I thought seed starting mix was a scam until I tried it in my garage in Lansing
I always used regular potting soil for starting tomatoes and peppers because it was cheaper, about $6 a bag versus $12 for the seed mix. Last month my neighbor Carol showed me her seedlings in her garage under a cheap shop light, and hers were twice as thick with way more roots. I tried one flat with the seed mix and one with my usual soil, same seeds, same window, and after 3 weeks the difference was obvious. The seed mix drained better and didn't crust over, so the stems came up without that damping off problem I kept getting. Has anyone else switched and noticed the same thing, or did I just get lucky with this batch?
Seed mix is way lighter so the roots can actually push through instead of fighting compacted soil, that's why you got thicker stems. Been using it for years and the damping off thing basically disappeared once I switched, so not luck.