The principles involved in the storing of perishable products, as fruits and vegetables, differ with the different commodities. All the root-crops, and most fruits, need to be kept in a cool, moist, and uniform temperature if they are to be preserved a great length of time. Squashes, sweet-potatoes, and some other things need to be kept in an intermediate and what might be called a high temperature; and the atmosphere should be drier than for most other products. The low temperature has the effect of arresting decomposition and the work of fungi and bacteria. The moist atmosphere has the effect of preventing too great evaporation and the consequent shriveling.
[Illustration: Fig. 187. The old-fashioned "outdoor cellar," still a very useful and convenient storage place.]
In the storing of any commodity, it is very important that the product is in proper condition for keeping. Discard all specimens that are bruised or are likely to decay. Much of the decay of fruits and vegetables in storage is not the fault of the storage process, but is really the work of diseases with which the materials are infected before they are put into storage. For example, if potatoes and cabbages are affected with the rot, it is practically impossible to keep them any length of time.
Apples, winter pears, and all roots, should be kept at a temperature somewhat near the freezing point. It should not rise above 40 F. for best results. Apples can be kept even at one or two degrees below the freezing point if the temperature is uniform. Cellars in which there are heaters are likely to be too dry and the temperature too high. In such places it is well to keep fresh vegetables and fruits in tight receptacles, and pack the roots in sand or moss in order to prevent shriveling. In these places, apples usually keep better if headed up in barrels than if kept on racks or shelves. In moist and cool cellars, however, it is preferable for the home supply to place them on shelves, not piling them more than five or six inches deep, for then they can be sorted over as occasion requires. In case of fruits, be sure that the specimens are not over-ripe when placed in storage. If apples are allowed to lie in the sun for a few days before being packed, they will ripen so much that it is very difficult to keep them.
[Illustration: Fig. 188. Lean-to fruit cellar, covered with earth. The roof should be of cement or stone slabs. Provide a ventilator.]
Cabbages should be kept at a low and uniform temperature, and water should be drained away from them. They are stored in many ways in the field, but success depends so much on the season, particular variety, ripeness, and the freedom from injuries by fungi and insects, that uniform results are rarely secured by any one method. The best results are to be expected when they can be kept in a house built for the purpose, in which the temperature is uniform and the air fairly moist. When stored out of doors, they are likely to freeze and thaw alternately; and if the water runs into the heads, mischief results. Sometimes they are easily stored by being piled into a conical heap on well-drained soil and covered with dry straw, and the straw covered with boards. It does not matter if they are frosted, provided they do not thaw out frequently. Sometimes cabbages are laid head down in a shallow furrow plowed in well-drained land, and over them is thrown straw, the stumps being allowed to project through the cover. It is only in winters of rather uniform temperature that good results are to be expected from such methods. These are some of the main considerations involved in the storing of such things as cabbage; the subject is mentioned again in the discussion of cabbage in Chapter X.
In the storing of all products, especially those which have soft and green matter, as cabbages, it is well to provide against the heating of the produce. If the things are buried out of doors, it is important to put on a very light cover at first so that the heat may escape. Cover them gradually as the cold weather comes on. This is important with all vegetables that are placed in pits, as potatoes, beets, and the like. If covered deeply at once, they are likely to heat and rot. All pits made out of doors should be on well-drained and preferably sandy land.
When vegetables are wanted at intervals during the winter from pits, it is well to make compartment pits, each compartment holding a wagon load or whatever quantity will be likely to be wanted at each time. These pits are sunk in well-drained land, and between each of the two pits is left a wall of earth about a foot thick. One pit can then be emptied in cold weather without interfering with the others.
An outside cellar is better than a house cellar in which there is a heater, but it is not so handy. If it is near the house, it need not be inconvenient, however. A house is usually healthier if the cellar is not used for storage. House cellars used for storage should have a ventilating shaft.
Some of the principles involved in an ice-cooled storage house are explained in the diagram, Fig. 189. If the reader desires to make a careful study of storage and storage structures, he should consult cyclopedias and special articles.