Terrible advice. Superthrive is SUPER concentrated and should NEVER be overapplied! I have seen people KILL their plants with the stuff! Seedlings should not be given any type of nutrients. If you really want to give them superthrive, use it at a rate of a drop per 2-4 gallons.
Also, spraying or misting seedlings is a common cause of damping-off and can leach what little nutrients the little plants off out of the leaves.

Water them lightly, but frequently, and if you are worried about disturbing the roots or damaging the stems with a strong flow of water, use a cheap diner-style ketchup dispenser instead. If you used nice light soil and have lots of drainage in your pots, and the pots are nice and small, you should not run into water problems with young plants. Don't give any type of fertilizer until the 5th set of adult leaves is unfolding.