• Yellowing lower leaves: what it is, and when it’s nothing Before anything else: if you're six or more weeks into flower and it's only the bottom leaves, this is probably normal.
• Natural senescence: when yellowing leaves are supposed to happen Late in flower, your plant starts dismantling its own fan leaves on purpose.
• pH lockout: why feeding more makes it worse A plant can be surrounded by a nutrient and unable to use it.