SECTION XL. SWEET POTATOES
The roots of sweet potatoes are put on the market in various forms. Aside from the form in which they are ordinarily sold, some potatoes are dried and then ground into flour, some are canned, some are used to make starch, some furnish a kind of sugar called glucose, and some are even used to make alcohol.
Fig. 203. Sweet Potatoes
The fact that there are over eighty varieties of potatoes shows the popularity of the plant. Now it is evident that all of these varieties cannot be equally desirable. Hence the wise grower will select his varieties with prudent forethought. He should study his market, his soil, and his seed (see Section XVIII).
Four months of mild weather, months free from frost and cold winds, are necessary for the growing of sweet potatoes. In a mild climate almost any loose, well-drained soil will produce them. A light, sandy loam, however, gives a cleaner potato and one, therefore, that sells better.
The sweet potato draws potash, nitrogen, and phosphoric acid from the soil, but in applying these as fertilizers the grower must study and know his own soil. If he does not he may waste both money and plant food by the addition of elements already present in sufficient quantity in the soil. The only way to come to reliable conclusions as to the needs of the soil is to try two or three different kinds of fertilizers on plats of the same soil, during the same season, and notice the resulting crop of potatoes.
Sweet potatoes will do well after almost any of the usual field crops. This caution, however, should be borne in mind. Potatoes should not follow a sod. This is because sods are often thick with cutworms, one of the serious enemies of the potato.
It is needless to say that the ground must be kept clean by thorough cultivation until the vines take full possession of the field.
In harvesting, extreme care should be used to avoid cutting and bruising the potato, since bruises are as dangerous to a sweet potato as to an apple, and render decay almost a certainty. Lay aside all bruised potatoes for immediate use.
For shipment the potatoes should be graded and packed with care. An extra outlay of fifty cents a barrel often brings a return of a dollar a barrel in the market. One fact often neglected by Southern growers who raise potatoes for a Northern market is that the Northern markets demand a potato that will cook dry and mealy, and that they will not accept the juicy, sugary potato so popular in the South.
The storage of sweet potatoes presents difficulties owing to their great tendency to decay under the influence of the ever-present fungi and bacteria. This tendency can be met by preventing bruises and by keeping the bin free from rotting potatoes. The potatoes should be cleaned, and after the moisture has been dried off they should be stored in a dry, warm place.
The sweet-potato vine makes a fair quality of hay and with proper precaution may be used for ensilage. Small, defective, unsalable potatoes are rich in sugar and starch and are therefore good stock food. Since they contain so much water they must be used only as an aid to other diet.