Most common things to cause curling of the new growth?

Thread starter #1
I assume there are several reasons for new growth to curl. I have mothers in soil in a separate room, and Hydro/DWC in another. Two separate grows, separate feed, etc. Have curling in both. Corrected their pH after checking recently, but how long to recover if that was it?
 
If your leaves wrinkled from a significant PH fluctuation they will not recover and will remain wrinkled, the new growth is your main concern to know if you have stabilized your PH issue. If you leaves are curling and not wrinkled then it is more then likely not a PH adjustment issue, and rather a nitrogen issue. If your leaves are curling upward along the edges then it may be heat stress.

If you would like a better diagnosis pictures would be your best friend.