What's this?

Could also be a virus.

Check for pests. It may be variegated which it should grow out of.

Magnesium Chlorosis for sure , it’s a deficiency. Leaves stems and the petioles of the leaves are purple as well. First , check the soil by analyzing the drain of the pot to verify the EC and pH levels of the soil. If the soil is in good conditions and sure that you’re not overwatering the coco, the last factor is too intense light. Magnesium chlorosis is a symptom of a photoinhibition.

You are right, too much light, since no stretch and twisted leafes. At this Stage 500 ppfd would be fine.

hi...... 50-60% reichen in diesem Wachstumsstadium, mit dieser Lampe völlig aus......! kann sonst schnell in Lichtstress ausarten😉 Vielo Glück

Hi Buddy From the photos: • Overall color is healthy green • Older leaves look fine • New growth is a bit tight, crinkled, slightly twisted • No burn, no necrosis, no spotting This points away from deficiency and more toward environment + light intensity. ⸻ The key factors you mentioned • Week 2 veg • Coco • EC 1.1 • pH 5.8 • 400W LED • Light was at 100%, now turned down to 90% Your feed numbers are actually fine for this stage. The plant doesn’t look hungry or toxic. ⸻ What’s most likely happening This looks like mild light stress / intensity mismatch, especially for week 2 veg. At this stage: • Roots are still developing • Coco dries fast • Strong LED light can push transpiration faster than the roots can supply That causes: • Tight, clawed-looking new growth • Slight leaf deformation at the top • Plants looking “busy” instead of relaxed Nothing serious — just a signal. ⸻ About the light A 400W LED at 90–100% in week 2 veg is often more than needed unless it’s very high. Better targets for this stage: • 60–75% power, or • Raise the light a bit more You want: • Leaves relaxed • Slight praying at most • No tacoing or twisting at the top Turning it down was a good instinct 👍 You could even go a little lower and see how she responds over 48h. ⸻ What NOT to change right now • Don’t increase EC • Don’t chase deficiencies • Don’t add CalMag yet unless symptoms progress • Don’t overreact to the look of new growth Give the plant time to respond to the light adjustment. ⸻ Simple checklist going forward • Keep pH around 5.8–6.0 • Maintain consistent coco moisture (don’t let it dry too much) • Ease the light intensity • Watch new growth, not old leaves If the next set of leaves comes in smoother → problem solved. ⸻ Bottom line • This is not a deficiency • This is not damage • This is a mild, early veg adjustment issue • You already made the right move by dialing the light back Plant looks healthy overall — just needs a little less push right now 🌿 Good call asking early. Growers Love my friend remember this is just my humble opinion, always trust you instinct and keep us posted 👊