Nitrogen (N)

Marijuana Horticulture

by Jorge Cervantes

Marijuana loves nitrogen and requires high levels of it during vegetative growth but lower levels during the balance of life. Nitrogen is easily washed away and must be replaced regularly, especially during vegetative growth. Excess levels of nitrogen in harvested plants cause the dried marijuana to burn poorly.

Nitrogen regulates the cannabis plant’s ability to make proteins essential for new protoplasm in the cells. Electrically charged nitrogen allows the plant to tie proteins, hormones, chlorophyll, vitamins, and enzymes together. Nitrogen is essential for the production of amino acids, enzymes, nucleic acids, and chlorophyll and alkaloids. This important nutrient is mainly responsible. For leaf and stem growth, as well as overall size and vigor. Nitrogen is most active in young buds, shoots, and leaves. Ammonium (NH4+) is the most readily available form of nitrogen. Be careful when using too much of this form; it can burn the plants. Nitrate (NO3-) – the nitrate form of nitrogen – is much slower to assimilate than ammonium. Hydroponic fertilizers use this slower acting nitrogen compound and mix it with ammonium.

Nitrogen is the most common nutrient deficiency. The symptoms include slow growth. Lower leaves cannot produce chlorophyll and become yellow between the veins while the veins remain green. Yellowing progresses through the entire leaf, eventually causing it to die and drop off. Stems and leaves’ undersides may turn reddish purple, but this can also be a sign of a phosphorus deficiency. Nitrogen is very mobile, and it dissipates into the environment quickly. It must be added regularly to sustain fast growing gardens.

Treat deficiency by fertilizing with N or a complete N-P-K fertilizer. You should see results in four to five days. Fast acting organic sources of nitrogen include seabird guano, fish emulsion, and blood meal. Growers also report excellent results by adding bio-fertilizers to stimulate the uptake of nitrogen.

An overdose of nitrogen will cause excessively lush foliage that is soft and susceptible to stress, including insect and fungal attacks. The stems become weak and they may fold over very easily. The vascular transport tissue breaks down, and water uptake is restricted. In severe cases, leaves turn a brownish-copper color, dry, and fall off. Roots develop slowly, and they tend t darken and rot. Flowers are smaller and sparse. Ammonium toxicity is most common in acidic soils, while nitrate toxicity is more prevalent in alkaline soil.

Treat toxicity by flushing the growing medium of the affected plants with a very mild, complete fertilizer. Severe problems require that more water be flushed through the growing medium to carry away the toxic elements. Flush a minimum of three times the volume of water for the volume of the growing medium. Do not add more fertilizer tat contains nitrogen for one week so the excess nitrogen in foliage can be used. If the plants remain excessively green, cut back n the nitrogen dose.