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.
The following description of Oregon conditions is by Prof. H. D. Scudder, Professor of Agronomy in the Oregon Agricultural College at Corvallis:
The length of our growing season for potatoes is about seven months. Potatoes are generally planted the first two weeks in April and harvest is completed during the month of October.
The soils most commonly used for the potato crop here are sandy loams along the river bottoms and silt loams on the valley floor and on the hillsides. Both these types of soil produce a very fine quality of potatoes and, where properly handled, nearly the same yields, the sandy loams, of course, maturing the potatoes earlier and giving a larger yield if anything, as a rule. The silt loams, on the other hand, especially on the red hill lands, produce a very fine quality of potato.
The chief potato district in the state is the Willamette Valley, especially at its lower or northern end. The Umpqua Valley and the Rogue River Valley also are potato-growing districts, although of lesser importance.
All our potato seed is home-grown. The chief varieties are the Burbank and American Wonder, which are grown as table varieties, and the Early Rose, which is grown as a seed potato and shipped to California. The Garnet and Peerless are also grown to a lesser extent for the same purpose as the Early Rose.
The preparation of the land here generally consists in early spring plowing, harrowing and disking, then seeding immediately to the potatoes. On the smaller fields the potatoes are generally planted by hand and covered by the plow or with the hoe. In all the fields of any size, however, the planting is done with a planting machine. The more careless farmers give but little cultivation to the potato crop, sometimes merely harrowing the land a couple of times before the potatoes are up. The more successful growers, however, not only harrow the potatoes two or three times before they are up, using the weeder after they are up, but then use a row cultivator two or three times to complete the cultivation. Where such thorough cultivation is given the most excellent results are obtained.
Irrigation is not required at all for potatoes in western Oregon. They are never irrigated in the Willamette Valley at the present time, although in years to come there is no doubt that the yield may be slightly increased by irrigation when more intensive farming methods require the highest yields obtainable. In the Rogue River Valley the potatoes are sometimes irrigated, but this is not the common practice. Of course, in eastern Oregon wherever potatoes are grown on a commercial scale, at least, irrigation is used, as a rule. Potatoes in eastern Oregon, however, are grown only, as a rule, in amounts sufficient to supply the local markets. On the dry-farming wheat land in eastern Oregon the farmers are just beginning to produce potatoes for home consumption, and they are obtaining very fair yields of very high quality tubers. In fact, potatoes, grown under dry-farming conditions in eastern Oregon on the silt loams, or volcanic ash soils, as they are called, I believe to be the finest flavored and finest quality that I have ever seen.
Potatoes are harvested in all the large commercial fields by a machine digger, in the smaller fields by hand with the spade, or sometimes merely by plowing them up. Those potatoes which are stored are often merely dumped in bins in an ordinary warehouse, but the best growers, in those cases where they make a practice of storing them, are putting up specially constructed warehouses which are properly insulated with sawdust in the walls and with special ventilation to keep the potatoes in the best possible shape over winter. Practically no protection is required here against freezing, as that rarely occurs with our mild climate. What protection is used is generally merely to maintain equable temperature and humidity.
The Oregon potato crop is practically all marketed at Portland, Seattle, and San Francisco, all the Early Rose and other varieties raised as a seed crop, being marketed in the last city.
The cost of growing, of course, varies a great deal, but under good methods it will average from twelve to fifteen cents per bushel in the bin, this figure including interest on the investment. The profit, where the potato crop is grown as a regular part of the rotation, will average $40 or $50 per acre net.
No artificial fertilizers are used, the only fertilizer of any kind so far used or recommended being a cover crop of vetch and rye or vetch and oats sown in the fall and plowed under when twelve or twenty inches high early in the spring. The vetch, on account of its very high nitrogen content and nitrogen gathering ability, makes, of course, a wonderfully good covering and green manuring crop.
The size of the farms on which potatoes are grown in Oregon is about 100 acres, and the potato field is anywhere from five to sixty acres in size. A ten-acre field is generally considered a pretty good size field of potatoes, and forty or fifty acre potato fields are only had by those growers who are making a speciality of this product.
The big growers are beginning to use system in the culture and marketing of this crop, as well as using rotations which will keep the ground in the best condition. One of our best growers is using that old and everywhere very successful rotation of clover, followed by potatoes, followed by wheat, the first crop of clover being cut and left on the ground, and the second crop harvested for seed, the field being plowed early in the spring for potatoes. There are other rotations equally as good, but there are no special ones that have as yet been widely adopted.
Altogether, potato growing in Oregon is a very profitable industry, especially so where modern methods are employed and rotations are used. Year in and year out the market is high when compared with the potato market elsewhere and as yet no such thing as a potato disease or insect pest is known. As time goes on I think this crop will be more widely and intensively grown and one which will always prove excellent for including in rotations throughout Oregon."