I use starter cubes, or when I use soil (like up potting) I just use my own soil from my garden, and give it a feed if the plants say they need it.
This year I just used the only soil that was available at the store. The grounds still frozen haha, I can use it for other starts if I do them. Just my early starts are done, being peppers and tomatoes.

Gets funner, we have Microclimates too. Some communities can grow gourds, while others are just shit out of luck without greenhouses.
I’m oversimplifying, but gets the point across.
That’s exactly it. just rockwool starter cubes. Precut and has a hole in it, but you can also just buy sheets.
Heatmat to keep temp and humidity up, I do also use H2O2 as well with my water to keep mold/mildew down.
I use double cups with the solo cups so they don’t sit in water, the inside cup has a hole in the bottom, this allows me to bottom water, as well if I top water I can drain the excess.
That’s an option, but not in my climate, by the time they root, they’re too far behind to fruit. I trim off a few branches and bury the suckers usually.
There was a couple cultivars that didn’t sprout, I’m still giving them some more time.
The issue here is the 90 day frost free days. We can get up to 120, but that’s doubtful, and peppers also stunt under 15c, so long before frost is an issue. So you need decent sized plants to throw out at the end of May. Anything that continues into Sept and still produces is bonus.
Most tomatoes also stunt under 10c, so without extra cover, your growing days for these plants are a couple months at most.
Edit not my province, but great info.
Yes, they are common stock for my other endeavors.

Just expanded clay pellets holding the starter cube in place in the cup(holder?) for the aeroponics.