Northern Lights Auto Grow

Day 15 I checked soil moisture level with probe and I think I'll wait another day to water again. #2 Is strange compared to #1 as it is starting it's second set of leaves at the first node instead of the top. Day 18 #2 looks to be getting to main tops now for whatever reason it stopped at the second set of leaves and just started growing from the first node. Day 20 I Mixed GH Armor Si with my water and pH'd to 6.4 Gave both a good soaking. I think I may have been underwatering trying my damnedest not to overwater. Day 21 I wonder if I was underwatering if that would be enough stress to cause early flowering. I noticed pistols at several nodes on #1. I'm only 3rd week in on this grow.