Nutrient burn on cannabis leaves
What it looks like
Tips turn brown and crispy, starting at the ends and walking back. The rest of the leaf can stay dark green. This is too much feed, or a medium that has dried and concentrated the salts.
What usually causes it
Stop feeding and water with plain pH-adjusted water until runoff is reasonable. Cut the next feed in half. Burned tips do not turn green again. Watch the new growth.
Check this first
Dark green leaves, clawed tips, burnt ends, usually after a strong feed. Plain water next. Do not fix burn with more bottles.
This is identification for a home grow. It is not a pesticide label and not medical advice. Follow your local law.