I have successfully taken and fully established five clones (10 weeks old) from my Durban Poison plant. I now want to switch them to bloom. However, I have recently noticed that some of the leaves on all the clones have specks on them - see photo1. I have checked for spider mites under magnification but can see no signs of bugs on either side of the affected leaves. Also, some of the unaffected/less affected leaves are curling and twisting - see photo 2. I have been very sparing on nutrients and water only when soil is dry.
Would really appreciate any ideas about what could be causing these problems and advice on how to deal with them.