That means something is lacking in your soil. A complete living soil will not be light on the nitro at the end, it will still have more than enough to keep the plant green.
Keeping it green is important in organics becuse it means trich production is in full swing up until the very end when the leaves begin to change color, then fade.
What you have here is the entire plant at once, and evenly so. If this was a light issue, it would be the tops only. If it was feed, it would move from bottom up, just the way you see it in hydro grows. In soil, this is pH. How much lime is in your soil?