Hi
I have lived in Lapland for 12 years in the border of Norwegian and Finland, I have use to build lasagna bed and growing vegetables on top of hot compost with some protection for the cold , very good for carrots, peas , salad and all fast growing vegetables, if you like other types of fast growing food, test: Saracens, amaranth, some cereal grow in less then 3months , some race of quinoa to , also parsley and others roots if you give them very rich soil or compost lasagna it's best , greenhouse with 2 cover will help a lot to .