Earlier quoted context omitted.
Northern countries don’t have the soil. Even if you take it for granted that the water, heat and sunlight will be there, it takes millennia to create good farmland. Even with heavy investment it would take decades. Vertical farms would work, but those work almost anywhere.
What??? Do you say that Denmark, Sweden, north Germany, Poland, and the Baltics can't grow crops due to lack of good soil?
Most of Scandinavia is recently emerged and you can use your hands and a wooden stick to remove the vegetable soil and uncover the silt that was at the bottom of the ocean a few hundred years ago. And before that, that silt was dirt mixed in the ice. So, there is not a lot of organic anything there.
However, I think that soil is good enough. With the huge caveat that I'm not an expert by any means, I do believe that fertilizers and greenhouses would work. Also, you can make soil with some organic refuse and rudimentary industry. It's more of a question of all the other factors (labor) can be put in place.