Im very sorry to bump this thread back up to the top, since its been so long, But I am having the very same symptoms as the Original Poster, and my leaves appear the same.

Does anyone know what problem this actualy is? Mine are about 5-6 weeks old, in 40% pearlite 60% potting soil. I tested the Ph and it is generally 6.3-6.8. I did a NPK test and found it to be low on N & P but overfed in K. I thought it may have been over watering originally but I am not sure now. Any help with this would be greatly appreciated.

Sorry again for the semi-necro.