I decided to transplant my spring onions/green onions into a window box container so I could fit more in there. After a while I noticed that they weren't as green as the new ones I was placing in the window box.

Why have they become less green over time? Do they need fertilizer? I have some all purpose miracle gro fertilizer I could put. I also have that turf granules to make the grass grow. Also, I read that onions have shallow roots, but how shallow is shallow? When I transplanted them into this window box pot, their roots were wrapping around the dirt in their previous container, which was about 6 inches deep. I was surprised since I read they were shallow. This box isn't much bigger, maybe about an inch taller, so I was wondering if I should move them again as well. Old picture of previous container