copper deficiency/over heating

i am growing indoors in soil and thought everything was going ok,
but the past 2 days ive noticed the edges of some leaves slightly curl upwards(not the tips).after looking around here for a couple of hours it seems it could be the heat or a copper deficiency i can lower the heat no probs but how the feck do a heal a copper deficiency?????

I heard also that it could be humidity issues. I believe possibly low Humidity and high temps. I would research some more before attempting to correct. From what I understand, all issues can be unchanged save for burning of plants. Also correct one problem at a time.
Good Luck

cheers man i appretiate your advice,as it sounds like the most sensible way.