Hi
@Goudasan! You're having a Calcium and/or Magnesium deficiency. This probably comes from a wrong pH in your waterings. Do you test the pH level of your waterings? As an emergency move, I would flush the soil with plain pH'd water (6.0) for 2-3 days and let the soil dry, then give it extra calcium and magnesium intakes by putting some Cal/Mag into your waterings. Hope this helps, keep us up-to-date and happy growing!