When you see leaves that are unusually dark, Nitrogen toxicity is the first culprit.
Toxicity of one or more nutrients can also cause lockouts of other nutrients such as Mn as Haze said.
The leaves becoming deformed is another sign that you have a problem.
You really want to FLUSH FLUSH FLUSH!!!
The final flush should be with a complete fertilizer including micronutes, applied at only 1/4-1/2 strength.
stinkyattic Reviewed by stinkyattic on . anyone know whats up with this?? you there stinky?? this is only on a few of my plants... looks like rust spots on other wise healthy leaves. then i got to looking a little more and some of the leaves are dark green and dry??? the plants were feed about 3 days ago. the temps are right on. Rating: 5