using canna veg nutes
so your thinking overwatering or lack of nutes?
as for being stubborn. ive grown from clones in perlite using the same nutes (crappy ones at that) for about 6 years. its only since ive become friendly with the local hydro store guys that i have caught up, if you will, with things. im using coco now, 2 part nutes and a ton of extras on the side, new methods (SOG, warehouse). but who knows i might get bored or enthusiastic one day and think fark it and foliar feed
stranger things ahve happened
Guys hes growing in coco not soil,coco has no nutes he has to add some,it looks like your ph might be a little low and maybe a cal mag defencie.The plants also looked overwatered!!!