Part I. Problems with nutrition, irrigation and light.

Use the following pictures so that you can easily and quickly diagnose your diseased plants. We from the team of have prepared useful tips for you.

Most problems arising from fertilization can be easily overcome by rinsing the system with pH neutral water containing half of the recommended concentrations for the given period of plant development. In addition to nutritional deficiencies, there are various insects, molds and other pests that can attack plants, which we will pay special attention to in Part II.

Before you roll up your sleeves and start planting, you should first make sure of the quality and origin of the seeds.


Nitrogen (N) Deficiency

Nitrogen is one of the important elements that plants need. It is an important part of protein, chlorophyll, vitamins, hormones and DNA. As a component of enzymes, it is involved in all enzymatic reactions and plays an active role in plant metabolism.

Development of the deficit:

- The larger leaves in the lower parts turn light green to yellow.
- The stalks of the smaller leaves acquire a purple color. Vertical purple streaks begin to appear on the stem, which are very specific for nitrogen deficiency.
- The leaves in the lower parts turn white and begin to fall.
- Growth is visibly slow, plants remain low, stems are thin, leaf formation is very weak and they are small.
- Yellowing and whitening also spread to the middle and upper leaves.
- Flowering starts forcibly, and the loss of leaves is already great.
- Significantly weaker harvest than expected.


The cause of the deficiency may be improper nutrition or fertilizers that do not contain enough nutrients. Substrates that contain too much fresh organic material can cause nitrogen deficiency because microorganisms bind to it. Much of the nitrogen can be bound, especially in the first weeks. It is released later, but it is too late because the plants are entering a flowering period when N is no longer so necessary.


- Increase the concentration of food in the solution and water the substrate well.
- Add nitrogen to the irrigation solution using urea, mononutrient, etc.

Boron (B) Deficiency


The leaves and roots show unusual and slow growth. The first signs of boron deficiency are unnaturally thickened tips. The new leaves show symptoms of chlorosis (yellowing of the leaves). Sometimes the stems become rough or even hollow. Symptoms of calcium deficiency may also be observed because boron is needed by the plant for calcium to be properly absorbed. Newly grown young parts are most affected by boron deficiency and may look as if they have been scorched or scalded.


Boron is not absorbed by itself if there is not enough potassium and nitrogen, or if there is not enough moisture. The plant may begin to show signs of boron deficiency if the pH is too low or too high. Rinse the system with pH-neutral water containing half the required dose of fertilizer and the problem will be solved.

Iron (Fe) Deficiency


Symptoms of iron deficiency can occur during periods of severe growth or severe stress and are characterized by yellowing of young leaves and branches. This is mainly because the iron in plants is not mobile. Younger leaves cannot pull iron from older leaves. With more severe iron deficiency, the older leaves and smaller veins in them will turn yellow.


- The pH around the roots is too high (pH> 6.5).
- The environment around the roots contains too much zinc and / or manganese.
- The concentration of iron around the roots, or in the irrigation solution, is too low.
- The temperature of the roots is very low.
- The environment around the roots is too wet, which makes it difficult to access oxygen.
- Ineffective root function due to damage, infection or dead roots.
- There is too much light reaching the irrigation tank (the light helps the growth of unwanted algae). Algae use iron for their own growth and also break down iron chelates.


- Lower the pH level.
- You can add iron chelates directly to the substrate.
- Improve vessel drainage, or raise the temperature at the base.
- Fliar fertilizers (for foliar application) with iron chelates are a good solution. If you use quality fertilizers with a hydroponic system, iron deficiency is almost ruled out.

The best thing you can do is add monosutrient iron or spray your plants with an aqueous solution of EDDHA (iron chelate) (max. 0.1 grams per liter) or EDTA chelates (max. 0.5 grams per liter).

