Nitrogen Deficiency and Toxicity In Weed

Vegetative marijuana loves nitrogen and will absorb it quite quickly. More nitrogen is needed by the plant during it’s vegetative stage, and a balanced amount is required throughout the plants life cycle. Nitrogen is easily washed away with water and must be applied regularly. Too much nitrogen in a harvested plant will cause it to burn poorly. Let’s figure out how to identify a nitrogen deficiency and toxicity in weed.

Nitrogen regulates a marijuana plants ability to build proteins essential for the creation of new cells and is essential for production of chlorophyll, amino acids, enzymes, alkaloids and nucleic acid. It’s major purpose is for leaf and stem growth as well as the plants overall size and vigor.

Nitrogen Deficiency in Cannabis Plant

Nitrogen is the most common nutrient deficiency when growing marijuana. Symptoms of this deficiency are slower growth and lower older leaves start to turn yellow because they can’t produce chlorophyll. Nitrogen is very mobile and dissipates quickly into the environment,  and it must be added regularly to sustain fast growth.

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Nitrogen Deficiency In Weed

illustration of nitrogen deficiency in cannabis leaf

Progression of symptoms

  • Older leaves yellow between veins then entirely
  • More leaves yellow, and severely affected ones fall off
  • Stems and leaf veins may turn a reddish-purple
  • All leaves begin to yellow and more leaves begin to drop
  • Interveinal Chlorosis (the yellowing of spaces between veins)
  • Signs of a marijuana nitrogen deficiency begin on lower leaves and move up the plant.

Treating a Marijuana Nitrogen Deficiency

To fix a Nitrogen deficiency, fertilize your plant with more nitrogen or a full NPK fertilizer like Reefertilizer Grow wich has plenty of Nitrogen. The plant should begin to improve in 4-5 days. Some leaves may not return to a green colour.

Nitrogen Toxicity In Cannabis

Progression of symptoms

  • Leaves start turning a darker green than usual.
  • Leaf tips may bend sharply downwards, a symptom known as “the Claw.”
  • The affected leaves may appear shiny or feel unusually smooth.
  • As the condition advances, you might notice yellowing of the leaves.
  • The plant’s growth may slow down, particularly noticeable in the buds during the flowering stage.
  • Over time, the dark green leaves can begin to yellow, develop brown spots, and eventually die off.
  • In severe cases, the stems of the plant may weaken, and the leaves can start to dry out, turning a brownish-copper color before falling off.

Treating a Marijuana Nitrogen Toxicity

Nitrogen toxicity causes the foliage to become delicate and dark green in colour, and is very susceptible to damage from bugs, and infection. Water uptake is slow, stems weaken and if it’s severe, leaves will begin to dry out, turn a brown copper and start to fall off.
Toxicity can be treated by flushing the soil with a diluted full NPK fertilizer.

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