to be honest it looks pretty damn healthy and usually a little discoloration will happen check pot size maybe need a bigger pot , check ph, also the spots on the stem is fine thats just natural growing. Other than this everything seems fine or should seem fine also amke sur your using nutrients properly they're easy to use but very hard at the same time so make sure your using them right also that they arent locked up. it doesnt look like its locked but maybe on its way? keep up the good work, definetly.