Ben Falk, author of "The Resilient Farm and Homestead", refers to cold temperate regions such as his Vermont homestead as "storage climates."  In other words, long daylight hours in the summers create a glut of surplus food for the fall harvest, while the long winters that follow are linked to "lean months", unless there is adequate food STORAGE capacity.

If VERMONT is thought of as unreasonably cold, then where we live up here in hyper-continental central Canada is bordering on insane; we have annual temperature fluctuations of 80 degrees Celsius (-40 to +40) and less than HALF of the annual precipitation of Falk's New England home. We are lucky to get 100 frost-free days most years and winds routinely exceed 90km/hr.

Of course, as Falk points out: "the problem is the solution"...There are advantages of a long, cold winter when it comes to storing food.  Too bad root cellars are not part of our local building codes!

While it is easy enough to grow and store an abundance of fruits and vegetables, there are greater challenges associated with growing our staple CARBOHYDRATES.  Most permaculture homesteaders I read about in our climate are not growing a great deal of traditional cereal crops--and there are difficulties in processing broad-acre crops such as wheat, especially without machinery.  Without the raw caloric power of staple carbohydrates, we are a long way from any sort of meaningful food autonomy or security.

Inspired by Falk's experiments growing RICE in Vermont (something which nobody was doing, but which proved to be feasible), I began looking for calorie-dense crops that could be grown here and stored with minimal processing.

I LOVE root crops... carrots and beets not only are delicious and relatively easy to grow, but store for most of the winter with next to no processing (I simply pull them in the fall, cut off the greens and pack them in peat moss in my root cellar)...  I wanted something THAT EASY for my staple carbohydrates.

Potatoes are a good start, but they are very pest-prone over here, and often succumb to molds, blights, or other diseases during storage, so it isn't reasonable to RELY on a potato harvest to get through the entirety of the winter 'lean months'.

That was when I discovered a blog post of someone successfully growing sweet potatoes in Ontario... granted a little farther south, but perhaps I could sufficiently bolster my night heat and frost-free days with raised bed 'cold frames'?   I decided to give it a try.

I started 'slips' from 3 organic sweet potatoes I bought at Safeway back in February. This process was no different than what most of us did back in grade school (skewers supporting the sweet potatoes in jars full of water).  As the slips grew, I rooted them in water, then transferred a bunch to pots in a greenhouse when my windowsill became too crowded.

I was quite late getting my cold-frames organized, and as a result, didn't get the slips outside until mid-to-late JUNE... so I was not overly optimistic about my yield.  Then I was away from home for a week following planting, and the slips suffered without my babysitting (watering and opening/closing the cold-frames).

Nonetheless, I harvested 10-12 kilos of small but edible sweet potatoes from 2 small raised beds in early October... Success!

Next year, applying what I learned through this experiment, I think it is entirely realistic to grow 100 kilograms or more sweet potatoes in a relatively small space next to the house in Zone 1.

Apparently sweet potatoes should be cured at high temperature and humidity (32 degrees Celsius, 90% RH) for approximately a week following harvest, and should then be stored just below room temperature for several MONTHS before eating them (it takes that long for the sugars to develop). I managed to do this with a little supplemental heat in my greenhouse.

The beauty of sweet potatoes is that they 'mature' for consumption at just about exactly the same time that the potato harvest starts deteriorating. (plus they don't require a root cellar!)... to say nothing of their nutritional claims, which are impressive.

I'm keen to hear from anyone else with experience growing sweet potatoes in extremely cold climates... it seems as though this is an endeavour that more of us should look into.

-Tim