Why cannabis leaves turn yellow
Cannabis leaves are a main pointer of a plant’s health condition. Only green leaves with correct form are capable for 100% to participate in the process of photosynthesis, and transforming the light energy into chemical energy in best quantities. If the marijuana leaf begins to turn yellow, then this meaning that something has gone wrong. It will be possible to resolve the problem only when you can find the reason for its occurrence. You have to do the next steps. \
What cannabis leaves turned yellow?
Cannabis leaves are able to change their color over time. Old leaves at first start to have dark green color then are lighter. Sometimes it becomes so yellowed that and it means illness. In fact, there is nothing terrible on this. These leaves should simply be cut. That is why over time they begin to consume more vital energy than they produce. Defoliation allows the plant to concentrate on young leaves and inflorescences, which has a positive effect on productivity. Most often this happens with large "fan" leaves.
Conditions of cultivations
Cannabis leaves can turn yellow when the cultivation conditions are bad. Most often this is when the temperature and humidity is raise. If the thermometer readings are above 30 degrees for several days, then there is nothing wondering that the leaves are yellow, especially if the humidity was above 60%. You just need to lower the temperature to 23-27 degrees and ventilate the grow box well.
If only those leaves are yellowed that are so close to the light, then that is mean a light or temperature stress. That lamp shines very brightly, or it substantially heats the air near this leaves. Whatever it was, the grower needs to increase the distance from the light source to the plant.
Also, yellowing may occur due to insufficient watering of cannabis plant. In this case, the problem will be systemic. Typically, the down leaves will be wilted. After watering, everything will be ok. To prevent this you should check the degree of dryness of the soil every few days at a depth of 3-5 cm. When it becomes dry, then the plant needs to be watered.
Pests and diseases
If young leaves begin to turn yellow, then the problem can be classified too serious. First of all, the grower should inspect all the plants. If the problem is in all plants, then it is a system. Often this occurs appear of mold, fungi or insect pests. To know for sure, you have to inspect the bushes with a magnifier.
At first you need to check the underside of the yellow leaves. There can be mites or larvae of other parasites. You should also examine their upper side for damage by gray rot or powdery mildew. Next, pay attention for the topsoil. So often, there can be aphid, which causes significant damage to the roots of the plant. Because of that, they become unable to absorb nutrients normally. As a result, the plant begins to feel their lack.
If the foliage turned yellow in the entire greenhouse, then the problem is a system. That is mean, plants are deficient in nutrients. First of all, it is worthwhile to understand that the lack of micro and macro elements can arise not only because of the stinginess of the grower for nutrients, but also because of its excessive amount. Especially often this happens when using inorganic fertilizers, which are salts that accumulate in the soil. As a result, the pH of the soil changes and the plant becomes unable to absorb all the necessary chemical elements from it. The name of this phenomenon is nutrient blocking. Grover’s run into it often than with ordinary underfed plants.
Marijuana leaves can acquire a yellow color due to a lack of such nutrients:
• Nitrogen. Yellowness begins to appear on the leaves. If this happens on the eve of the harvest, then there is nothing wrong on this;
• Potassium. The edges of the leaves become light or yellow. When the problem is worse, appear dark spots;
• Magnesium. Yellow spots with dark dots appear on the lower and middle leaves. She begins to bend up;
• Sulfur. The leaves begin to be pale, get a yellow color. Their tips bend down;
• Manganese. On young leaves, the veins start to be yellow. Later, the problem appears on older leaves;
• Zinc. The tips of the leaves turn yellow at first and then brown;
• Iron. New leaves begin to turn yellow from the stem. Later their tips bend up.
The best way to prevent all these problems is to monitor the pH and EC levels of the soil. The first should always be between 5.5 and 6.5, and the second at a level of 0.75-2.0. Also, regular soil flushing will not be superfluous. You have to do it not more than once a month. It will be especially useful when the cannabis will transfer to the flowering stage.
*All information provided is for informational purposes only and is not a guide or call to action.
** We remind you that the use of marijuana seeds as a sowing material (cultivation of cannabis in order to obtain a plant) is crime in many countries.