Nährstoffmangel?

Wirkt wie Magnesiumunverfügbarkeit. Entweder durch ungünstigen PH Wert verursacht oder eben durch Magnesiummangel im Medium. Sollte sich aber korrigieren lassen 😉, Happy Growing!

Burning from soil being too rich or feeding too much/too often. In soil, a schedule of plain water/plain water/fertilizer/plain water/plain water/fertilizer works well. Also, make sure your pots are not standing in water after you irrigate, they need to be moist not wet and need a wet/dry cycle. Water the entire pot until run-fff and then do not water again until the top 3cm or so has dried out completely ........then repeat. Another thing, always fill your pots rigt up to the top with soil, there is no point having good sized pots then only half filling them! Also. also, never start seedlings in clear plastic cups, roots need complete darkness to grow properly. If you are using fertilizers, use them less frequently or half the strength you are using now. If you are not using any fertilizers and the soil is too rich, there really is nothing you can do except wait it out unttil the soil moderates.

Yeah, doesn't look good. Are there two plants in that pot? Half the plant is below the rim of the pot. The roots might be root bound .Even the seedlings in your diary post aren't healthy. That's from either poor lighting or toxic soil but her environment is crucial to. Is the temp and humidity right. Is there airflow?At this stage in her life I only have to water about every 7-10 days, 5 gallon pot. Yours look like 3-5 gallon, but medium also determines that. If they aren't very light when you lift them then they don't need water. If you know you have been watering correctly and not sure about how she's been feed, then I would transplant into fresh soil although that would add some stress but she's really hurting now. There's even deformation of new growth. If nothing else, back off everything like the other comment said. Make sure PH is good in soil and water. Wouldn't hurt to check TDS in runoff . Make sure lights are correct and temperature and humidity. Take your time and don't try to rush the process. Good luck. There's many good videos on YouTube from successful home growers and what they do.

Looks like your plant is showing signs of stress—possibly from overwatering or nitrogen toxicity. The dark green, clawed leaves are a classic sign of too much nitrogen, and overwatering could worsen it. I’d let the soil dry out a bit and ease up on the nutes, especially anything high in nitrogen. Also, ensure your lights aren’t too close and you have good airflow. It could be a combo of things, but dialing those in should help it bounce back.

Either too much light or a deficiency Try calmag

da die Blattspitzen auch braun bis schwarz sind, könnte es evtl. ein Nährstoffbrand (Überdüngung) sein oder der pH-Wert ist nicht ganz korrekt

Hi friend, I actually think that it is an excess of brightness that is ruining these excellent shoots....remember that too much is not always a good thing😎.