Big problem mates!

To diagnose these kind of problems there's a few steps. First of all is documenting whats happening visually: - Leaves curling up - Leaves with brown patches - Tips are drying - The problems are located somewhere particularly or all over the plant? If it's all over did it start bottom or top or randomly? Then we look at what we have been doing: - How much water we're giving them - Are they drying enough or are they constantly wet? - What nutes are we feeding them? On that stage they could be suffering from Phosphorus deficiency. (check pics on groweedeasy.com - diagnose) - https://www.growweedeasy.com/cannabis-plant-problems/phosphorus-deficiency - CHECK 3rd PICTURE. Finally if we need to undo something wrong in terms of feeding: -Flush with pH'd water ranging 6.0 - 6.5. - Do this only when the soil is dry otherwise you could cause other issues. -Mix some nutes on next watering and check EC of feeding water and runoff (the water that ends up in the tray). - Check guides on how to read EC