Staying with the energy theme, building and using your own root cellar will definitely free you from dependence on electricity for a significant portion of your food storage. In addition to showing plans and various stages of construction, the links at the bottom of this post also show some rough and ready root cellar substitutes that basically involve storing the veggies in the garden, with some enhanced protection.
Root cellars, or their equivalent, have been around for thousands of years. They were probably first constructed in the Middle East. The peoples of those lands would have discovered early on the coolness of the earth only a few feet below the surface of the ground. Lower temperatures in caverns would have provided a significant clue to the benefits of underground storage and the cool refreshing water drawn up from wells were an everyday example of natural refrigeration.
There are definite examples of recognizable root cellars in Europe dating back to the 1600’s. When Europeans came to the new world, they brought their knowledge with them. Root cellars became a staple of pioneer life in the New World.
How Cold Will It Get?
How cold your root cellar can get will depend on your climate, the type of soil you have built your cellar in and the level of humidity. The soil temperature below the frost line varies about 6 degrees C, over the year. A properly vented root cellar uses the colder fall and winter air to keep temperatures closer to ideal for vegetable storage. At night the cooler outside air flows into the root cellar, pushing the warmer air out. During the day, the heavier cold air stays in place, keep your stored produce cold. The warmth of the earth at 6-10 feet below the surface will keep your vented root cellar from freezing. In addition, a dirt floor provides natural humidity control to help keep your vegetables in top shape.
Vegetables last for months because they are still alive while in storage. They are living off of the stored nutrients they have accumulated during the growing season. The cooler temperatures inside the cellar slow their metabolisms down, so the growth is minimal.
Storage Times for Various Vegetables
| Vegetable | Ideal Storage Temperature (°F) | Relative Humidity (percentage) | Average Storage Life |
| Beets | 32 | 95 | 1-3 months |
| Cabbage | 32 | 90-95 | 3-4 months |
| Carrots | 32 | 90-95 | 4-6 months |
| Celery | 32 | 90-95 | 2-3 months |
| Garlic | 32 | 65-70 | 6-7 months |
| Horseradish | 30-32 | 90-95 | 10-12 months |
| Jerusalem artichoke | 31-32 | 90-95 | 2-5 months |
| Onions | 32 | 65-70 | 5-8 months |
| Parsnips | 32 | 90-95 | 2-6 months |
| Potatoes | 38-40 | 90 | 5-8 months |
| Pumpkins | 50-55 | 70-75 | 2-3 months |
| Rutabaga | 32 | 90-95 | 2-4 months |
| Sweet potato | 55-60 | 85-90 | 4-6 months |
| Turnips | 32 | 90-95 | 4-5 months |
| Winter squash | 50-55 | 70-75 | 3-6 months |
Here are some excellent links to instructions on building several different types of root cellars, both in the house and outside of it. Some of the PDFs include vegetable storage guidelines as well.
Constructing and Using Root Cellars
Vegetable Storage in Root Cellars
Handbook for Building a Root Cellar