I harvest vegetables twelve months a year, can/freeze excess, and root cellar as appropriate. In the dead of winter the selection can get a little tight, but there's always something in the garden, freezer, pantry, or root cellar. In the Summer months, we're hard pressed to consume all of the bounty.
In the Summer I also get very pressed for time trying to get all of the tomatoes, eggplant, peppers, and zucchini in the freezer, and all of the cucumbers turned into pickles. It is so very much worth it though come Winter!
In late October we cover up six of the raised beds with a greenhouse. Under the plastic protection I continue to harvest spinach, lettuce, swiss chard, and salad onions through the entire winter. The key is getting the right varieties which can take the cold weather. Under the greenhouse the plants are protected from the wind and wet, but it's unheated, so they need to be tough. The plants grow very, very slowly in the cold, but they do grow.Generally the harvests work like this:
Spring: spinach, lettuce, salad onions, kohlrabi, cabbage, swiss chard, and sugar snap peas
Summer: beets, tomatoes, peppers, eggplant, zucchini, bulb onions, melons, cucumbers, carrots, green beans, garlic
Fall: beets, carrots, spinach, lettuce, salad onions, kohlrabi, cabbage, swiss chard
Winter: spinach, lettuce, swiss chard, salad onions
And here's where the produce goes that isn't eaten fresh:
In the pantry - pickles and sometimes tomatoes
In the freezer - tomatoes, zucchini, eggplant, green beans, peppers
In the root cellar - kohlrabi, beets, carrots, cabbage
I purchase onions, apples, lemons, and occasionally grapes at the store and pick strawberries and blueberries in large quantities in season locally and freeze. Everything else comes from the garden, pantry, freezer, or root cellar.