regularly monitor your plants, maintain optimal pH levels, and use a nutrient-rich medium, soil or hydroponics; you’ll likely avoid the issue entirely.

If you see signs of a nitrogen deficiency, keep calm and implement our simple tips to return your crops to perfect health.

If you’re new to growing and reading up on the subject, you’re in the right place. Check out our other articles, from the best germination methods to when to harvest cannabis.

Once you’ve done your research, why not head to our store, pick up a pack of high-quality seeds and start your adventure? Some of the best strains on the planet are waiting to be sown and cared for by you.

AUTHORED BY: Douglas Kester Mr. Kester came to i49 with a wealth of experience. He’s worked in the cannabis industry for more than ten years. As a growing expert at i49, Doudlas finds it hard to choose a favorite strain. Instead, he regards each one as unique and full of potential. Douglas finds it rewarding to experiment with specific cultivars and cross-breed to discover a new one. He strongly believes in sharing the benefits of marijuana with as many people as possible to avoid any misconceptions about the herb. Mr. Kester creatively produces information based on what he’s learned and his experience obtained by implementing what he knows. i49 is proud to have Douglas as part of the team.

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