Good time to populate the empty cells. With a pair of tweezers, you can gently lift a couple starts from the healthy but overcrowded cells and move them to the cells without a healthy seedling. They have so few roots that they move easily.
Your link proved "invalid" ,at least from my view. What is it you're using. I use Superthrive and miraclegrow. Which reminds me , while its raining again today I need to track down some more Superthrive.
I'm using Plant-Prod 10-52-10 water soluble fertilizer.
Bob, would you think a high application of epsom salts hinders combustion ?Just make certain that the K is not from muriate of potash or any other chloride salt, since high chloride causes a marked reduction in tobacco leaf combustion.
Bob