Calcium (Ca) Deficiency


Signs of calcium deficiency can be difficult to formulate, as calcium deficiency is often accompanied by magnesium, iron and others. However, some of the main signs of calcium deficiency can be seen on the leaves, in the form of dead spots, cracks, or small brown spots. Another sign of calcium deficiency is when new leaves remain small, crooked and curly at the edges. Both the inside of the plant and the flower may show signs of rot. It is possible for the roots to become ill with a bacterial infection or die due to underdevelopment.


If the pH in the root zone is not balanced, your plant cannot absorb calcium normally through the roots. The first step is to ensure the right pH for your growing environment. Different varieties tend to have different nutritional problems, but calcium, magnesium and iron deficiencies often go hand in hand. Many gardeners use calcium-magnesium supplements (often called Cal-Mag) in case such a deficiency occurs. Once you add Cal-Mag and adjust the pH, you can already expect healthy growth within the same week.

Copper (Cu) Deficiency


The lack of honey in plants is manifested by curling of the leaves upside down, too weak growth and unusual coloring. New leaves may be dark and curved, while other leaves may have started to turn yellow or white. It is generally unusual not to have honey in the water or soil, as it is contained even in pure tap water. Copper deficiency usually occurs when there is a problem with the pH, so that the plant can not absorb it, although it is present.


Rinse the system with clean water with a neutral pH, this will remove the accumulated salts that can affect the absorption of honey and will help restore the required pH levels. Make sure the problem starts to fade within a few days. The old growth may not be restored, but the new one should be quite healthy.

When grown in soil, copper is best absorbed in the range of 6.0 - 7.0 pH

In hydroponic cultivation, copper is best absorbed in the range of 5.5 - 6.5 pH

Magnesium (Mg) Deficiency

Magnesium acts as a building block for chlorophyll molecules (green in the leaves), making it essential for photosynthesis. At the same time, magnesium plays an important role in energy transmission. Together with calcium, they are components of tap water and their content in it determines the hardness.


Older and not so old leaves under the flowering top will be damaged and magnesium will be transported to the younger parts of the plant. This distribution can be seen as rusty brown spots and / or cloudy yellow spots between the veins. A slight deficiency of magnesium will almost slightly affect the flowering, but nevertheless the development of flowers will worsen the symptoms of deficiency.

Development of shortage

- Traces of deficiency first appear around the 4th-6th week.
- In the beginning the color of the young leaves is not affected.
- The number and size of small rusty spots increases.
- Over time, the symptoms spread throughout the plant, which already looks sick.
- In acute magnesium deficiency, the young petals are also severely affected and flower formation is reduced.


Magnesium deficiency can develop due to inhibition of its absorption for the following possible reasons:

- Too wet, cold and / or acidic environment at the roots.
- High levels of potassium, ammonia and / or calcium (eg high concentrations of potassium carbonate in drinking water or clay soil rich in calcium) compared to magnesium.
- Limited root system, in a plant with high requirements.
- High EC in the growth medium, which prevents evaporation.


When the problem is defined, the best thing you can do is spray foliar with fertilizers containing magnesium sulfate. When fertilizing by irrigation, water with fertilizers containing magnesium sulfate monohydrate.


Correction of possible causes: when the pH in the soil is too low (below 5.0), use calcium-magnesium fertilizers (often called commercial Cal-Mag). For hydroponic cultivation, temporarily apply a solution with a higher pH (6.5). When the EC is too high, rinse and / or temporarily irrigate the plant only with clean drinking water. When growing indoors, keep the temperature at the roots around 20-25 degrees Celsius.
Interesting information:
A little more magnesium will not harm the growing environment. In soil cultivation it is difficult to get a surplus. Too much magnesium inhibits calcium intake and the plant shows the general symptoms of excess salt, stunted growth and darkening of foliage.

Manganese (Mn) Deficiency


The leaves turn yellow between the veins, with variegated brown spots on the affected areas. These dead spots can spread and eventually kill the entire leaf, which can also tear or fall apart. The growth of the plant is slower than usual.


