Ok, assuming those plants are actually in soil, then there should be a whole host of mineral nutrients available to them. That said, it looks like they're getting close to outgrowing their containers.
These next subjects are a bit lengthy, but if you go to my thread The Charts, you'll find some, you know, charts in there. The ones I would like you to look for are the VPD charts and the pH charts. I still believe that it's pH that's causing the twisting and crepey appearance on some of those plants.
Your observation that some of them are doing well is your introduction into multi-cropping, or rather it's a demonstration of how different strains react to how they're being cared for.
So the soil that you're using looks about spent, if you're not going to repot them just yet into new soil I would suggest feeding something like Fox Farms Big Bloom, starting at low rates (I usually start at about 1/8th the recommended dose, then work my way up or down depending on how the plant responds). Pay attention to pH parameters, in soil you want a range in the mid 6's (6.2-6.8
generally), so media plays a role here you'll see.
Learn about vapor pressure deficit (VPD) and you'll learn why
@Toaster79 thought your plants were cold, I did, too. It is, in a nutshell, the plant's heart, its circulation system.
Cal-mag only is a feeding program I've never heard of before, it only addresses two of the 17 required minerals, and I'm willing to bet that whatever they had you buy is only a 2:1 or 3:1 ratio of Ca:Mg, which is bereft of Ca. (I'm using periodic table symbols here, ask if we're not being clear and we'll flesh it out). The plants still need N, P and K.
If you don't already, get yourself a basic vegetative growth fertilizer, it doesn't have to be the one I mentioned above, but it should provide at least N, P and K (if that's all it provides you'll have to make sure the soil mix makes up for the rest) with N being the highest number.
Beyond this, I suggest looking through the GrowFAQ at upper left. :)
