Black tipped sugar leaves.

[Tersky]

Its hard to make out colors in the pic due to lighting but to me it looks like deficiencies. If temp does not get below mid 60's F (19-20 C) then i would say it is a deficiency issue .You are using coco so what are you feeding it?

Alternatively since it is an auto it may be getting close to harvest and may just be going through fall. Depends on strains flowering time.

[george66]

It is getting near to harvest but 1 of my other plants thats a couple of weeks behind is also starting to show the same symptoms.Feeding Canna A+B 5ml per 6 litres of water with 3 ml calmag and a few days back i started to add 2.5ml of Blackstrap Molasses,it was just after starting with the molasses that i noticed the black tips which is why i thought that might be the cause.

[kingfish]

george66, I don't see anything wrong with your plant. Leaves change color when they get close to harvest. Two plants from the same mother plant can look different just like your siblings don't all look the same. I wouldn't do a thing this close to harvest. Don't give them anything but water.