Gardens are important, but not going to help anyone in Canada in November.
The only way to protect your food supply here at this time of year is food storage. Whether you grew the food you're storing or bought it from someone else, that's all that can help you when the stores have nothing to sell. Go ahead and try and grow yourself enough food at this time of year in Hope, Merrit, Princeton, etc. It's dark and -10oC in a lot of those places.