Deficiencies and excesses of nitrogen

In the world of agriculture and plant growing, nitrogen is an essential element that plays an important role in the development and health of plants. Today we invite you to discover the complexities and benefits of nitrogen in the growing process, the different types of nitrogen that can be found in fertilizers, its impact on plant growth, and other fundamental aspects that make it an essential element for crop success.

Without a doubt, nitrogen is one of the most important elements in cannabis cultivation, which promotes healthy and vigorous growth and which, of course, cannot be missing from any balanced diet for plants. We tell you everything below!

 Nitrogen is a fundamental macronutrient for correct development during the vegetative or growth phase
Nitrogen is a fundamental macronutrient for correct development during the vegetative or growth phase

Nitrogen (N) in cannabis cultivation

Nitrogen as a nutrient is a very important mobile element that interacts directly in the development of marijuana plants during all their life phases. Depending on the life stage of the plants, they will have a greater or lesser demand for this nutrient.

Nitrogen regulates the capacity of marijuana plants to create proteins, amino acids, enzymes, chlorophyll, alkaloids, and nucleic acids, being mainly responsible for the growth of the stem, leaves, branches, and vigor in general.

Nitrogen can be found in different formats: organic, ammoniacal, and nitric. The basic difference between these formats is the speed of nitrogen absorption by the plant, with the ammoniacal format being the one with the fastest absorption and consequently, the one that can more easily produce an excess of this nutrient.

On the contrary, nitrogen in the form of nitrate is also easily absorbed by the plant, although it does so more slowly. It is for this reason that in liquid fertilizer bottles, we will find nitrogen mixed in both formats to balance the absorption of nitrogen by plants without them suffering from an excess or lack of this macronutrient.

 The nitrogen cycle includes a series of processes
The nitrogen cycle includes a series of processes

If the plants' demand is greater than the nitrogen they have at their disposal, they will suffer a deficiency; On the other hand, if the levels of this element are higher than what the plant needs, it will suffer from overfertilization.

We can find fertilizers in two formats such as mineral or organic. The mineral format has a faster absorption by plants since it does not have to be previously processed by the microbial life that lives in symbiosis with the soil to be absorbed by plants. Likewise, as we have already mentioned, you may find nitrogen-rich fertilizers in both liquid and solid formats.

An optimal level of nitrogen in plants will result in:

  • Vegetative vigor
  • Lush green color in the leaves due to the production of chlorophyll
  • Increase in the number of plant leaves, stem span, fruits, and seeds
  • Greater resistance of plants against fungi
  • Greater resistance of plants against insects
  • Greater resistance to frost and hail


From 10.55€ 14.11€

View product

From 8.45€ 11.30€

View product

Nitrogen deficiency in marijuana plants

When cannabis plants do not have balanced nutrition and a lack of this element occurs, abnormalities arise in their development that are visible through the morphology of the plant, which we call deficiencies.

  • Plant growth is much slower.
  • The leaves turn yellow gradually, starting at the bottom of the plant. Chlorosis begins at the tips and becomes lighter towards the center of the leaf.
  • Plants have fewer defenses against pests, diseases, and stress.
  • Flowering and seed production are seriously reduced.
  • Massive defoliation after advanced chlorosis.
  • The deficiency progresses from the bottom up, affecting the youngest leaves last.

To quickly solve the problem, a fertilizer rich in nitrogen in liquid form should be added to the nutrient solution so that the plants can recover their optimal levels of this nutrient a few days after watering.

It should be noted that when the plants already have these deficiencies, their capacity to produce will have already been reduced, so it is important to maintain a balanced diet throughout the crop to obtain optimal quality and production.

