When you cultivate, sooner or later you run into problems. As a friend says: “He who cooks and kneads, everything happens to him.” Any activity with a certain complexity entails “problems” that, over time, you realize that they were not really problems, but part of learning. One of the main problems that every grower has encountered once in his life is finding yellow leaves in his marijuana.
If you involve living beings in these activities, we have the added difficulty that they can die, you have to hurry to find solutions before this happens and time passes quickly in a crop.
If we specify in our hobby, growing cannabis, we also have to bear in mind that our other hobby, smoking cannabis depends on the success of our harvest. This requires us to have certain knowledge of botany and biology, very simple, to be able to smoke without accessing the illegal market. Today we are going to help you with a problem that usually appears sooner or later in all crops: The yellow leaves in marijuana from our crops.
Chlorosis, the scientific name for this disorder, is not really a disease, but a symptom of different deficiencies that we will see below. Our plant is not performing photosynthesis in any of the leaves and that must have a reason, normally that the plant cannot assimilate nutrients or that these are not available for various reasons. After determining that the number of yellow leaves in your marijuana is excessive, becoming something unwanted, you have to investigate a little more to see the root of the problem. Let’s see what the causes are, how to check it and how to solve it.
Normal causes of marijuana with yellow leaves
First let’s see when it’s not a problem yellow leaves appear in marijuana.
At the end of flowering
In the last two to three weeks, this is most likely to happen For several reasons: the same age of the plant makes it weaker and needs to shed a leaf to end its life cycle, think about autumn, the plants prepare for winter, dropping their leaves, already dry, or directly die.
After a root wash
Also if you have washed the roots to prepare the harvest or used a nutrient cleaner, or have simply stopped feeding them for a few days, it is possible that it is missing some food and takes it from the most expendable leaves. During this phase it is likely to happen because of the great effort you make to form your flowers. It needs all the energy possible and sometimes draws reserves, and the leaves are a good source of energy, very fast and easily available.. There are some varieties that kill almost all the leaves around the completely yellow buds. Don’t worry, it’s part of the normal growing process.
Marijuana problems with yellow leaves
Let’s see now some causes that should worry you.
Excess salts in the soil
This can happen in many crops in the flowering phase, they can partially block the roots. You have to act quickly, because the resulting cannabis will “scratch” more in the throat when smoking and will not give you the production that it should, since the plant does not have enough food available and the buds will be excessively fluffy. In some cases the plant will stop growing and will barely give you production. The lack of elements causes the plant to not be able to photosynthesize in some leaves due to lack of nutrients to build chlorophyll.
To check that you have an excess of salts you need a dish to collect the water to be analyzed and an EC meter.
Method for growing in a pot: water the plant a little, when it has absorbed the water, water it again. You must repeat the process until water comes out from underneath and check the EC of this. This must be adjusted to the values in this table (column EC), although, depending on the variety it may require more or less food, it is always better to be a little lower than to exceed these values. In case they are above, you should wash the roots until the EC value is within the marked limits. You can also use Flush, a product specifically designed to clean the soil and roots of excess nutrients.
In mother earth it is more difficult for them to block, since the roots can spread over a much larger area. In case you suspect this has happened, fill a pot with soil close to the plant and go through the process described above. In case you have a very high EC, use Flush and do not feed the plants until the EC is correct or you verify that the chlorosis has been solved.
A poor quality substrate that does not dehydrate properly or does not retain nutrients well can cause many problems in our marijuana plants.
A substrate that retains too much moisture could cause rot in the root system, drastically reducing the health of our cannabis plants. and therefore its performance. In case of a bad substrate, a large number of yellow leaves will be seen throughout the marijuana plant, both in the young and in the old ones.
We recommend reading the article on the best soil for marijuana if you want a quality substrate.
Lack of food
If your plants lack some element necessary for photosynthesis, it is impossible for them to do so, which is why yellow leaves will appear on your marijuana plants. Also, this will cause them to forage on their own leaves and quickly wilt. The problem usually happens in the growth phase, when they are creating the structure that will support the buds.
Vegetative growth is carried out with the help of large amounts of nitrogen which is the most demanded by the plant at that time and can create deficiencies if there is not enough available. It is essential that the plant develops correctly so that the production is adequate. Here you can find a selection of the best fertilizers on the market for the growth phase.
ANDexcess or lack of irrigation
It is also a possible cause of the appearance of yellow leaves in our marijuana. This requires cycles of high and low humidity in the substrate, without it drying out. If this is not the case, the plant cannot perform its functions correctly and may again cause a shortage of some of the elements necessary to carry out photosynthesis. In this case it will be the upper leaves and especially the new ones, which will appear with this coloration.
Lack of irrigation can also produce chlorosis, as there is no availability of water and therefore of nutrients dissolved in it, to feed the plant and carry out photosynthesis correctly. Our plants must always have a certain degree of moisture in the soil.
Take a look at our article on watering, here we explain how to know if you water a lot or a little and how to correct it.
Exposure to light
Another common cause that can lead to the appearance of yellow leaves in marijuana is low exposure to light. In case it is deficient, the first leaves to acquire this color will be the lowest, since without light it is impossible for them to carry out photosynthesis. You will have to prune the lower branches and leaves that do not reach the light and make sure that the position and height of the lights is correct in case of an indoor crop.
The excess light causes burns on the upper leaves, although they are usually easy to detect and find out what caused them. As in the previous case, you must check that the position of the bulbs is correct, take temperature measurements in the highest area of the crop and make sure that it does not exceed 28º, from this temperature the plants cannot photosynthesize. This in addition to causing the appearance of yellow leaves in marijuana will not allow optimal fattening of the buds.
Cold temperatures can make some plants transform into something even more beautiful, there are plants that are dressed in golden, violet, purple, red or very dark green colors. This usually happens at the end of flowering, when the manufacture of chlorophyll is in decline as it is no longer so necessary for the plant. As if they turn yellow we have already commented that it is normal, but if this happens at the beginning of flowering we must be careful and check the temperatures both day and night of our crop. Climate control devices are essential in any cannabis cultivation, as it is the way to know that the plant is in the range of physical conditions that will make it perform its functions correctly.
Taking into account that the appearance of yellow leaves in marijuana grown under intensive conditions are related to food and nutrient availability, we cannot forget one of the factors that limit this availability, the pH. Depending on the level of acidity or alkalinity, our plants will be able to assimilate some elements and others notIt is very important, for proper nutrition and to avoid deficiencies that cause chlorosis, to have a pH adjusted between defined values. If you want to know more about the importance of regulating the pH, we suggest reading the article What is the pH of water? How to measure and control it?
These are the main causes of the appearance of yellow leaves on our marijuana plants. If you have any questions, leave us a comment below. And if you liked the article, share it on your social networks!