This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
In the spring the ground should be thoroughly disked and harrowed, making a fine, firm seed bed.
Small acreages (five acres or less) of potatoes may be planted by hand if a horse planter is not available. Good potatoes have been raised by dropping them in every third furrow when plowing the field, letting the next furrow cover the seed to the depth of four to six inches.
Any larger acreage of potatoes, either on one farm or in a neighborhood, is best planted with a modern planter. With any of the standard two-horse planters five or six acres a day can be planted. In many places in the West potatoes are planted one piece in a place in rows thirty-six inches apart, and the pieces dropped eight to fourteen inches apart in the row. Planted twelve inches apart in the row makes 14,500 hills to the acre. If conditions were perfect, and each hill produced ten marketable potatoes weighing ten ounces each, a yield of nearly 1,500 bushes per acre would be secured. This is entirely possible. Fifteen years ago R. A. Chisholm of Del Norte, Col., grew 847 bushes to the acre, winning a gold purse offered by the Orange Judd Farmer for the best measured acre of potatoes in the United States.
Potatoes that are infected with any disease should never be used for seed. They frequently are, however - often when the grower is not aware of their presence. When disease is present, it can be carried from a diseased potato to a healthy one by contact in the bin, in the sack or in a planter. The knife used in cutting seed pieces is capable of spreading a disease throughout an entire lot of seed, and the "picker" on a picker planter may do the same thing. Disinfecting potatoes, as indicated in the chapter on diseases, is a good practice for skin diseases, but does not kill internal germ disease.
In southern Idaho potatoes are planted from May 1st to July 1st. Some early potatoes are planted as soon as April 1st. If these escape the late frosts they make big money, generally selling locally at from three to five cents a pound. If the frost catches them the ground may be planted to a later crop, so that some gamble on a few early potatoes to the extent of the price of seed and labor. There is always a possibility of a killing frost during the first two weeks of April.
From May 10th to June 10th is generally considered the best time to plant the main crop of late potatoes in the inter-mountain West.
With the horse planters a furrow two to four inches deep is opened by a pair of disks, and a ridge about two inches higher than the level of the field is turned up, putting the seed piece under about four to six inches of earth.
The amount of seed used by different potato growers varies from 600 to 3,000 pounds per acre. The growers who get the biggest yields plant the most seed. The largest crop ever grown in the country was with whole seed, using nearly 3,000 pounds per acre. Good yields are secured by using seed cut in two to four ounce pieces and having one to two eyes. Commercial seed potatoes weigh from two to ten ounces. The small seed is not cut the larger generally cut about four times. These work well in the planter and contain sufficient reserve nourishment to give the plant a good start. It is important that any plant to give the best returns in yield should start strong and vigorous. When potatoes are planted twelve inches apart in the row with rows three feet apart, if a perfect stand is secured and four ounce seed used, 3,630 pounds of seed per acre is required. With smaller seed and an ordinary stand, which is far from perfect, about 1,200 to 1,500 pounds of seed is used. The big seed starts a plant capable of making a big root system. The size of the root system bears a close relation to yield. With a large number of roots in the feeding area the greatest possible amount of food can be secured by the plant. Extremely large yields are secured by close planting.
Lawrence G. Dodge, in "Bulletin 365 on "Farm Management in Northern Potato Growing Sections," says:
The general methods of potato culture in use have developed during the past fifteen years, or a little more, and are followed with considerable uniformity throughout the section. The rotation is a simple one, but is undoubtedly the foundation of the success of the growers. Potatoes are grown on any piece of land only one year as a rule and are followed by one crop of oats or spring wheat, with which are sown clover and timothy for hay. This crop is cut for hay one year by many of the best farmers and plowed in the fall for a new potato crop. The furrow is usually turned to a depth of seven or eight inches, and on most of the farms this work is done with a reversible sulky plow, an implement admirably adapted to working on side hills. Some growers like their hayfields to stand a second year before plowing, but rarely longer than that, for the land is in too much demand for potatoes to continue it in grass more than two years.
The sod, usually containing a large amount of clover which was plowed the previous fall, is harrowed in the spring as soon as the season permits, usually being worked over thoroughly four times in all with a disk harrow followed by a spring-tooth harrow.
Planting is done from the 15th or 20th of May to the 1st of June, using about five barrels of seed to the acre - that is, thirteen or fourteen bushels. The seed is cut by hand into pieces containing about two eyes and of such a size as to feed readily through a planter, and is dropped by the planter in rows about thirty-three inches apart and from twelve to fifteen inches apart in the row, so that the ground is entirely occupied with the crop, and the vines in midseason meet in the rows.
There are two prevailing types of planter, in one of which the seed pieces are distributed by steel forks or pickers, and in the other by pockets in a revolving disk. Both types are two-horse machines, the former being operated by one man and the latter requiring a second man to attend to the seed distribution. Either type will plant about five acres per day. The planter at the same time distributes the fertilizer, from 1,200 to 1,500 pounds per acre usually being applied. This amount of fertilizer can be safely used directly in the drills. The fertilizer commonly used contains about 3 per cent, of nitrogen, 7 or 8 per cent, of phosphoric acid, and 9 or 10 per cent, of potash."