Makin' it happen: Artic gardening

I don't have anything new to post, because nothing new is happening: almost all my tomatoes are still green, the squash is still producing, the new plot is still weedy (although a lot less so!)

But this article on MSN made me happy: greenhouse gardening above the Arctic Circle. I'm surprised that the greenhouse doesn't need any additional heating! But, that makes it a perfect example of how much one can do without artificially changing the environment: simply make a room with a clear ceiling and let the 24hr sun do all the work. Too bad it is commercial and not a community garden, but it sounds like they do a lot of educational outreach.

The lady interviewed in the article commented on how 24hrs of sunlight sped up the growth process, allowing plants to grow/mature faster than normal during the short 59-day season. But what about photoperiodism? Doesn't night length signal flowering (either short or long night length, depending on type of plant)? If there's no night, how do plants know to flower and produce fruit?
Also, I've learned from indoor grow lights that different wavelengths of light cause different types of growth in plants. Doesn't the sharp angle of the sun up north influence the relative amounts of different wavelengths of light?