62 Modern Business Geography How the winter market of the United States is supplied with fresh vegetables. Now that freight cars can be heated in cold weather and refrigerated in warm weather, all kinds of fresh vegetables can be carried long distances without spoiling. Accordingly, the south- eastern quarter of the United States now ranks second only to the northeastern quarter in vegetable farming. The mild climate makes it profitable to raise vegetables in great quantities, even though the soil must be constantly fertilized and the northern markets are a thousand miles away. This is profitable because of the fancy prices obtained for southern vegetables from late fall to early spring, a period when their only rivals are greenhouse products. Thus even in midwinter almost any vegetable can be obtained in the great cities of the northeastern quarter of the United States. California competes with the South in supplying vegetables to northern markets in the late fall, winter, and early spring. Let- tuce, celery, asparagus, and many other vegetables from California regularly appear in eastern markets as soon as fancy prices prevail. A careful study of methods of packing for long transportation has been made, and as a result the vegetable farms in the vicinity of San Francisco and Los Angeles have become remarkably profitable. Potatoes. At the head of the list of our American vegetables stand potatoes. They are nearly twice as important as all the others combined. You can readily see why this is so when you recall that potatoes probably find a place on our dining tables more often than any other staple food except bread. The states of Minnesota, New York, Michigan, Wisconsin, Pennsyl- vania, and Maine are the greatest potato producers. Certain parts of those states, where the climate is cool and moist and the soil sandy, are especially adapted to potatoes. Under such conditions they yield a profit even when transported long distances, whereas in most re- gions it does not pay to raise them for any except the local market. In the South potatoes require more fertilizer than in the North, and the crop is far less abundant; yet because of the high prices com- manded by the first new potatoes in the spring, a good many are raised. Aroostook County in the northern part of Maine is by far the best potato region in the whole United States. More than two hundred bushels per acre are produced, which is twice as much as in most of the other parts of the country. | In European regions having cool, moist climates, potatoes are often grown in sandy soil that is infertile for most crops. The potato