Manganese deficiency is often caused by too high a pH, or in cases where the plant takes in too much iron.

If the manganese deficiency is in the soil environment, adjust the pH to 6.0 - 6.5. If it is in hydro - 5.5 - 6.0. Avoid higher pH values, because that's where you're most likely to run into manganese deficiency.

Rinse the system with clean water with neutral pH, containing half the required amount of fertilizer for the period in which the plant is located. Watch for improvement in the condition of the plant. You are expected to see a change in the next few days.

Phosphorus (P) Deficiency


Phosphorus is essential for root development, overall plant health and most important for the flowering period. Flowering plants love phosphorus and it is very unusual for phosphorus to come in more during this period. A plant that suffers from phosphorus deficiency will have slow, delayed growth. If the deficiency is severe, gray or purple spots may appear on the leaves.


Measure the pH of the system and rinse it. Excess Fe (iron) and Zn (zinc) can lead to phosphorus (P) deficiency. If you've tried everything else and it doesn't work, you can directly add more phosphorus to your overall diet and see if that helps solve the problem. In general, it is unusual to have more phosphorus when the plant is in bloom and harvesting.

Potassium (K) Deficiency


Older leaves first turn yellow, then dark scorched lesions begin to form around the edges of the leaves. It is possible for the stems to lengthen and become weak. The symptoms are very similar to iron deficiency, with the difference that the tips of the leaves curl and the edges burn and die.


Potassium is not well absorbed if there is too much calcium or nitrogen in the system. Check the pH levels of the water and rinse the entire system with water that contains half the usual concentrations of fertilizer for this period of the plant and watch if the plant will improve.

Molybdenum (Mo) Deficiency


The initial symptoms may look like nitrogen deficiency (yellowing of older, lower leaves). They may become variegated or mottled. However, the main signal of molybdenum deficiency is when the leaves begin to turn a unique orange, red or pink color around the edges, moving to the center of the leaves. Sometimes the flower begins to appear in the middle of the leaves and spreads to the tips.


Molybdenum deficiency is relatively easy to correct by adding small amounts of molybdenum to the soil, raising the pH of the medium, or by rinsing the system with pure pH-neutral water containing half the required amount of fertilizer for the plant. Observe if within a few days the problem begins to resolve. Molybdenum is locked in a lower pH environment. In soil it can be locked at a pH lower than 6.5. In hydro or soilless environments, molybdenum can be locked at pH 5.5 - 6.0 and lower. Try to keep the pH of your growth medium above these limits to avoid molybdenum deficiency.

Sulfur (S) Deficiency


Sulfur deficiency generally manifests itself as chlorosis (yellowing of the leaves), starting with the oldest leaves, and at first it is possible to confuse with nitrogen deficiency. The parts on the underside of the leaves may acquire a distinctive pink-red or orange color. The flowers of the flowering plant may begin to die. Unlike other deficiencies that cause chlorosis, with sulfur deficiency chlorosis starts in the opposite way - from the base to the tips. The leaves become hard and brittle and eventually fall off.


Check and adjust the pH of the solution to make sure that the sulfur is not locked. Sulfur moves very slowly in the plant, so it may take a few days after you solve the problem before you start to notice any improvement.

Zinc (Zn) Deficiency


The younger leaves turn yellow between the veins. The tips become discolored and begin to die. The leaves acquire an unusually folded shape and the plant stops growing vertically. The distance between the new branches will be very small, which will cause the newly formed leaves to twist into each other. If the plant has begun to form flowers, it is very likely that they will begin to die.


Rinse the system with clean water with neutral pH, containing half the required amount of fertilizer for the plant (mostly zinc, iron and molybdenum). Watch if the problem starts to fade in a few days.

