The following is an excerpt from Preserving Food Without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation  by the Gardeners & Farmers of Terre Vivante . It has been adapted for the Web.
• Dried leaves
• Plastic sheeting
When the growing season is over and our sauerkraut pot is full, ripe cabbages often remain in the garden but cannot withstand the rigors of winter. To preserve this vegetable, we do the following:
In a dry, well-drained spot that is protected by a hedge or a wall (for example, at the end of a cold frame), dig a 16-inch-deep pit, with its width proportional to the quantity of cabbage to be preserved. Spread the soil and pack it all around the hole, to raise its sides.
Pick the cabbage and remove any leaves that are “too” green, bruised, or rotten. Place the cabbage plants in one layer at the bottom of the hole, roots facing up. Cover the cabbage with autumn leaves that are not too damp. Be careful not to pack them tightly. To protect from the rain, cover with a sheet of plastic or other waterresistant material.
About three to four months later, in early spring, we can once again prepare an excellent sauerkraut.
Beets, carrots, black radishes (with leaves removed), and even geranium plants and cuttings can be kept in the same manner. If different vegetables are to be stored together, they must be arranged such that they can be accessed conveniently without having to dismantle the entire silo. Be sure to reclose it each time.
Bernard Gabard, Péage-de-Roussillon