Loco1074answered grow question 4 years ago I went thru the same issue my 1st grow. Thought it was either magnesium, sulfur, or nitro deficiency. Tried the remedies and it didnt improve. As i searched for answers i found out in the end i needed more drainage which had caused nute lockout due to mild bud rot. It happened during early flower and my yield suffered as well as potency and size of colas. Correct this now during veg stage. Happy growing brother