Nitrogen overdose/poisoning


Dark green leaves, weak stems, overall slow growth. Nitrogen-fertilized leaves often get the so-called "Claw", or curved leaves with folded edges. Curling is sometimes observed, which is often confused with overwatering, but this is actually unique to nitrogen poisoning. Leaves that curl like nails often turn yellow and then die if nitrogen poisoning is not treated, as is the case with nitrogen deficiency, except that in case of overdose the leaves will curl more and more. Sooner or later they will turn yellow, then brown, and finally fall. It is easy to recognize if the yellowing is caused by too much nitrogen, because the rest of the plant will be dark green and the yellowing leaves will first curl like nails.
However, different plant species react differently to nitrogen poisoning. Some turn dark green without curling their leaves. Others will get the tips of the leaves to turn to a strange 90 degrees. Third species, or individuals, will begin to twist and turn yellow / brown and eventually fall, just as in a deficit. Still, these are all signs of too much nitrogen.


- Dark green color of the leaves and all green parts
- The tips of the leaves turn down, with no signs of overwatering.
- You may notice yellowing on the affected leaves or over time and manifestations of other deficiencies.
- Nitrogen poisoning, often but not always, is accompanied by food burns.
- The specific turn of "The Claw" often looks as if it happens by accident, affecting only a few leaves here and there.
- Problems with pH or high temperature will worsen the curl, as they further stress the plant and reduce its protection.
- Over time, the bent leaves will begin to turn yellow, form spots, and eventually die.


Reduce the amount of nitrogen you give your plants. If you apply additional fertilizers - stop. If you are in the flowering period, be sure to use fertilizers specifically designed for flowering, because otherwise you will have too much nitrogen.

What if we are not sure this is Nitrogen poisoning?

Too often, even among experienced gardeners, this specific curvature of the tips is confused with overwatering, pH or temperature problems.
It is also true that different types of stress on plants can worsen problems that are not the cause, which in itself is misleading for professional agronomists.

As we assume you know, every plant needs the element Nitrogen. In fact, nitrogen is one of the three main nutrients found in almost every type of fertilizer.
When you look at the label, there are almost always three numbers written, for example, 3-12-6 or 5-10-5 (N-P-K). These cleaners inform us about the percentage of Nitrogen (N), Phosphorus (P) and Potassium (K) in the bottle. Absolutely the entire plant world on Earth needs these 3 elements to grow.

Why is it necessary to treat and prevent Nitrogen poisoning?

- Plants that get too much nitrogen do not grow as vigorously.
- Excess nitrogen is dangerous especially in the flowering phase, because it will make the flowers too small.
- If you react quickly enough and reduce nitrogen levels at the first signs of poisoning, your plant will recover quickly.
Note: Some varieties to which “The Claw” or just “Claw” has been added tend to develop the characteristic curvature of the leaf tips to a greater extent than other varieties.

Problems with excess nitrogen are rare in nature. They can be seen much more often in home-grown plants, especially in very avid growers, who chase high results and sometimes imperceptibly overdo fertilizing.
There are varieties of one species that prefer lower levels of concentration of fertilizers compared to other varieties of the same species. In such cases, it is important to be able to recognize the signs of intoxication of the plant, regardless of whether all other plants / varieties in your garden are healthy.
One of the most common signs of over-fertilization is "food burn", or when the tips of the leaves look brown and burnt.

The relationship between light and the specific curvature of the leaf tips

- The distance between the leaves and the light source or the uneven distribution of light from the reflector (creating a hot spot) often affects the condition. This is why many growers believe that the light is somehow causing the problem with "The Claw".

-Note that the specific curvature appears on dark green leaves that do not receive enough light. Accordingly, the use of nitrogen contained in them becomes impossible and so they are poisoned with it.

The specific curvature in the flowering period

- If you use fertilizers for growth during the flowering period, your plants will receive too much nitrogen. For this reason, you should get fertilizers specifically designed for flowering. You will notice that flowering fertilizers always contain a lower percentage of nitrogen (the first digit of NPK) than fertilizers for growth. In some boosters it is even 0%.

