Can i save these? and how?

I've got 6 white widows going, all in miracle grow moisture control with CFL's 18/6, I had 3 stunt after transplant into big pot and I had 3 get huge on me. This is my first grow so I'm not really sure at all what to do, if they can even be saved. I put a pic of my main healthy plant, she was planted the same day as the other 3 so you can see how big the difference is in the same environment.

hows your ph? the mg soil might be throwing that off in those three.

I'm not sure how the ph is, I know I should be checking though. I've been letting the water sit for 24hrs at the very least before using it though. I just don't get how 3 are doing so well and 3 are struggling and damn near dead. I'll start checking the soil ph though, I just need to go get a meter somewhere. The one I have doesn't seem to work at all