Gelbe Blattspitzen

Hi I checked out the diary. In some photos, there's green algae buildup on the soil, so it could be A) pH problems due to waterlogging. Lift the pot to see if there's water in the middle or bottom of the pot by the weight, because the roots may not have reached the whole pot yet. Or B) pH change due to over-fertilization (ions K+/NO³- etc., that have accumulated in the substrate). This can show effects on the most sensitive strains because the fertilization schedules from manufacturers are usually too high since they want to sell more, and it might work under optimal other conditions. At least reduce the NPK stuff by 30-50%. Cheers

Zinc deficiency. A dose or three of a soluble trace element/trace mineral mix applied to the root zone should cure this quite quickly. Soluble trace element mix should be available from any quality garden centre.

Start your correction by flushing before anything. Not magnesium, that starts at bottom and moves up. Look up iron deficiency in marijuana images. Closest I come to your picture. If it is the problem iron chelated, oxides or sulphite supplements are fast absorbing. Both foliar and watering should be applied. In a pinch use rust water. Iron deficiency is often found in combination with Zn and Mn deficiency. If iron deficiency you may also have PH problems.

Could be a boron deficiency, but that'd be rare in soil.

Hey there, what PPFD are you using? Could be light stress. In this phase, I would work with around 500-600 PPFD :) Best regards

Hi bud. As the leaves are otherwise lush and dark green, I'm gonna guess it's an excess of magnesium turning your leaves that fluorescent color.

The most common nutrients that cause issues that show up at the leaf margins is potassium, magnesium and copper. The first two are complementary and work together while copper is a base micronutrient that isn't needed in large quantities. I also see a little bit of rust spots on older leaves that points to calcium. If you're not supplying any CalMag, you might consider it. If you already are, it's probably your pH.

You use tap water ? Maybe chlorines, maybe potassium excess, definitely too much of something. Doubt that its ph or light, most probably either wrong NPK formula, or excess of some elements in water by default.