Question: How do I get the seedlings ready to go out into the real world?

Answer: You need to toughen them up. Growers refer to it as “hardening” their plants. You need to expose them gradually, over a period of a few days or a week, to increasingly difficult conditions. They’ll get more sunlight, a little wind, and perhaps cooler weather than they have had in the greenhouse. In the case of summer sowings that you intend to plant into the garden during hot weather, harden them to the sun or they’ll cook within minutes of being planted out.