 Healthy cannabis plants should show leaves without any type of yellowing, which would indicate some type of deficiency (Image: jcomp)
Healthy cannabis plants should show leaves without any type of yellowing, which would indicate some type of deficiency (Image: jcomp)

Excess Nitrogen in marijuana plants

On the contrary, excess nitrogen in marijuana plants also takes its toll by reducing their production and quality of flowers. These excesses can be recognized by observing the following symptoms:

  • Excess foliage on the plant.
  • Weak stems.
  • Delay in the ripening of fruits, making them less sweet.
  • Claw-shaped leaves facing the ground.
  • Poor combustion of the buds
  • Very intense green on the leaves
  • Poor resistance to pests in general.

To solve this, we will carry out a root wash using three times as much water as the capacity of the pot along with low EC levels. We must measure the output EC to know how saturated the substrate is with salts and in extreme cases we will not stop washing until the nutrient levels of the substrate are the same as the water we use to wash.

For these processes, we can easily use salt-breaking products to help leach the substrate for faster recovery, like most enzymes.

 Nitrogen is a mobile nutrient: since it is needed to create new shoots, it will be taken from the oldest leaves of the plant if it is not found in the soil
Nitrogen is a mobile nutrient: since it is needed to create new shoots, it will be taken from the oldest leaves of the plant if it is not found in the soil

How cannabis recovers from excess nitrogen

Cannabis is a plant that, as we have already mentioned, is capable of morphologically showing its vital state so that it will be easy to know the state of our plants through its leaves, color, shape, etc.

In the case of having suffered slight overfertilization or in the opposite case in which there has been a lack of the same element, the cannabis plant will always take a few days to recover. The speed of recovery will always depend on the degree of deficiency or excess that the plant may have, so rapid detection will always help facilitate their recovery in a shorter time.

Depending on the substrate along with the fertilizers used, the plants may recover more or less quickly. In hydroponic growing systems, the speed of plant recovery will be much faster than in soil cultivation with organic fertilizers. As we have already mentioned at the beginning of the post, depending on the format in which the nutrients are presented, they will be faster or slower absorbed.

In the growth phase and in the case of a small overfertilization when there is an excess of this element, we will proceed to reduce or eliminate the growth fertilizer during a few waterings.

In the case of using additives for marijuana, we can continue adding them in the usual way since they do not contain food, only elements that will allow the plant to metabolize the excess food, creating more leaves, and branches ... in short, that grow and use up the nutrients they contain.

 Progress of nitrogen deficiency
Progress of nitrogen deficiency

During the flowering phase, if we suffer from overfertilization we must act according to the crop week we are in. If it happens during the first two weeks after the change of photoperiod, we will act in the same way as if we were growing, since the plants will still grow almost until the 3rd week, when the buds begin to show.

On the contrary, if we are already in flowering, nitrogen excesses are not usually so common, but if there are then we must remove the base fertilizer, to continue fertilizing only with a PK supplement which does not contain added nitrogen. In this way, the plants can continue feeding to create buds depending on the phase they are in and at the same time eliminate excess nitrogen. In the case of more pronounced overfertilization, we can previously carry out a root wash to clean the substrate a little of excess nutrients and then irrigate with the appropriate doses of PK until indicated on the product label.

Happy harvest!

The articles published by Alchimiaweb, S.L. are reserved for adult clients only. We would like to remind our customers that cannabis seeds are not listed in the European Community catalogue. They are products intended for genetic conservation and collecting, in no case for cultivation. In some countries it is strictly forbidden to germinate cannabis seeds, other than those authorised by the European Union. We recommend our customers not to infringe the law in any way, we are not responsible for their use.

Comments in “Deficiencies and excesses of nitrogen” (5)


Darrin Fulghum 2018-10-07
Can harvested flowers contain too much nitrates to affect it or is it more likely poor drying/curing ??? My grow partner used a higher than normal nitrogen fertilizer this year. Now after harvest he says the buds are full of nitrates and when smoking them we are giving ourselves nitrate poisoning.. Is any of this true??? Am I in danger?? If true can it be removed??

