If the land selected for potatoes is lacking in humus, fine compost or well-rotted manure will greatly increase the yield. However, it should be remembered that green manure makes a good home for the growth of scab germs. Hence it is safest to apply this sort of manure in the fall, or, better still, use a heavy dressing of manure on the crop which the potatoes are to follow. Leguminous crops supply both humus and nitrogen and, at the same time, improve the subsoil. Therefore such crops are excellent to go immediately before potatoes. If land is well supplied with humus, commercial fertilizers are perhaps safer than manure, for when these fertilizers are used the amount of plant food is more easily regulated. Select a fertilizer that is rich in potash. For gardens unleached wood ashes make a valuable fertilizer because they supply potash. Early potatoes need more fertilization than do late ones. While potatoes do best on rich land, they should not be overfed, for a too heavy growth of foliage is likely to cause blight. Be careful to select seed from sound potatoes which are entirely free from scab. Get the kinds that thrive best in the section in which they are to be planted and which suit best the markets in which they are to be sold. Seed potatoes should be kept in a cool place so that they will not sprout before planting-time. As a rule consumers prefer a smooth, regularly shaped, shallow-eyed white or flesh-colored potato which is mealy when cooked. Therefore, select seed tubers with these qualities. It seems proved that when whole potatoes are used for seed the yield is larger than when sliced potatoes are planted. It is of course too costly to plant whole potatoes, but it is a good practice to cause the plants to thrive by planting large seed pieces. [Illustration: FIG. 205. GATHERING POTATOES] Like other crops, potatoes need a thoroughly prepared seed-bed and intelligent cultivation. Break the land deep. Then go over it with an ordinary harrow until all clods are broken and the soil is fine and well closed. The rows should be at least three feet from one another and the seeds placed from twelve to eighteen inches apart in the row, and covered to a depth of three or four inches. A late crop should be planted deeper than an early one. Before the plants come up it is well to go over the field once or twice with a harrow so as to kill all weeds. Do not fail to save moisture by frequent cultivation. After the plants start to grow, all cultivation should be shallow, for the roots feed near the surface and should not be broken. Cultivate as often as needed to keep down weeds and grass and to keep the ground fine. Allow potatoes to dry thoroughly before they are stored, but never allow them to remain long in the sunshine. Never dig them in damp weather, for the moisture clinging to them will cause them to rot. After the tubers are dry, store them in barrels or bins in a dry, cool, and dark place. Never allow them to freeze.