A Few Rows of Home Garden Potatoes Can Put Nutritious Food on Your Table

by Orrin C. Turnquist.

Orrin C. Turnquist is Professor and Extension Horticulturist, University of Minnesota, St. Paul.

The potato is probably the most important vegetable crop in the world today. None other is used as regularly and in such quantity in the average American home. Its culture is simple and it is a dependable and efficient food producer on any soil suitable for general garden crops.

Does the potato have a place in your home vegetable garden? The answer depends on the size of the garden.

On the average, a 100-foot row planted with 10 pounds of seed should yield between 1 and 2 bushels of potatoes. Obviously the 10 to 20 bushels a family of 5 might require for winter use would be difficult to produce in the small backyard garden. Yet, even in small gardens after space has been provided for such vegetables as tomatoes, green beans, and leafy greens the potato might be considered for planting on any remaining space.

Space-saving techniques such as intercropping can also be used in growing early potatoes in the small garden. Vining crops like cucumbers, melons and squash can be planted between rows of potatoes. After the early potatoes are harvested the area is free for the vine crops to spread and produce their crop.

The potato's home is in the mountainous regions of South America, although it is referred to as the Irish potato. It was cultivated rather extensively by the Inca Indians of Peru as far back as 200 A.D. Early explorers after Columbus introduced the Potato to Europe between 1532 and 1550.

Not until the potato was introduced into Ireland was it recognized for its great food value rather than as a curiosity, and by the 1600's it was cultivated extensively in that country. For approximately 250 years the potato was a major source of food in most of Europe. In fact the majority of the population in Ireland depended on this crop for its existence.

When the late blight disease came from America into Ireland (1845-1847) it caused a national disaster. Destruction of the vines and decay of the tubers caused a complete loss of the crop nationwide. The result was the Irish famine in which thousands starved to death.

A colony of Presbyterian Irish who settled in New Hampshire introduced the potato to our country in 1719. Soon after the Irish famine the potato gained in importance in the United States.

As late as 1771 only two varieties of potato were listed, but during the 19th century thousands of varieties were developed and introduced in America. Only a small number were accepted, however. Some varieties still prominent today originated during that period. They include Irish Cobbler (1875), Russet Burbank (1876), Green Mountain (1878), Red McClure (1880), and White Rose (1893).

The cultivated potato in North America and Europe is known botanically as Solanam tuberosum. It is a member of the nightshade family which includes such plants as tomato, egg plant, pepper, ground cherry, bittersweet, petunia and tobacco.

Although grown as an annual, it is often considered a perennial because of its ability to reproduce vegetatively by means of tubers that arise from underground stems. In fact the tubers have all the characteristics of normal stems, including dormant true buds which are called eyes and rudimentary leaf scars that are called eyebrows.

The small dots on the tubers are identical to lenticels on a stem which facilitate the exchange of gases. These lenticels often become enlarged and objectionable when tubers develop in soils with excessive moisture and access of air is restricted.

Contrary to much common opinion, development of tubers does not depend upon flowering. Potato plants will form tubers without any flower development on top. The fruits or seed balls that develop from the flowers on some varieties are true fruits. These berries are not edible. They are not the result of cross pollination with the tomato, as many gardeners believe.

Although some of these fruits are seedless, normally they contain many small true seeds, no two of which are alike. The fact that these true seeds will not be the same as the variety from which they came is the reason we do not grow potatoes from true seed. Instead we propagate the potato by stem cuttings called seed pieces or seed eyes. The use of true seed is impractical for all except potato breeders who control the pollination and use the resulting seed in development of new varieties.

The tubers usually initiate at the tips of the stolons (underground stems) from 5 to 7 weeks after planting or when the plants are 6 to 8 inches tall. This varies with the variety and several environmental factors. As the plant grows the leaves make food for continuing growth. A point is reached, however, where a supply of food is made beyond what is needed for growth. This is when excess food is moved down into tubers for storage.

Environmental factors such as long days, warm temperatures, high moisture and fertility tend to favor plant development whereas short days, cool temperatures, lower moisture, and less fertility promote tuber development. Don't forget that a good yield of potato tubers depends first of all upon a good healthy plant development.

Potatoes are grown from "seed pieces" or "seed eyes" that are a quarter cut of the potato and include a couple of "eyes."

Certified Seed

One of the most important steps to success in growing potatoes is the use of sound, healthy, certified seed. Potatoes are subject to several diseases whose symptoms are not easily recognized on either tubers or plants. Many are virus diseases that dwarf the plant and cut the yield in half. High-yielding seedstocks can be maintained only under carefully controlled conditions of isolation, disease control and storage.

Certified seed potatoes are grown mainly in the Northern States where lower growing temperatures favor the expression of virus disease symptoms so the infected plants can be eliminated. There are also fewer insects present that spread the diseases.

Home-produced potatoes may become infected in a single season, so there is no assurance that seed saved from a high yielding crop will perform satisfactorily the following year. It is best to buy new certified seed each year. Certified seed potatoes are usually identified by an official State Department of Agriculture tag on each bag. The higher cost of this seed is more than justified by the higher yield and better quality of the new crop.

Table stock potatoes that you buy at the food store should not be used for seed. They often have virus diseases present and may have been treated with a growth-inhibiting chemical to prevent them from sprouting in the market place.