Cannabis nutrients

Cannabis nutrients

Cannabis nutrients are divided into two types, macro and micro nutrients, although both are necessary to get a good marijuana plant

Cannabis nutrients are those elements of the periodic table that our marijuana plants need to provide us with the best version of themselves. Although both macro nutrients and micro nutrients are necessary to achieve a good marijuana plant, macro nutrients may be somewhat more important since without them the plant could not live.

In fact, there is an international fertilizer brand that many farmers around the world call triple 15. Why? Because they are blue balls that contain 15% nitrogen (N), 15% phosphorus (P) and 15% potassium (K), which are the 3 macro nutrients. It is important to explain that there is no plant on planet Earth capable of assimilating 15% of a nutrient, either macro or micro nutrient.

The cultivation fields of many countries have been devastated by the continued use of this triple 15 that kills microorganisms that live in the soil and how important they are for any type of plant in general, and for the cannabis plant in particular. In our article “Native microorganisms for your cannabis plants” we explain precisely the role of microorganisms in the good cultivation of any plant species, including marijuana.

Although cannabis nutrients are of the utmost importance to achieve a marijuana plant that is optimal, of the best quality, it is not easy to know precisely the amount of each nutrient that we must provide to our plants. The amount depends on several factors such as EC (electrical conductivity) of the water, the pH, the cannabis variety, the environmental temperature, the type of substrate and more. On the other hand, it should also be understood that some nutrients such as nitrogen (N), should be used in greater amounts during the vegetative growth phase. And phosphorus (P) and potassium (K) must be used in greater quantity during the flowering phase.

What would happen if during the flowering phase we gave our plants the same amount of nitrogen (N) that we gave them during the vegetative growth phase? We would get plants with less flowers and the flowers would be of worse quality and smaller. What would happen if we didn’t provide our cannabis plants with enough phosphorus (P) and potassium (K) during the flowering phase. We would obtain smaller flowers with little resin, which is where THC and CBD are located, in addition to all cannabis terpenes, as explained in our article “Terpenes in cannabis“. When we supply nutrients in our crop it is possible to fall into one of these two errors: give the plants too much or give them too little. Both errors are harmful to our plants, but it is worse to give them too much than to give them little. When we give them little the solution is to increase the amount and / or frequency of subscriber. But when we have poisoned our plants due to excess of fertilizers it is more complicated to return to normal. But it is important to know that cannabis nutrients allow us greater margin of error when they are organic. Those who are chemical leave almost no room for error before killing the plant.

Cannabinoids in cannabis

THCV. The most hallucinogen cannabis cannabinoids

Deficiencies Vs Excesses of cannabis nutrients

Both the deficiencies and the excess of nutrients in cannabis plants will prevent us from getting marijuana plants of the best quality. Therefore, we must try to prevent plants from developing deficiencies or excesses. Let’s start by determining what the shortcomings are and what the excesses are.

What are the shortcomings? They are the lack of some nutrient. To avoid deficiencies, we must fertilize the plants with the nutrients needed.

What are the excesses? Excesses are accumulations of metal salts in the metabolism of plants. To avoid excesses we must make a balanced and appropriate payment to the type of crop, substrate and cultivated genetics. Each plant genetics will have certain nutrient needs.

 Detecting deficiencies and excesses of cannabis nutrients

To detect an excess or a lack of nutrients you have to pay attention and observe the color and condition of the leaves. The leaves will show us what kind of lack or excess the plant suffers. As we have said, it is easier to correct a deficiency than an excess. Excesses are more difficult to solve because it is necessary to do a root wash, use a nutrient cleanser and provide enzymes to help break down dead roots.

All this implies a biological break in the development of the plant. The excesses will cause burns on the leaves and will alter the taste of the flowers. The larger the plant, the greater the amount of nutrients it will need. The deficiencies cause stress to the plant and we will cultivate weak specimens prone to be attacked by pests and fungi. The deficiencies will affect the final performance, obtaining flowers with less flavor, weight, size and power. To avoid nutrient deficiencies and excesses it is essential to measure, adjust and stabilize the EC (electro conductivity) and PH. By measuring the EC we will know the salt levels and we can adjust the amount of nutrients.

Keep in mind that sometimes the deficiencies and excesses are not only due to lack or excess of subscriber but also because of another type of problem that does not allow the plant to absorb the necessary nutrients.

