Two kinds of storage are used, common or cellar storage and cold storage. Both are about equally available, but the latter is too expensive for the small grower. There is always a question as to the advisability of the small grower storing his fruit. Storage means a degree of speculation. "A bird in the hand is worth two in the bush," especially when the bird is a good one. So far as rules can be laid down, the following are pretty safe ones to keep in mind: It is safest to store apples when they are of the highest quality; in a season most unfavorable to common storage; when the fewest are being stored; when the price in the fall is medium to low, never when high; and when one can afford to lose the whole crop.
Successful storage requires several things: good fruit, stored immediately after picking, careful sorting and handling, subsequent rest, and a reasonable control of the temperature. The functions of storage are to arrest ripening, retard the development of disease, and furnish a uniform, cold temperature. Storage of apples does not remedy over-ripeness nor prevent deterioration of already diseased, bruised, or partly rotted fruit. There are three general methods of storage: (1) by ventilation, (2) by the use of ice and (3) by mechanical means.
Cooling by ventilation offers the most practical system for a farm storage. It requires that there be perfect insulation against outside temperature changes, adequate ventilation, and careful watching of temperatures. To provide for good insulation a dead air space is necessary. This can be secured by a course of good two-inch boards with one or two layers of building paper inside and out, over a framework of two-by-fours. Over the building paper tight, well matched siding should be laid also inside and out. Two of the dead air spaces will make insulation doubly sure.
To provide for proper ventilation construct an intake for cold air at the bottom, and an outlet for warm air at the top of the room. These should serve all parts of the room, one being necessary for this purpose every twelve to sixteen feet. Do not depend too much on windows. Warm-air flues should be twelve inches square and six to twelve feet long.
The attention to such a house is most important. Keep it closed tightly early in the fall with blinded windows. When nights get cool open the doors and windows to let in cold air, closing them again during the day. On hot days close the ventilators also. In this way a temperature of 36 to 40 degrees Fahr. can be secured in early fall and one of 32 to 33 degrees Fahr. later. This is probably the cheapest as well as the most practical method of farm storage.
Ice storage is quite practical in the North, but more expensive. The principle of such a storage is to keep ice above the fruit, allowing the cold air to flow down the sides of the room. A shaft in the middle of the room will serve to remove the warm air. This method is open to the objection of difficulty in storing the ice above the fruit. Moreover the uniformity of its cold air supply is questionable. Mechanical storage in which cold temperatures are secured by the compression or absorption of gases is altogether impracticable for individual growers, as it costs from $1.50 to $2.00 a barrel of capacity to construct such a storage. Rents of this kind of storage range from 10 to 25 cents a barrel per month, or 25 to 50 cents a barrel for the season of from four to six months.