- Many growers mistakenly increase the concentration of fertilizers and do not stop adding extra nitrogen when they see yellow leaves in the flowering phase, without realizing that it is completely natural for a plant to start turning yellow when the crop begins to take shape. Adding a lot of nitrogen in the flowering phase, even if the leaves are yellow, can cause nitrogen poisoning.

Note: In the last few weeks before harvesting, your plants begin to pull the remaining nitrogen from the leaves as part of the flower formation process. This causes yellowing of the leaves, starting from the base of the plant. This is part of the natural flowering process and you do not need to fight against it. You can see that the leaves always turn yellow in almost all pictures of large-flowered plants. If the leaves of your plants are perfectly dark green when harvesting, the harvest will be weaker.

Do not add excess nitrogen to the flowering!



If only the edges of your leaves are affected, you don't need to worry, but if you see that the problem is spreading, then you need to take immediate action before the damage becomes even greater. Other manifestations of fertilization are the appearance of spots in random places or twisting the tips down.


Rinse the system with plain water with neutral pH. Give your plants some time to recover, then start with more dilute solutions of fertilizers that should be given to them in the appropriate period, gradually increasing them to normal concentrations.

Light Burning / Heat Stress


The plant can tolerate a certain amount of heat and light. After some time, traces of stress begin to appear on the leaves, which are close to the source of light and / or heat. The leaves become yellow or brown spots. In general, places where there is too much light will look burnt.
If you touch the leaves directly with the lamp that is already hot, you will also get burns.
When the temperature rises a lot, the edges of the toothed leaves will curl, even if there is no burning or other traces of light stress.


Find a way to reduce the temperature and / or increase the circulation in the growth space, if heat is the problem. A small fan placed so that it blows over the tops of the plants will help prevent the formation of hot spots under the lamps.
If your plants receive too much light, try to reduce it, or move the source farther away from the tops of the plants.
If you are still a beginner, it will be easiest for you to try to keep the room at a comfortable room temperature at all times. If it's hot for you in the room, it's probably the same for the plants.



The leaves of the plants will start to sag if they are either overwatered or insufficiently watered. The symptoms of the two conditions are a bit similar. When watering, the leaves will be hard and curled down the entire length to the stalk. Chlorosis (yellowing of the leaves) may also occur.

Plants use their roots to absorb oxygen that is dissolved in water, or to obtain it from the soil in which they are located. When you water a plant, the roots stay in stagnant water in which no oxygen is left. The reason for the drooping leaves is that they actually die of oxygen starvation.


The best thing you can do for your watered plants is to leave them without watering for a while, after which you can gradually start giving them water again and things will return to normal.
If you feel that the plant environment is kept wet, you may need better drainage. Make sure the water drains freely from the bottom of the container (some experts recommend providing enough water to get at least 20% drainage each time you water the plants). Then do not water until you feel with your finger that the soil is dry and deeper.
If your plants are already overwatered, you can try to increase the temperature and airflow around the pots so that the water will evaporate faster. You can make a few light holes in the soil, for example with a pencil, to provide extra aeration and oxygen to the roots. For soil cultivation in general, it is good to water only when the environment is dry, and this is easiest to determine by feeling with the soil below the soil surface.
The other way to check if it's time to water is to lift the pot. When it is heavy, it is full of water and there is no need for watering, when it seems very light, it is time to water it. For plants other than soil, your watering method will vary, but if the plants are drooping and you give them a lot of water, it's a good idea to prune the waterings and see if they improve.
If you grow hydroponically with the roots of plants directly in the water and see signs of overwatering, it means that you have problems with the roots: Either you have root rot that prevents oxygen from reaching them, or you do not dissolve enough oxygen in the water (you can easily to increase the dissolved oxygen in the water by a simple air pump and a few air pebbles).

