I did notice last night that right where the roots are growing, there is a little itty bitty sprout of growth, just like Seattle_Aquarist said there should be. It's really itty bitty and hard to see, but it's there.
I'm pretty new to planted tanks, but I've been fertilizing them what seems to me quite a bit, but it's the recommended dosages on the bottles...they all have root tabs under them, they have been getting Seachem Flourish 2 times a week, Seachem Excel 3 times a week, & API Leaf Zone once a week. Once all this liquid stuff is gone, I will be making the transition to dry ferts, because I can see this is not the way to go as I keep adding more tanks, but it's the way I went since I am so new to ferts right now.
I do have a little bit of water lettuce in each tank and have wondered, if due to having such a high nutrient sucker in each tank, if maybe I should up the dosages on the ferts....but being so new to all this I am afraid of hurting the fish somehow....so far, none of my water tests of indicated any spikes, but I am not sure if there is something else I should be testing for that wouldn't show up on the basic tests. Right now, I just use Tetra 6 in 1 test strips. I plan on getting a better test kit, when money allows, but in the last month or so I have spent a lot of fish stuff....