Well, without a diary here, about all I can tell you is that unless this is a purple strain, the red stem and trunk indicate a VERY stressed plant. The markings on the leaves show both a desperate need for more phosphorus and calcium... The very first thing I would look at is your pH... it needs to be between 6.0 and 6.5... anything lower than 6.0 and the plants aren't going to get the nutrition they need ... a little bit higher than 6.5 is ok but anything over 7.0 is not.
For the stem itself to be red is highly unusual ... you need to get a handle on your pH and your PK nutes...
Good luck....