Root rot


The roots need water, but if they are exposed to water with bacteria, they will begin to rot. Roots that have been drowned in too much water without enough oxygen are much more prone to problems. Healthy roots are white to cream in color, while roots affected by rot are brownish and actually have a rotten odor.
Plants affected by root rot will spontaneously begin to lose their leaves, yellowing, drooping, or in other words with the appearance of dying. You will also notice that your plants will start drinking less water. If you notice these symptoms in your plant, it will not be bad to try all the suggestions below to stop root rot.

It is important to note that root damage is permanent. A regenerating plant will be able to make new growth, but its old infected roots will never recover. Root rot mainly affects hydroponic systems, but can also be the result of overwatering in soil or other growing media. In general, at any time when the roots are in water, they are at risk of rot.
- Your plants may look overgrown or dilapidated
- The roots are brown, slimy, with a bad odor
- The leaves often turn yellow
- The leaves begin to die and fall off quickly
- The plant drinks much less water than usual.


Getting rid of root rot can be quite difficult and for most gardeners it is much easier to just give up the plant and start over. However, there are proven techniques that will cure your plant from insidious root rot. To get rid of this problem successfully, you need to take action in two main ways. You will first need to treat the roots of the plants directly, and you will also need to change the environment in which they grow so as to avoid conditions that are conducive to rot.
If you don't fix the environmental causes of rot, it will just keep happening no matter what you do. Therefore, it is very important to go through each step of the treatment to make sure that there is no recurrence. It is important to mention that the affected roots will not recover, just as discolored leaves do not turn green again. What you are looking for as a result are new healthy white roots.

How to prevent root rot:
1. You will need to keep your growing environment as clean as possible at all times to stop the bacteria before they invade. Before you start growing, you must thoroughly clean all the elements involved in the growing process with white vinegar and clean water to remove all bacteria.
2. Some growers prefer to add beneficial bacteria or enzymes to the water to help prevent root diseases and absorb nutrients. Most such products can be used in both soil and hydro systems.
3. If you use a hydroponic system, it is best to change the water in the tank regularly to prevent the spread of bacteria throughout the tank.
4. It will be useful for you to get as much oxygen as possible from the water dissolved in the water. It is not a bad idea to get an air pump and large air stones for the hydroponic system. Rotting cannot take place in an oxygen-rich environment.
5. Make sure that the water temperature never rises above a comfortable room temperature. Warm water retains much less oxygen than colder water and creates an ideal environment for bacteria to grow. The maximum recommended temperature for the water in the tank is about 22 ° C. Try to maintain a temperature of 18 ° C - 20 ° C, which is optimal for growth and prevention of rot.
6. Ensure your hydroponic systems so that dead roots, leaves and other plant debris do not fall into the tank, because their decay creates ideal conditions for the growth of bad bacteria.
7. Do not allow light to the roots or water in the tank in any way, as it also provides ideal conditions for bacteria and algae.

Some gardeners recommend treating root rot with H2O2 (oxygenated water, or hydrogen peroxide. Adding hydrogen peroxide to water will kill all bacteria, including rotting agents. Its effectiveness in the system is 1-2 days, as H2O2 easily passes into Therefore, if you use hydrogen peroxide as a treatment, you will need to treat your solution daily to prevent recurrence.

Insufficient watering


If your plant hangs and you are convinced that it is not due to excessive watering, it probably needs water. When the plant dries, the leaves look loose and lifeless.


While it is good to let the soil dry slightly after watering, you should always water before the leaves droop. A good way to determine if a plant is ready to be watered is to lift it with the pot and feel whether it has weight or not. When the plant uses all the water in the pot, it will start to get lighter. If you need a weight comparison base, you can take an empty pot, fill it with the plant medium you are using and this will be an example of "dry weight". If you lift a potted plant and it is a little heavier than the dry weight example, it is time to water it. If it is much heavier, then there is still enough solution and no need to water it. Over time, you will get used to the weight and you will be able to determine the need for watering yourself, without using examples.