White splotches on leaves...

Here is the worst of the two plants with the same problem. Both are KC Brains KC 45... Growing outside... As far as I know they are not supposed to be a purple strain, so I would guess that the purpling comes from a phosphorous deficiency. It's the white splotches on the leaves that have got me a little stumped tho... I would greatly appreciate any input as to what might actually be wrong with the plants...

too much nutes or too little nutes causes the stem to go purple also very low temps aswell i cant see the white splotches on the pics..but i think its powdery mildew and i got that on me plants its fungus systemic i used 9 part of water to 1 part of skimmed milk and soft sponge to wipe the leave then sprayed them with a 10% sodium bicarbonate water this will prevent the PM of growing on leaf again buy making the ph on surface of leaf high

The night time temps are still fairly low at the moment considering it's just starting spring here...Cheers for the information on the PM...