Некроз

The spots are likely caused not by pests or disease, but by uneven watering and a slight nutrient imbalance. In a large 50-liter pot, 5 liters of water is usually not enough to fully saturate the entire substrate. This creates dry and wet zones, leading to uneven feeding and the appearance of spots, especially after watering. Your PPM and pH values are generally normal, but with uneven moisture, salts can accumulate and cause temporary nutrient lockout. This often manifests as a deficiency in calcium or magnesium. The best solution is to water more thoroughly. Water the pot until there is a slight runoff, then let it dry out well before the next watering. Keep the pH stable between 6.2–6.5 and don’t increase the nutrients for now. If the problem persists, you can add a bit of CalMag. If new leaves are growing healthy, then the issue is resolved. The old spots won’t disappear—that's normal.

Hi Here is the analysis of your stains: ​1. Diagnosis: Beginning of Calcium / Magnesium deficiency (Cal-Mag) ​Symptoms: Small brown/rust spots scattered on the leaf blades are classic signs of a lack of Calcium. ​The cause: With a pH between 6.0 and 6.5, you are in the right range, but such a vigorous plant in a large pot consumes a lot. If she sweats very quickly (constant need for water), she can locally deplete these nutrients. ​PPM: 700-800 PPM is a good value, but if the plant grows explosively, it may require a micronutrient boost. ​2. The “Watering” factor ​You put 5 liters, which represents 10% of the volume of the pot (50L). It's the bare minimum. For a pot of this size, you could go up to 7 or 8 liters to properly saturate all the soil and avoid dry areas where the roots cannot draw nutrients. ​The fact that it is thirsty so quickly shows that its root mass is huge or that your temperature/ventilation is very high. ​3. General condition ​The plant remains very vigorous overall. The green is beautiful and the spots are still discreet. There is no absolute emergency, but we must correct the situation so that it does not spread. ​My recommendations: ​Slightly increase the water volume: Increase to 7L per watering to ensure that the bottom of the pot is moist. ​Addition of Cal-Mag: Add a supplement of Calcium and Magnesium during your next two waterings. This is often the weak link when a plant grows very quickly under LED or outdoors. ​PH stability: Try to aim for 6.3 consistently, this is the “sweet spot” for the absorption of Calcium in Biobizz potting soil. ​Your plant is an “athlete” that consumes a lot of energy. The spots are just a little reminder that she needs more minerals to support her rapid growth. I hope this will help you. I wish you a good day and good crops.

She needs a calcium and magnesium supplement. Otherwise, increase the dosage if already using one. Leaf symptoms are a direct reflection of what was happening in the root zone 2-3 weeks ago, they do not appear overnight due to one watering.

Time to feed 😎