The key to winter vegetable storage is to understand what causes the wilting (or “senescence”) of harvested plants and slow or actively reverse that process. Wilting occurs when transpiration is occurring at a faster rate than water uptake. Thus, to preserve harvested vegetables we must ensure that the plants are continuing to take up moisture and effectively slow transpiration.
The most effective way to regulate transpiration is by dropping temperatures. As temperatures drop, molecules move at a slower rate, slowing gaseous release. Additionally, we must provide a moist environment for vegetables by providing a humid storage enviornment.
Across the country, achieving cool winter storage conditions is not particularly difficult. Here in Southern California, however, we must create that environment with what we have available. The most effective method is the crisper boxes in refrigerators. These boxes typically have a control for humidity and occasionally a separate temperature gauge so you can create a precise climate for your produce.
Before listing storage methods for different vegetables, it is important to note that many of winter crops can be frozen, such as:
- beets (cook, peel, remove stem and root tip, and cut into cubes)
- beet greens
- Brussels sprouts
- cabbage (cut into smaller pieces)
- carrots (blanch and peel first)
- mustard greens
- rutabaga (cook and cube first)
- turnips (cook and cube first)
Freezing hypothetically can store foods indefinitely, although we recommend consuming them within a year. It is also important to note that radishes and lettuce are not included in the list above. We don’t advise freezing either crop.
Below is a table created by H.C. Harrison, a professor of Agriculture at University of Wisconsin, that displays the relative humidity and temperature that various crops should be stored. By scanning the table, you can already get a sense for which crops can be stored together.
In Part 2 of this post, I’ll provide a crop-by-crop breakdown of proper storage techniques. Stay tuned!