When to start katana roots?

This is a topic that causes some division, some growers have a good reason to use it only in the first half of veg, others have a good reason to say that it should be used only in the last half of veg. I'm in the middle, i say use it all the way thru veg, just start out small due to the size of your seedling, you don't want to over-do it, and if you do it just right you may speed up the growing process and grow a more resistant plant, because a strong root= a strong plant. Hope it helped.