Case in point, here is an example of how important it is to maintain leaves in a healthy green condition. I added a little too much blood meal to my potting soil, didn't get any burn though and that's what's important. The side benefit of maintaining leaf health is getting a double harvest too. Harvest #1 - snip the cola at a point where it turns from a "fat can" to airy buds, and place the plant back under the lights to bulk up them up, for harvest #2....it makes a big difference in overall yield.
42 days into flowering with LOT'S of chlorophyll:
70 days into flowering. Cola is about 24" long, about 3" - 6" in girth:
Harvest, fan leaves looking pretty worn but still hanging on:
Cola macro showing very dense bud structure: