If one plant seems to be taller than the others around it, it’s not a good sign as this weakens the stems. The appearance of spots on the leaves will be the symptom to follow. Firstly, you’ll see those necrotic spots characterised by their brown tonality. This time with chlorotic ones, characterised by a white colour. The veins of the leaves will keep their green colour, unlike many deficiencies.
What you’ll notice shifting colour are the petioles and stems, now showing red tones. Although previously, you might’ve noticed the plant stretch out, it was not growing. Leaves will grow small in size, and this is when the deficiency becomes most dangerous. They move around the plant very fast, unlike most deficiencies. This one will spread to the larger fan leaves where it will most likely kill them. Before implementing any changes to your grow medium or watering solution, take a look at your lights. With strong LED and HPS grow lights, you might be overheating the leaves. These will show burn symptoms even if the overall temperature is cool.
Move your plants further away from the lights for a couple of days to determine the root of the issue. In case lights are not the problem, the deficiency might be caused by an excess of fertilizers and nutrients. Excess salt is especially common as it tends to build up in the growing medium. Nutrient lockout is a very common cause of most deficiencies. When the pH of the soil is too low, it makes the medium too acidic. This causes stress in the root zone and prevents the uptake of potassium. When it comes to the pH issue, make sure you establish and maintain a healthy pH throughout the entire life cycle. In soil grows, the pH value should be fairly neutral, between 6.0-7.0 for the optimal potassium uptake. As for hydro systems or coco coir, a slightly more acidic pH would be recommended. Use neutral pH water to remove the excess nutrients in the soil. Only include half of your usual nutrient solution in the water. Proper watering practices will go a long way in keeping a plant healthy. The method and frequency with which you water will impact your future buds massively. Make sure you read the labels of your supplements to see how these nutrients interact with each other. Calcium and nitrogen will decrease the absorption of potassium, for example. Just be sure not to use too much of something without a full understanding of what it does. You can always use a supplement rich in nitrogen, phosphorus, and potassium. Give the plant time to recover and be on the lookout for the newer leaves and how they grow. When plants suffer from a nutrient deficiency, they are weak and have little resistance to disease. This is why it’s important to know how to detect and fix the deficiency in time.
If not enough is supplied, your buds will lack flavour and smell. The flowering stage is where you’ll most likely face a deficiency like this. Hopefully, you’ve learned more about potassium deficiency and all deficiencies in general. Next time, you’ll be able to fix this problem comfortably and in a timely manner.
Only through experience will you be able to obtain the best yields you can. Deficiencies are reversible and easy to solve if you know what you’re doing, and now you do.