Is it common for marijuana plants?
A Nitrogen (N) deficiency is the most common deficiency that occurs in cannabis plants.
Pale green leaves are the first appearance of this deficiency. After this the cannabis leaves turn yellow and die. Meanwhile the nitrogen travels to support the new growth. In the end the lower leaves turn yellow and die from the leaf tips inward. The deficiency keeps traveling up so only the new growth is green. Smaller leaves, sparse profile and slow growth are other signs of this deficiency. Another sign is the petioles and stems turn a purple/red tinge.
An overdose of nitrogen can cause a dark green growth. This dark green growth is more susceptible to disease and insects. The lack of flexibility causes the stalks to become brittle and they break. This is an effect of the overdose on Nitrogen.
Nitrogen is very mobile. It can travel anywhere. Nitrogen travels to the new growth so the deficiency usually starts at the lower parts of the marijuana plant.
Role in nutrition of the marijuana plant
It is directly responsible for the production of amino acids and chlorophyll. Nitrogen is also an essential element to photosynthesis. Nitrogen plays an important role in the growth of the marijuana plant; it is an essential element of tissue. Without the nitrogen the growth will quickly stop.
Quickly available to the roots are nitrates, NO3 but also any other water-soluble nitrogen. You can also use insoluble nitrogen, like urea. This type of nitrogen has to been broken down by microbes in the soil. After that the roots can absorb it. Once nitrogen-deficient plants have been fertilized, they absorb N as soon as it becomes available. Then the marijuana plants turn from pale looking into a healthy-looking green. Usually this takes about a week, the leaves that were affected the most will not recover.
On all fertilizers packages a three number set is listed. It lists N-P-K (always in this order). You can use a water-soluble fertilizer that has a higher level of N (than P and K) for solving the nitrogen deficiencies. This solves the deficiency very quickly. In this category you find most hydro vegetative formulas. To act fast, use calcium nitrate (CaNO3). This is water-soluble and can be used in the water/nutrient solution and as foliar fertilizer. What also acts quickly is fish emulsion (5-1-1) high-Nitrogen bat, urine, or seabird guano. Some high-nitrogen fertilizers supply nitrogen fairly quickly but it is released over the growing season. You can use manure, alfalfa, feather meal, fish meal and cottonseed meal.
Discussion in general
During the vegetative growth stage, high amounts of nitrogen reduce the marijuana plant’s yield enormously. From vascular breakdowns in the plants the up-take of water slows. Issues concerning N occur in the entire growth cycle. During the vegetative growth stage the marijuana plants should not suffer of N deficiency. What also causes N problems is over-fertilization.
Towards flowering tapering off the use of nitrogen promotes flowering instead of vegetaqtivee growth. Still it is necessary to have a small amount of nitrogen. The manufacturing of amino acids requires nitrogen. Nitrogen is an ingredient for the manufacturing. The flower growth is supported by the amino acids. Also amino acids support the P and K utilization. There are “Bloom Boosters” that have a 0-50-30 N-P-K ratio. The numbers of P and K are quite impressive. But if you use this fertilizer too early, it will cause the flowers to grow smaller than they should be. Enough residual N must be available for the marijuiana plants. Otherwise the marijuana plant doesn’t get the most out of the fertilizer.
Many marijuana plants show a N deficiency in the middle/end of the flowering stage. The plants use the stored nutrients from the cannabis leaves. They drop of their oldest and bottom fan leaves. Gradually switch to bloom nutrients (unless it contains some N), to prevent an extreme case of N deficiency.
After a week the marijuana plants switch over to flowering growth. In this phase the plants need more of P and K. Still N is required. Because N is still required, use 1 part each bloom and vegetative during the first week of the flowering stage. During the second week, use 2 parts bloom and 1 vegetative. Use 3 parts bloom and 1 veg, during the third week. After the third week use only bloom formula, although the marijuana plants still need N in the flowering process. When the marijuana plants are growing vegetatively they don’t need the amount of N they needed before. If you gradually move from grow nutrients, the marijuana plants will still receive enough N. At least enough Nitrogen to last through the flowering process.