Clone leaves thin and curling down

Hi, it's hard to say and this sounds like a problem that can have various causes. Here are some possible reasons and solutions: Nutrient deficiency: A lack of certain nutrients like potassium, phosphorus, or magnesium can cause the leaf edges to darken and dry out. Check the nutrient supply and make sure your plant is getting all the necessary nutrients. Overwatering: Too much water can cause the plant's roots to not get enough oxygen, which can lead to dry and brittle leaves. Let the substrate dry out completely between waterings. Pests and fungi: Pests like spider mites or fungal infections can also cause the leaves to darken and dry out. Check the plant for signs of pests or fungal infestations and treat accordingly. Excessive heat or light burn: Too much heat or direct light can burn the leaves and cause them to dry out. Make sure the plant is not too close to the light source and that the temperature in the growing area is controlled. I hope these tips help you identify and fix the problem. Good luck with your grow!

The symptoms seen are probably carryover of the cloning process. some have healthier rooted clones than others. If it was kept in a high humiditty / low vpd environment until you tent, it may just be adapting. It'll be a bit more sensitive to dry atmosphere or higher vpd. What's on that leaf? Can't even diagnose that, lol. If from a foliar spray, definitely stop that. Also, a blurry white spot on same leaf on the leaf blade pointing left in picture looks like a smeared WPM colony. hopefully it is just a water stain of some sort. clones can be risky... when produced en masse, some portion inevitably have mold and such when money is inovled. Better to ask forgivness than permission type behaviour... i.e. sociopathic.

Either soil is too "hot" or they have been over fertilized. Give it a week or two, they are sure to bounce back soon enough.