Biggie and Smalls (Watermelon Auto)

Both plants started to get their typical purple coloring a couple of days ago, but now is really noticeable. I am thinking of harvesting Biggie by the end of this week, this will be Day 77(since sprouting) and letting Smalls to flower a week or two more than Biggie. Today is day 77 and I am harvesting both of them. Strangely, Smalls has a lot more amber trichomes than Biggie, but the buds are way less developed...