Regular observation of the appearance of cannabis will help to get a lot of useful information about the condition of the plant. Water or light disturbances, a lack or excess of mineral elements, disease, stress, cannabis parasite infestation – all have outward signs that give the grower a distress signal and a plea for help. Timely intervention, in most cases, can minimize the negative effects, with no loss in the quality and quantity of the future crop.
The difficulty, however, is that many problems with very different backgrounds manifest in similar ways. After receiving the signal that “something has gone wrong,” the grower’s job is to determine the root cause, using the clues that the plant provides. This will require knowledge of the symptoms, the ability to regularly measure and monitor growing conditions, and the ability to compare and analyze the findings.
Slow growth, general plant weakness
If the plant is not exhibiting any symptoms of stunting, you can probably look for the cause in the basic parameters. Stunted growth can be caused by too high or low temperatures, poor cannabis lighting, lack of nutrients in the soil or hydroponic solution. It can also be the first sign of narrower problems, but to start with you need to eliminate the basics, bring all parameters to the recommended values. First of all, equalize the temperature, light and humidity, and check (if possible) the condition of the roots and the pH of the soil.
Wilting of the leaves and the plant as a whole
The first thing to pay attention to in this case is the correct watering. Lack of water rarely occurs, mainly in remote areas during hot, dry weather. After making up for the deficit of moisture plants quickly recover, without consequences for the future harvest. Overwatering is much more common, especially with overzealous beginners. Overwatered roots are deprived of oxygen, suffocate, and stop supplying the plant with enough moisture. This is why the symptoms of over and underwatering are so similar. To identify the problem, just check the moisture content of the soil: if at a depth of 3-4 cm it is dry – underwater, if wet at the very surface – definitely overwatering.
Discoloration of plant tops
Burning of the upper shoots and leaves is a definite sign of light scorch of marijuana. Unlike cases of mineral imbalance, where brown and yellow-ochre colors predominate, light burn causes the tops of the plant to take on a characteristic whitish or pale yellow color. When these symptoms appear, evaluate the wattage of the lamp and the distance from the lamp to the cannabis plant. More often than not, increasing the distance from the light source to the top parts of the plant can completely solve the problem.
Yellowing of the leaves (chlorosis) is a sign of quite serious problems in the development of the plant. The yellow color is caused by the destruction of the green pigment (chlorophyll) responsible for photosynthesis. A uniform yellowing of the marijuana leaves, with no spots, stripes or pattern starting from the bottom, very likely indicates a nitrogen deficiency. The grower should analyze the composition of the applied fertilizer and adjust the content of this nutrient. At the same time, near the end of flowering, near harvests, the yellowing and dying off of the lower leaves is a natural process, indicating that the end of the plant’s life cycle is nearing.
Leaf spotting, drying out of plant parts
In most cases, this symptom indicates a deficiency or overabundance of a wide range of micronutrients. Brown and rusty brown spots can appear with an imbalance of potassium, calcium, magnesium, boron. Drying of leaf margins is most often the result of a chemical burn caused by a shock dose of some chemical. It is hardly possible to identify the specific element that was the culprit of the plant’s ill health. In this case, the best solution is to wash or transplant the cannabis bush and then feed it with a carefully balanced fertilizer. Spots can also be the result of a significant pH difference – this must be checked and, if necessary, corrected.
Light and dark spots
The spots which usually appear on the inside of the leaf are a result of parasites and pests (thrips, aphids, mites). To detect them in good time, you need to inspect your plants regularly. The earlier the pests are spotted, the easier it will be to deal with them. It is highly desirable to solve problems with insects before the beginning of the flowering stage of marijuana – at this time you can still use cardinal potent agents, which are undesirable to use later, when the hemp is already in bloom.
A white dusty coating is a sign of powdery mildew, a fungal disease of hemp. Fungal spores are airborne, very tenacious, and can be transported long distances. In the outdoors, infection is most likely in the spring, when overwintered spores come to life and affect the plant’s shoots, ovaries and buds, and young leaves. Hemp growing indoors is also not immune to powdery mildew infestation – spores enter the grow box through the ventilation, with the inflow of air. To combat the disease, chemical and organic fungicides are used, as well as folk remedies: solutions of soap, soda ash, ash.
Spider web, which covers the leaves and branches of the plant – a sign of spider mite infestation. Actually, the characteristic spider web appears in the already quite neglected stage of the lesion, and measures will have to be applied urgently and drastically. Spider mite multiplies very quickly, and can kill cannabis in a short time. Before applying insecticides, it is necessary to eliminate conditions that contribute to the reproduction of spider mite: lower the temperature (if growing in closed soil), provide ventilation – spider mite does not like drafts and clean cool air, regularly spray plants with a sprayer, even clean water, knocking out the adult mites and preventing them from reproducing.
Wet spots on stems
The appearance of brown soggy spots on the stems signals to the grower that the plant is infested with rot. Grey or white rot is a fungal disease that develops in conditions of high humidity and low temperature. Lack of proper ventilation and sunlight aggravate the situation. Spreading, the fungus affects all parts of the plant (stems, leaves, inflorescences) except for the cannabis root system. Treatment for this disease involves spraying with a copper-soap solution or fungicides. If it does not have the proper effect, the sick bush will have to be removed to avoid infecting neighboring plants. So the grower is better to focus on prevention: maintain proper temperature and humidity, choose varieties resistant to mold and rot for growing in the open ground, provide ventilation and sufficient lighting. For outdoors, periodic spraying of marijuana plants with Bordeaux liquid is relevant.
As you can see, regular inspection of the plants and observation of their appearance helps to identify cannabis problems in time, and take measures to eliminate them at an early stage.