organic grow..need help please.

[sus]

hi i am new here. i need some help.
i grow some big bang autoflowers in plagron all mix..20 liter pots..they are from 18/12 2013. i feed them only rain water. the light is 600watt and it is 75 cm away on 24/0. temp is 24-26.
i need a little help,the leaves is twisting in the top and some got rust color..
what am i doing wrong? please help..

 

[VRZ711]

M8 you have P and K deficiency probably water PH problems, you can foil feed them and check you water, and whats the humidity LV? and how does the leaves feel like when you touch ?

 

[edk3335]

M8 you have P and K deficiency probably water PH problems, you can foil feed them and check you water, and whats the humidity LV? and how does the leaves feel like when you touch ?

2nd that check your ph, its most likely on the alkaline side

 

[LarryOG]

Looks like there was a day or two of heat stress to me.

 

[Purplekrunchie]

The brown tips are a sign of nutrient burn. What are you feeding them? You put organics in the soil? Did you add too much? Organics can burn still, the process is just a little slower. New growth being twisted is a sign of calcium issues, but get the burn handled first.