BioBudsanswered grow question 4 years ago This is a calcium deficiency, this can be caused by growing with LED light and not feeding enough Cal/Mag supplement. Or a overwatering problem, your plants leaves are hanging down or PH problem where your water is to high in PH above 6.5 / 7 where minerals cant be used by the plant. So add a calcium / magnesium supplement if you tested PH and soil is normal and dry. For direct results: spray the leaves (not the buds) with some calmag solution with the ventilation higher and tent open until dry.