I would never prune seedlings.

Potting them up if they're leggy is just fine.

He doesn't even mentioned the fact that if you pinch out the main leader stem with determinates or dwarf varieties you've doomed the plant completely as in RIP for any production from those types of tomato varieties and why anyone would prune small seedlings at all really does escape me when there are better alternatives such as transferring those leggy seedlings and planting them deeply.

Carolyn

thanks, Carolyn. I thought it odd that I had never read about doing that here.

Its lack of light that make plants leggy ,not the heat

dickie, I have read that it can be due to either lack of light or heat. I don't know if that is true or not, but there are many who claim it to be true.

My seedlings get a minimum of 7 hours of full sun and most days 10 hours so I don't think lack of light is the problem.