Potatoes grown for winter use should be harvested after the vines have died and the crop is mature. To check maturity, dig up one or two hills of potatoes. If the skins on the tubers are thin and rub off easily, the crop is not fully mature and will not store well. Wait a few more days before harvesting. The skins on mature potatoes remain firmly attached to the tubers. When harvesting potatoes, avoid bruising, skinning, or cutting the tubers. Damaged potatoes should be used as soon as possible.
Before placing the potatoes in storage, the tubers should be cured. Cure potatoes at a temperature of 45 to 60 F and high relative humidity (85 to 95 percent) for two weeks. Healing of minor cuts and bruises and thickening of the skin occurs during the curing process.
Once cured, sort through the potatoes and discard any soft, shriveled, or blemished tubers. These potatoes may spoil in storage and destroy much of the crop. Potatoes should be stored at a temperature of 40 to 45 F and relative humidity of 90 percent. Store in a dark location as potatoes turn green when exposed to light. If storage temperatures are above 45 F, the potatoes will start to sprout after two or three months. When stored below 40 F, potatoes develop a sugary, sweet taste. Sugary potatoes may be restored to their natural flavor by placing them at room temperature for a few days prior to use. Do not allow potatoes to freeze.
Most modern homes have few good storage places for vegetables. A cool garage or basement may be the best site. Another possibility would be a second refrigerator. Do not store potatoes with apples or other fruit. Apples and other fruit give off ethylene gas which may promote sprouting of potatoes.
Green tubers are caused by exposure to light while in the garden or during storage. The green tissue contains glycoalkaloids which give the affected areas a bitter taste and can make one ill if eaten. When preparing potatoes, green areas should be cut away and discarded.
This article originally appeared in the August 11, 2000 issue, p. 101.