by Lis Friemoth

1 potato, 2 potato ...

While no longer used to predict the weather or deduce truth, potatoes remain a food staple around the world.

Originally found and cultivated in the Andean mountain range in South America, many varieties of the potato traveled back to Europe with the early Spanish explorers. As European explorers ventured into other regions of the world, potatoes traveled with them. As members of the Solonaceae family, potatoes are in good company alongside tomatoes, eggplants, and — yes — even nightshade.

They are relatively easy to grow, yield good-sized crops with moderate inputs, and despite many misconceptions, have excellent value as a food crop and low incidence of toxin issues.

A medium-sized potato has only about 100 calories and does not contain any fat or cholesterol, has more potassium than a banana, provides half the daily requirement of iron and 45 percent of the daily requirement of vitamin C, is low in sodium, and has loads of digestible protein.

Glycoalkaloid, also known as solanin, occurs when the tubers are exposed to light, either during the growth phase or if they’re not stored post-harvest under conditions of suitable darkness. It can be a fatal substance when ingested in huge quantities, although that is extremely rare.

In both instances, the skins of the tubers react to that light by turning green. Complete removal of these green areas will remove toxins from the tubers making them completely edible, although the quality will not be as good as those unaffected.

Potatoes can be grown from a seed (not usually) or a piece of tuber (seed potato), with the above-ground stem arising to produce the leaves and flowers that provide the carbohydrates for growth of the true roots, as well as the underground stems producing the edible tubers portion we call the potato.

The soil preference is a loose, well-drained loam to slightly sandy composition with a pH between 5 and 7. High organic content is a bonus. Clay or waterlogged soils will need vast improvements to get good potato production. You may want to consider raised beds or container plantings in the interim. Water should be adequate to ensure good tuber size. For a 100-foot row, expect to use about 10 pounds of quality, certified seed potatoes.

There are so many potatoes to choose from: early, mid late, fingerlings. Russets have reddish-brown skin with white flesh and a high starch content. Whites have smooth, whitish skins and white flesh with lower starch content. Reds have red, smooth skin with white flesh and are often the lowest starch content. Yellows have smooth, yellow skin with a yellow, creamy textured flesh. Blue/purples are showy with deep blue or purple skin with like-colored flesh that lightens somewhat during the cooking process. Fingerlings, which have a narrow elongated shape, have a smooth skin with waxy, yellowish flesh and the red crescent has a red heart..”

When choosing seed potatoes, look for firm flesh and healthy eyes (the indentations on the outside of the tuber). Most of the time, home gardeners will buy seed potatoes at the almost-full-grown size you can expect for the chosen variety.

You can begin the sprouting process by placing the seed potatoes in a single layer in a box in an area that gets a bit of light. Turn them periodically for uniform light exposure. This will force the eyes into sprouting prior to planting.

Whether the eyes are pre-sprouted or not, cut seed tubers into at least two-ounce chunks with two to three eyes per seed piece. This should not be done more than a day or two in advance of planting into the prepared soil.

About three to four weeks before last hard frost, potatoes can be planted if the soil is prepped and ready, although they will not begin to actively grow until the soil temperature reaches 45°F.

Rotate all Solanaceae crops so that they are not planted in the same area for three to four years to limit disease pressures.

Plant seed potatoes from 4 inches to 6 inches deep and cover with a couple inches of soil. My grandma had a great system for planting that was efficient and kept me (young, energetic, and annoying) occupied in the garden. She would mark off the row, then begin at one end with a hoe and an apron filled with cut seed potatoes. Walking from one end to the other, she would dig a hole, and I would have to promptly drop a potato in — eyes up. She would then dig the next hole, with that soil going to cover the previously placed potato. It was efficient and it kept me on my toes and paying attention, because I was not going to be responsible for an empty row that should have potatoes growing in it.

Spacing between plants should be about 9 to 12 inches, with rows about 2-1/2 feet apart if you are hand cultivating. If using equipment for weed control, space rows at about five feet apart. Be careful in weed control — the roots are voracious spreaders and must be allowed space to expand for optimum tuber growth. Shallow hand and mechanical tilling are best.

When stems reach about 6 inches to 8 inches tall, it is time to begin hilling around the potatoes. This serves a couple valuable purposes. One is to restrict light to prevent the development of the alkaloid toxins previously mentioned. The second is to provide a nice, loose soil area in which the tubers can develop. And because all tuber development occurs between the above-ground stem and the planted seed potato, this area is extremely important. Hill again about two weeks later. Expect to hill the potatoes about three times during the growing season, never covering more than the bottom third of the plant with each hilling.

Questions about fertilizing always arise. It is difficult to know what to apply unless you know where you are starting from. Get a soil test. In general, using an appropriate formulation based on soil-test results, fertilizer should be applied a couple of weeks prior to planting and at a depth that will ensure no contact with the tubers.

Once the stems reach about 8 inches in height, another application can be made. Rates are important, since too much will cause fast growth, producing weak stems. Timing is important as well. If applied too close to flowering, excessive vegetative growth will inhibit tuber development and growth. If applied too close to harvest, weak tuber tissue and disease can result.

Alternate methods of planting can be fun to try and rewarding in production. One way is to use mulch as a cover rather than soil. Plant the seed potatoes a few inches under soil level or lay on top of soil and cover with a nice loose mulch material, continue to cover as top grows, covering only the bottom third at a time. Remove mulch cover for harvest.

Another method is to plant in containers. Plant in clean, sanitized containers or use fencing to build an area for plant growth. Just be sure to allow for material to be easily added from the top or sides. Either soil or mulch (or a mix) can be used as a growing medium.

For both of these methods, monitor water needs closely because the loose material and exposed-side areas will use moisture at a quicker rate than traditional planting.

When growing conditions and plant health are good, a harvest of about 150 pounds per 100-foot row can be expected.

— Lis Friemoth is a horticulture diagnostician. Contact her at (262) 745-2904, P.O. Box 58, Springfield, WI 53176, visit online at www.thegardenhoe.com or e-mail her at gardenhoe@tds.net. Listen to Liz from 9 a.m. to 10 a.m. every third Saturday on WISN AM1130 radio.

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