The question is what crops to start when for different climates... There's a lot of info out there for starting winter crops early...but I haven't seen a bunch on starting crops early in seeding trays to increase the number of crops you can grow. Do you look at the dates of when you're supposed to grow them and just try starting them in seeding trays early?
I have a calculator for that. I'll see if I can dig it up to show you how it works.
Have you seen this before?
https://www.clydesvegetableplantingchart.com/
Here is something I have used over the last couple of years to know when to start seeds inside or outside depending on the average last spring frost!
https://www.clydesvegetableplantingchart.com/