I live in Estonia but the weather is allmost same here. I start my seeds in march, i let them grow like 5 cm then i move them outdoor into cold frame(see on picture) it's fantastic the sun will heat it up and plants are safe and warm there.
If you want you could move them in for night but i do not. i have this box with little heating inside so they wont freeze, its nice way to start your plants outside little bit earlyer than others This is not picture of my cold frame, mine is isolated with rock wool and instead of glass i have plexiglass( i think it will keep more warm inside than regular glass)
:rastasmoke: