Community A - L: Potatoes

Click here to view full size picturePotato growers today must have an in-depth understanding of potato plant physiology. Plant knowledge makes it possible for them to manipulate both environmental and physiological conditions. Climate, soil content and structure, altitude, latitude, length of growing season and geographic area are all variables that can either be manipulated or responded to in various ways in order to ensure a top-quality potato. Recognition of the considerable differences among potato cultivars in responding to each of these variables must also be taken into account. Growers must study and research all through the planting and growing process in order to get a high quality, high yielding potato crop.

Potatoes have come a long way from their origins in the small mountain fields of South America. Today, potatoes are grown all around the world, in more than 180 countries. Only corn grows in more places. Russia leads in potato production, growing about 33% of the world crop. Following Russia is Poland, the United States and either Canada or China.

Crop rotation is practiced in potato production. Potatoes are usually rotated with wheat, corn, and vegetable crops. Commercial fertilizers are worked into the soil in varying amounts per soil, climate and cultivar requirements. Most potato growers rotate their fields from year to year so the same field never has a potato crop two years in a row. When a field is planted into potatoes, potato growers use large mechanical planters that can plant several rows of high-quality seed potatoes at one time. Planting may take place as early as November or as late as June, depending on the climate or the region.

The seed potato or seed is dropped into a trough by a mechanical planter. Planting depth and spacing must be exactly determined as it varies from cultivar to cultivar, climate to climate. Soil analysis determines which fertilizers are necessary and in what amounts. Then fertilizer is deposited on either side of the potato and a hill of earth is made on top of the planted seeds or seed potatoes. Again, the depth of the seed or seed potato must be exactly determined. While the plant is growing, the field is monitored for diseases and pests. If they are found, measures are taken to control them. Chemicals can be sprayed on the fields by cropdusters, chemigated through the irrigation systems, or sprayed by machine.

The plants are killed when it's time for harvesting if they haven't died due to cold weather. This allows the tubers to mature and the skin to set so they will store well. It is easier for the harvesting machines to do their work when the plants are dead and dessicated. Many harvesting machines can pick up to eight rows of potatoes at a time. They cut off the vine, lift the potatoes out of the ground, separate the earth and stones from the potatoes and load the potatoes by conveyer belt into a truck.

History of the Potato
Potato Planting and Growing
Storage Information for Potato Growers
Potato Varieties
Potato Products
Storage Information for Consumers
Potato Recipes

History of the Potato

South American Potato History
A high plateau in the Andean Mountains of South America is the birthplace of the "Irish" white potato that we eat today. The plateau, known today as the Titicaca Plateau, stretches across part of the countries of Peru and Bolivia. The Aymara Indians developed more than two hundred varieties of the potato at elevations greater than 10,000 feet. Potatoes formed the basis of the Aymara Indian and Incan diet.

Potatoes also were an important influence on Incan culture. Potato shaped pottery complete with eyes are commonly found at excavated sites, sometimes having tiny heads growing out of the little eyes. Incan units of time correlated to the length of time it took for a potato to cook to various consistencies. Potatoes were even used to divine the truth and predict weather.

How the Potato got to Europe
When the Spanish Conquistadors didn't find the gold and silver they were looking for in the late 1400s and early 1500s, they quickly cornered the local potato market. Potatoes were soon a standard supply item on their ships. The Spanish noticed that the sailors who ate papas (potatoes) did not suffer from scurvy.

Potatoes Slowly Became Popular in Europe
No one knows exactly when potatoes were first planted in European soil. For many reasons, the potato was slow to become popular. At the time, only seed crops were grown in Europe, and this vegetable was planted by cutting it into pieces to put in the ground. The potato plant was also recognized to be a member of the nightshade family, a group of plants that are generally very poisonous. Amid fears of black magic and poisoning, it is thought that the first to cultivate potatoes were probably the families of the sailors who brought them back. By the late 1500s, historical records show that the potato began to be used as a common provision in some parts of Spain.

