large Plant leaves yellowing

Hi

I was speaking with a friend of mine today about the great info and help I had received when I posted here and she asked if I could take a look at her plant. my experience is limited but am reading and learning all the time. I grabbed as much information as I could

Its outdoors
50 liter pot half filled with loose but what appears to be reasonable quality potting mix
Canna Vega 5ml per litre, 5 litres every 3 days last 3 months...nothing for last 2 weeks except a light dose of Seasol 10ml per 5 litres and one feed of Canna Flores about 7 days ago at 5ml per Litre and 5 litres in total
Soil Ph 3 weeks ago was approx. 7 (color chart)
3 weeks flowering

There has been a large loss of leaves turning yellow since it started to flower and as you can see by the pics the yellowing is not just fan leaves it is also new growth. When you first see it the impression is it looks about 50% yellow or dead leaves and that is not including the handfuls that have already been removed. The yellowing extends to the top. I noticed a broken branch that still seemed like it was attached however the foliage had drooped and it looked dead. If you zoom on the second picture you can just see it. My guess is possibly root bound, causing lockout, so plant feeding off its self. I am not experienced enough to know what exactly is going on so would appreciate any comments.

Cheers

At 5 weeks in to flower it appears to be fairly normal as the plant will draw upon food reserves to devote to producing flowers. If it is indeed root bound, it may be too late in the game to take any corrective measures as re-potting/transplanting is typically done during the vegetative stage to mitigate stress. Personally, I would simply increase the dosage of your Canna Flores with inclusion of Cal-Mag if possible to help rule out those possible deficiencies. Just be sure to use a accurate pH meter before feeding as potential lock out issues are more likely caused by a low pH vs. being root bound. Cannabis can often thrive despite what appears to be root girdling.

plant looks sativa; 5 weeks is only 35 days of flowering it could take another 105 days to finish up, i would feed it more

Thanks for the help and I will forward your suggestions and update in a couple of weeks with a really healthy looking photo...all going well