Small Acreage: The magnificent potato |

Small Acreage: The magnificent potato

Anne Wuerslin
CSU Extension Master Gardener in Larimer County

A Colorado-grown potato has a lot going for it.

With its historic heritage, it can claim distant pedigree to ancient cultivation centuries ago in the Andean Mountains to current development of cultivars which may prove to be the new superfood of our era, A.K.A. the “Super Spud”. It may not be a pretty vegetable, but it packs a nutritional punch. A lot of what is new and happening is right underfoot.

The potato (Solarum tuberosum) is perhaps America’s favorite vegetable, and ranks behind rice, wheat and maize as the world’s largest food crop. Idaho, Washington, Wisconsin, Oregon and North Dakota are big commercial producers of potatoes, with Colorado ranking fifth or sixth depending on the year.

The Front Range was once home to extensive potato production, but now the San Luis Valley produces about 90 percent of Colorado’s potatoes. In 1910 the USDA began their potato breeding program and today, the Colorado Potato Breeding and Selection Program, located near the San Dunes National Monument in southern Colorado, boasts an established research faculty dedicated to the development of new cultivars.

The high altitude of the valley with sandy loamy soil, adequate ground water, and abundant sunshine make it an ideal place for growing this tuber. The program looks to improve yield, quality, promote early maturity, raise potatoes which are resistant to disease and pests, and have good storability.

All of the above attributes can be applied to the home grown potato. As a warm season herbaceous perennial, potatoes are relatively easy to grow. Requirements include space, enough sunlight (at least 6 hours a day), and organically enriched soil.

Potatoes prefer acid soil with a pH or 4.8-5.5 but can tolerate alkalinity. Soils types may vary as well, with some potato cultivars that thrive in clay.

Soil temperature is very important. The ground temperature should be at least 50 degrees and not less than 40 degrees, which means that early maturing varieties can be planted 4-6 weeks before the last frost. For our area, this means late April to early May. Try not to plant potatoes in areas where tomatoes and eggplants have been raised to prevent soil borne pathogens.

Potatoes are usually grown from tubers and pieces of tubers. Use certified seed potatoes from a nursery or mail order company; do not use store bought potatoes which have been treated to prevent sprouting.

You can get a head start on sprouting potatoes by chitting—cutting tubers into seed pieces with one or two eyes or sprouts each. Allow the cut pieces to air dry or place in indirect light in a cool environment and allow them to sprout before planting. Planting too soon in wet, cold soil will cause rot. Alternatively, black plastic can be used to warm the soil before planting. Late frost may blacken plants but often the root stem will recover.

Potatoes are underground tubers which emerge from stolons. Recommendations for planting room suggest each row to be 12 inches wide and at least 4 inches deep. Rows should be 2 feet apart. Several methods include trench, trench with straw overlay and simply planting on the surface.

As the plants emerge, some of the tubers may find their way to the surface, causing greening of the potato and the production of solanine, which is toxic in large amounts. To prevent this, drag soil from between the rows and “hill up” at the base of the plant every two weeks. If you’re using straw, just add another layer of as the plant emerges. The straw will be mulch and help conserve soil moisture.

Cultivars (cultivated varieties) of potatoes are early maturing (60 days) midseason (80 days) and late season (90 days). Green plants usually emerge about 2 weeks after planting. For our area, use early maturing varieties. Try to find cultivars which may be fun and different such as specialty varieties (fingerlings, purples).

If space is at a premium, consider planting potatoes in old barrels, the compost pile, or in stacks of old tires with soil in the center. You can plant crop of cool veggies where your spuds once grew following your summer harvest.

During the growing season, water potatoes at the base and avoid overhead spray. In addition, do not work the soil around the plants when it is wet. Local pests include the Colorado potato beetle (relatively rare for our state despite its name), leaf hopper, aphids and flea beetles. Other diseases include blight, scab, viruses and nematodes.

There is nothing like digging potatoes and the process is wonderful for children as well.

By August, your early maturing harvest should be ready. Leaves will start to yellow and wither. Harvest with a pitchfork to prevent skin damage.

Or, lift your straw mulch and scoop away. Your efforts will be well rewarded at the dinner table. Many potatoes have a high satiety index.

An average potato is 110 calories, and is fat, salt and cholesterol free. It has more potassium (skin on) than a banana, and is rich in vitamins C and B4. It has iron, zinc and is a great source of fiber.

Most encouraging are some of the new cultivars developed in Colorado. Purple Majesty (2005), a purple flesh and purple skinned cultivar, has high levels of anthocyanidins which are antioxidants. The Rio Grande Russett is under investigation for its anti-cancer qualities.

Who knows what other goodness will be “unearthed” in the future? ❖

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