Deficiencies and excesses of macro nutrients



Stems and leaves weaken

The green color of the plant intensifies

The inner leaves turn dark green

The internal water system (xylem and phloem) weakens

Marijuana tastes too much like vegetable


The plants are too small

The plant develops smaller and less bright leaves

The leaves turn yellow

Some leaves curl, discolor and fall

Premature flowering and low productivity



The new leaves are too thin and develop chlorosis

The leaves have burns on the tips and edges

The plant has less space between the nodes of the branches

The lower leaves curl and develop spots

The flowers once dried have a chemical flavor

The tips of the roots die Harvest decreases


Deceleration of vertical and lateral growth

Weak plants prone to diseases and pests

Petioles turn a dark purple color

The leaves turn bluish-green or dark purple

The leaves that are most affected develop a dark metallic bronze color, curl, wilt and finally fall



The new leaves are too thin and have chlorosis

The leaves show burns on the tips and edges

Less space between the knots

The lower leaves curl and develop spots

Root tips twist back


Old leaves turn pale and have chlorosis

The edges and tips of the leaves develop an oxide color and burn

The plant can develop more new stems

Flowering is late and less productive

The stems are weak and too thin in addition to fragile

Deficiencies and excesses of micro nutrients



New leaves wilt

Growth may show atrophy

The absorption of potassium, iron and manganese is blocked


Delayed plant growth and decreased harvest

The development of flowers is slow

Yellowish brown spots on the edge and surface of the leaves

The lower leaves begin to curl and curl

The roots begin to recede



Retarded growth

Dark green leaves


The plant seems weak

The deficiency already exists 4 to 6 weeks before it is evidenced externally

Brown / yellow spots and irregularities on older leaves

Old leaves dry, curl and fall



The plant is smaller than it should be

The leaves turn dark green

When the excess is severe both the tips and the edges of the leaves discolor and burn


New outbreaks develop weak and very slowly

The new leaves acquire a yellowish lime color and the growth stagnates

The veins of the leaves turn yellow

The tips of the leaves can sometimes burn, darken and take the form of a downward hook

If the plant also has a general lack of nutrients, the new stems develop long purple spots

The stem becomes lignified and becomes woody

Boron (B)


Yellow leaves that just fall


New shoots and roots grow abnormally

The new shoots are burned and twist

Black spots develop between leaf veins

The leaves are too thick and brittle

The new stems acquire an oxide color

The tips of the roots swell, discolor and stop growing

Manganese (Mn)


The new leaves have chlorosis, turn dark orange and develop brown spots

Damage appears earlier in young leaves than in older leaves


Younger leaves have chlorosis

The very affected leaves have necrosis, pale and finally fall

The edges of the leaves remain dark green surrounding the chlorosis

Symptoms spread from the youngest to the oldest leaves

Zinc (Zn)


Excess Zinc does not usually occur but when it occurs it is extremely toxic

With much excess zinc plants die quickly

Excess zinc produces iron deficiencies


Young leaves have chlorosis

The plant generates smaller and thinner leaves with a tendency to curl and wrinkle

The central stem and the new shoots are piled up

The tips and edges of the leaves fade and burn

Atrophy occurs in the space between the new knots

Productivity falls dramatically

Iron (Fe)


The leaves turn a bronze-like color, and the smaller leaves have dark brown spots

Prevents phosphorus absorption and the signs appear on the lower leaves


Young shoots and leaves develop chlorosis

As the deficiency progresses, the larger leaves show chlorosis in the nerves

The leaves can develop necrosis and fall

Lack of iron impairs phosphorus absorption and signs appear on the lower leaves

Chlorine (CI)


The leaves turn yellowish bronze and are smaller in addition to taking longer to develop

The tips and edges of the young leaves burn


The leaves turn yellowish bronze and the tips and edges burn

Newer leaves turn pale green and wilt

Roots develop thick tips and become ineffective

Copper (Cu)


Slower growth

Iron Chlorosis between leaf veins

Less branches growth

Roots weaken and grow very slowly


Young leaves and buds wilt, twist and sometimes die

The tips and edges of the leaves turn dark green first and then grayish and eventually die

Plant growth is slow and production is low

Molybdenum (Mb)


Excess of molybdenum causes iron deficiency

The leaves fade


The leaves start to fall

In cold climates the leaves turn yellow and with possible chlorosis

In short, cannabis nutrients are of the greatest importance for obtaining the best marijuana. It doesn’t make much sense to buy some good cannabis seeds and grow them without a fertilizer protocol that includes all the cannabis nutrients.

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