Potato cultivation
slowly spread to the low countries and Switzerland. When introduced into Germany in the 1620s, the nutritional properties of the potato were finally acknowledged. Frederick the Great, the Prussian ruler, ordered his people to plant and eat them as a deterrent to famine, a common and recurrent problem of that period. People's fear of poisoning led him to enforce his orders by threatening to cut off the nose and ears of those who refused. Not surprisingly, this was effective and by the time of the Seven Years War (1756 1763), potatoes were a basic part of the Prussian diet.

A similar story occurred in France. A young French agriculturist and chemist, Antoine Augustin Parmentier, made it his mission to popularize the potato after his experience as prisoner of war in Prussia. With some clever marketing to King Louis XVI and Marie Antoinette, and subtle scheming to convert the thinking of the populace, Parmentier achieved his goals. Potato dishes were created in great variety and the potato became a delicacy enjoyed by the nobility. The French populace soon coveted potatoes for themselves.

The Potato Becomes a Staple Food Crop
The potato quickly took the place of other crops as a food staple because it was a more reliable crop than wheat, which suffered as a food crop when the damp climates of Europe prevented proper ripening. Potatoes furthered both an agrarian revolution already underway in the early 17th century and a population increase in Europe in the 17th and 18th centuries. As a result, more and more farmers were drawn from subsistence farming into profit driven economies. The agrarian revolution, stimulated by the potato, was an integral stimulus to the Industrial Revolution.

European immigrants introduced potatoes to North America several times throughout the 1600s, but they were not widely grown for almost a century. Not until 1719, when Irish immigrants brought the potato to Londonderry, New Hampshire, were potatoes grown on a large scale. Again, potatoes were slow to gain popularity. Even when they became the second largest food crop in America, they were still used primarily as animal fodder.

The Irish Potato Famine
Ironically, the dependable potato was responsible for one of the most horrifying famines of the last 200 years. Introduced into Ireland in the mid 1700s, the potato proved to be an ideal crop for its environment. Ireland gets an average of 60 inches of precipitation each year, in general too much for potatoes. However, the precipitation is mostly in the form of soft misty showers, which keep the air cool and the soil moist.

By the 1800s, Irish peasants were eating a daily average of 10 potatoes per person. Potatoes supplied about 80 percent of the calories in their diet. The peasants used potato fodder to feed their animals, animals which provided milk, meat and eggs to supplement the peasants' diet. This dependence on one food crop was dangerous, but no other crop had ever proved to be as reliable.

In the 1840s, disaster struck. Three successive years of late blight, the microscopic fungus Phytophthora infestans, and heavy rains rotted the potato crops in the ground. Without potatoes, both the peasants and animals went hungry. And when the animals died for lack of food, milk, meat and eggs were no longer available. More than one million of Ireland's 8 million inhabitants died of starvation; almost 2 million emigrated. The population of Ireland was reduced by almost one fourth and has never regained its former numbers to this day.

We know now that genetic diversity might have mitigated this disaster, but this was not recognized at the time. Late blight and famine were not isolated to Ireland; the European continent was subjected to the same wet and cold weather and had the same poor crops. The new field of plant pathology was stimulated by these disasters. The German botanist Heinrich Anton de Bary published his findings on the complete life cycle of Phytophthora infestans in 1861. This was one of the first times that a fungus was identified as the cause of a plant disease. During the same period, people discovered several ways to control the disease, using lime in combination with either sulfur or copper sulfate, a Bordeaux mixture.

Today, scientists are constantly developing and studying new and different varieties to prevent a disaster like this from happening in Third World countries where the potato is, or could be, an important staple.

Luther Burbank
At the same time potatoes soared in popularity as a food staple in Europe, their popularity also grew in the U.S. Known as the Irish potato, the tuber was soon grown in every state in the Union.

Seeking to improve the "Irish potato", the self taught and brilliant American horticulturist Luther Burbank took the first step. Growing twenty three seedlings from an Early Rose parent, he discovered that one seedling produced two to three times more tubers of better size than any other potato variety he had yet grown. After testing this new variety, Burbank marketed the seedling he called the Burbank to the West Coast states in the late 1800s.