Alchimia Staff

Tim Alchimia 2018-10-08
Hi, I'm not sure about nitrate poisoning, I've never heard of that before, I know that weed that has too much nitrogen fertiliser at harvest time can be very harsh and unpleasant to smoke, because of high levels of chlorophyll caused by too much fertiliser. However I don't think the flowers themselves will have a high nitrate content, I'd be really surprised if you were actually poisoning yourselves. If you want to be sure about your health then maybe find a lab that can test the flowers for nitrate content. The best thing to do would be to leave the weed to cure properly over a few months, which ought to reduce the levels of chlorophyll and other harsh tasting compounds. If that doesn't work then personally I'd make hash with the flowers, by separating the resin from the plant material you can sidestep that awful flavour caused by too much nitrogen fertiliser. Next time you grow, remember that more fertiliser does not necessarily mean more buds, and if you want really tasty weed, just use much less fertiliser than the recommended amount. Good luck, I hope it ends up tasting better.


H.M. Hari 2017-11-30
I have small kitchen garden and have been facing sever problem. Bottle gourd and ridge plants which quite look quite healthy setting female flowers in very large numbers but not a single fruit is maturing. All are turning brown and subsequently falling off. What is the reason and what should I do in order to retain fruits.

Alchimia Staff

Tim Alchimia 2017-11-30
Hi, thanks for your question. Sorry to hear about your plant problems. Are you saying the flowers turn brown and fall off before fruiting? It sounds to me like the female flowers aren't being pollinated. Are you seeing any male flowers appear? Cucurbit male flowers are usually on a longer, slender upright stalk. An easy solution to ensure fecundation would be to hand-pollinate the plants yourself using a small brush or cotton bud to apply the male pollen to the stigma of the female flowers. It could be that your garden isn't being visited by pollinating insects, so a good idea to encourage them is to plant a variety of flowers that will attract bees, butterflies etc. Al the best!


Janet eschmamm 2017-07-18
What can I do for my plants they have way to much nitrogen wilting leaves turned brown and are curling. They are way to big to flush the roots.. Put way to much cow shit water to them. They were very healthy plants . I don't want to lose them. What can I do

Alchimia Staff

Dani Alchimia 2017-07-19
Hi Janet, You can try to water your plants with water+enzymes, they'll help to break down accumulations of nutrients. I know some people plant other vegetables to "clean" the soil from excess nutrients, like roses,corn, lettuce, tomatoes, squash, cucumbers, mustard and cabbage (corn and mustard are fast to start). Still, you should really flush them with enzymes no matter how big they are, simply use more water!! I've also found some poeple add wood chips to the soil to lock up excess nitrogen. Hope it helped!


Janet eschmamm 2017-07-18
My husband put way to much cow shit water in my plants and in3 days they went from strong green healthy georgous plants to Brown wilty sad looking plants. They are way to big to flush the roots. Please help me makes me want to cry when I look at them.


ronald gard 2016-07-13
Too much steer manure was put at the bottom of my plants they are suffering from too much nitrogen they have been in the ground for a month can anything be added to the soil to reduce the nitrogen

Alchimia Staff

Dani Alchimia 2016-07-14
Hi Ronald, You can use other plants like squash, cabbage, broccoli and corn which use lots of nitrogen to grow and act as sponges of this element. Using dry mulch also helps to reduce nitrogen. You can also add wood chips to the soil. Hope it helped!

Do you want to give your opinion on deficiencies-excesses-nitrogen or ask a question about this product?

To be able to post your comments you must be identified as a user. Identify yourself or sign up as a user.

About this Cannabis Blog

This is the official blog of Alchimia Grow Shop. This blog is intended exclusively for the use of adults over the age of 18 years.

To buy equipment for growing cannabis at home you can consult our catalogue of cannabis seeds, grow shop and paraphernalia

Subscribe to the blog

Do you want to receive all the latest developments, news and curiosities from the world of cultivation?

(+34) 972 527 248
(+34) 972 527 248
keyboard_arrow_up Chat on Telegram