Why my leaves curling up

why are the leaves curling up? Temps around 23-24 c.. been feeding them greenplanets dual fuel .. not sure if this is heat stress or Overwatering... I have been very careful with the watering so I really don’t know

Leaf edges curling upward always indicates a over heating issue. But if your temps are always 23-24c, then I would be looking at your environment humidity level, and if that is in check, then you are watering to frequently! Cannabis plants love having their roots saturated, but they also grow best if you let them dry out between watering. How to know when to water... when leaf stems arch downward, it is time to water, when leaf stems point straight up, and the leaf actually arches downward, the plant has been over-watered!

Hey yeh I have a small heater going and I think that might of caused it ...(maybe I need a new thermometer) . Humidity is always pretty low around 35 to 50 (I have ordered a humidifier and just waiting to come in mail) I hear you with the watering .I have been watering when the coco gets partially dry on top ..is it recommended to let the surface dry out before a water +feed?