The stems of cannabis are mostly green when they are at their healthiest. If the stems appear red, most of them indicate that the cannabis is in an unfavorable growth environment.The most causes of cannabis red branches are:
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Causes of cannabis red branches 1 :Excessive light
Cannabis branches and trunks exposed to strong direct light for a long time will turn red, pink or purple. If this discoloration is not distributed on all branches, but on some branches that are not covered by leaves, this is mostly the reason. This is the defense mechanism of plants, which can prevent overheating damage from excessive light. This situation mostly occurs in outdoor summer planting and indoor planting with HPS lights.
After this happens, there is no need to rush to adjust the light. Check the cannabis leaves first. If the cannabis leaves do not burn, this situation can be ignored. After that, the stems of marijuana will become more and more red and purple. If the marijuana leaves have light burning, you should measure the light with a light meter and the light intensity should be appropriately reduced.

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Causes of cannabis red branches 2 : Heredity

Some purple cannabis and dark green cannabis will grow branches of different colors. The color of the stem and the branch are similar, but the shades are different, resulting in a gradation of the upper and lower colors of the cannabis structure and a gradation of the inner and outer colors. If this color gradient is natural, then don’t worry at all, just immerse yourself in the visual enjoyment brought by the cannabis plant.
Causes of cannabis red branches 3 : Excessive temperature difference
This cause of cannabis red branches mostly occurs in areas where the temperature difference between morning and evening is large in the north, and it also occurs when air conditioning is used for heat dissipation in indoor planting. This situation usually occurs after a sudden drop in temperature. The cannabis stem is slightly damaged, and the protective liquid is secreted inside, which looks red. After this happens, the transportation capacity of cannabis stems deteriorates, the growth rate slows down, and it takes a long time to recover. After experiencing severe temperature fluctuations for many times, the stem loses its transportation ability, and the cannabis plant will wither and die.
Most of the marijuana that this happens are damp-loving varieties, or you have slightly overwatered marijuana for a long time. Too much water in the marijuana body will reduce the ability of marijuana to keep warm.
Causes 4 : Complications of root problems
The stems and branches function mainly to support the structure and transport nutrients. When the roots of cannabis have problems, the stems and branches will transport fewer nutrients and become red. Root rot, excessive watering, and overheating of the roots can all make the branches and stems of hemp red. When your cannabis appears over-watering, root rot, leaf spot disease and the branches turn red, it means that the roots of your cannabis are suffering. While the stem changes color, the cannabis is not far from withering.
If this happens, it is over-fertilization, you can wash the soil first. In other cases, put the marijuana in a low-light, cool-ventilated, relatively dry environment, and give her a week or so to recover slowly.
Causes 5 : Nutritional deficiency
On the premise that the roots are healthy, if the cannabis plant is decolorized as a whole, the leaves look yellow and white, and the branches are red, this indicates that the cannabis lacks nutrients. Of course, this is only on the premise that the roots of the cannabis are not damaged. This situation is very common in hydroponics, and cautious growers over-dilute the culture solution, causing cannabis to lack nutrients. If it occurs in soil culture, we should give priority to whether hemp needs a larger pot (the largest leaves grow out of the pot), and then consider adding fertilizers. You should note that the regular flower soil on the market can basically meet the nutritional needs of cannabis when grow hemp for the first time. Even for the strong-growing cannabis, nutritional deficiencies generally appear after the middle and late stages of the growth period.
Causes 6 : PH fluctuates or is inappropriate
Strong pH fluctuations can damage the roots of hemp, and a pH that is too high or too low will hinder the absorption of mineral elements by hemp. The problem of PH is the same as the manifestation of nutritional deficiencies in cannabis. The essential problem is that the roots cannot absorb enough nutrients, but the root of the problem is different. Magnesium deficiency and phosphorus deficiency can cause the symptoms of reddening of branches. The lack of these minerals is generally due to pH fluctuations or inappropriateness, rather than lack of fertilizer.
In order to grow the best quality cannabis, you need the following professional PH test pen, or for large-scale cultivation, you can consider a more professional wall-mounted device that monitors PH, PPM and water temperature in real time, as follows
Use PH regulators and other methods to adjust the soil. For details, see Weed Grow Lesson 15: Prevent excessive fertilization.
The redness of branches and stems is mostly a sign of plant diseases. Fortunately, it appears earlier and gives us plenty of time to find out the problem and correct it.