Plant yellowing need help!

Ok so I'm growing in a pc case it's in auto flower stain and the temps are at 72-78 always I'm using pro mix ultimate organic mix with some worm castings added. My plant is 43 days from seed and started yellowing and the tips are like a purplish color I have no added nutes as of yet so I'm ruling out nute burn unless the soil is to hot which I doubt it any help would be great thanks

That's deficient in everything. Give it food, check the ph of the soil (6.5-6.8, definitely need some calcium and magnesium. Feed it its starving to death.