

I am crocheting a Hexa cardigan and the granny squares made for the back are falling short of length. What should I do?
Hello Everyone! I am new to this page.
I will attach a picture for your better understanding.
Like I said, I am making a hexa cardigan.
( For those of you who are not familiar, it's like crocheting two big hexagons, laying them flat in L shape and sew the back leave the front voila! A nice cardigan)
So I decided to make granny squares for the back instead of just sewing the two sides to have a nice design on the back.
The problem is, the granny squares are not fitting the size.
Is there any way I can knit between the spaces? What should I do? And how?
TL;DR
Granny squares made for back of the cardigan are falling short of length. Should I crochet/knit/sew Between the spaces? If so how?
If not, what should I do?