Storage temperatures should be from 50 to 60 degrees F, and the relative humidity at 60 percent. These are the best storage conditions for keeping pumpkins and winter squash together. Cure them first by exposing them to high temperatures, at least 80 degrees F, for a period of a week to 10 days before storage.
A temperature for the optimum preservation of most vegetables is 32 and about 40 degrees F. However, a few vegetables, like cured onions, need humidity around 65 percent, so they cannot be stored with humidity-loving vegetables.
Thirty-two to 40 degrees F and 95 percent humidity keeps potatoes, radishes, carrots, parsnips and beets at the height of their freshness for months at a time. Crate or stack like vegetables together, and check often to remove any bad ones. Since vegetables are about 95 percent water, they help keep one another moist. A small, packed cellar is more effective than a large, spacious one. Pungent vegetables, such as onions, garlic, cabbage and turnips, leach odors and tastes that are absorbed by milder-flavored vegetables like potatoes and parsnips. Avoid storing them together.
Fruits do not tolerate storage well. They cannot be stored with vegetables due to the ethylene gas they emit, which promotes rapid spoilage in vegetables. Tomatoes and cucumbers fall into this category and cannot be stored with vegetables.