Cultivation of the Burbank spread throughout the Western States. Within a few short years, a mutation of the Burbank, which appeared to be more disease resistant, was discovered in Colorado. The mutation had rough, reticulated skin and was named the Russet Burbank. Today, several varieties of the Russet are some of the most popular.

Montcalm County Develops its Potato Industry
Montcalm countys's potato industry began in the late 1800s when Danish settlers moved into the Trufant area. These early settlers cleared the white pine stumps left from logging and established small farms each of which had a small acreage of potatoes. The fertile sandy soils and the favorable climate of the area were favorable for production of this crop. As growers moved to other areas of the county in search of land production increased rapidly in the county. Markets for these potatoes developed rapidly, and soon Greenville was one of the largest markets for fresh potatoes in the United States.

Potato Consumption
In the 1950s, potato consumption began to drop in the United States. It had risen steadily for over one hundred years, but tapered off with the advent of convenience foods and the mistaken idea that potatoes were fattening. In response, food researchers began looking at various ways of processing potatoes to make them more attractive and convenient for consumers. New techniques such as dehydro freezing (freeze drying), explosion puffing, and using infrared light to create a kind of seal on the tissue of the potato were developed. By the late 1950s, consumption was on the rise again. Today, more than half of all potatoes grown in the U.S. are used in the processing industry.

Potatoes are Grown all over the World
Today potatoes are grown all through the United States and in about 125 countries throughout the world.

Fun Facts and Trivia

  • The potato is about 80 percent water and 20 percent solids.

  • The world's largest potato chip was produced by the Pringle's Company in Jackson, TN in 1990. It measured 23" X 14.5"An 8 ounce baked or boiled potato has only about 100 calories.

  • The average American eats about 124 pounds of potatoes per year while Germans eat about twice as much.

  • In 1974, an Englishman named Eric Jenkins grew 370 pounds of potatoes from one plant.

  • Thomas Jefferson gets the credit for introducing "French fries" to America when he served them at a White House dinner.

  • The potato belongs to the family Solanaceae; all the plants in this family share certain characteristics, like having similar leaves and flowers. Other members of the family are the tomato, the chili pepper, the eggplant, poisonous nightshade, belladonna, the petunia, and the tobacco plant. Some parts of these plants are very poisonous.

  • Tomatoes, Batatas, Potatoes, Patatas. . .The sweet potato belongs in the same family as the morning glory (Ipomoea batatas)and is not a relative of the potato. The Spanish who brought sweet potatoes back from the West Indies called them by their native name batatas. When white potatoes (papas) were introduced into Spain some years later, some people thought they were related. Soon papas were renamed patatas, but both were translated into the English as potato. Let's call the whole thing off!

  • The potato skin changes its chemical structure after it is harvested. The outer layers thicken and harden, and their cells are converted to the same substance that is found in bottle cork.

  • Less than 1 acre of potatoes can produce enough potato gasahol to fill up 25 cars.

Potato Planting and Growing

Potato Planting and Growing

Storage Information for Potato Growers
There are more than 16,000 producers, packers, shippers, and processors of potatoes in the United States. Packers and shippers are responsible for storing the potatoes so that their quality remains as high as possible. Both retail customers and processors want a top quality potato that meets their needs.

Potatoes grown for potato chips are a very important source of agriculture revenue to the state of Michigan, and about two thirds of Michigan's potato crop is for potato chips. The value of production of chip potatoes was estimated at $62 million in 1967.

Potato processing contributes a huge amount of revenue to the United States economy. In the northwestern region of the U.S, almost $2 billion is contributed per year from value added frozen potato products. Washington, Oregon and Idaho lead the nation in the frozen potato market, producing 80% of the country's frozen French fries and hash brown potatoes. Potato processing is the Northwest's primary vegetable processing industry, employing more than 15,000 people on a full time, year round basis and many more seasonally. The food processing industry as a whole is the largest industrial employer in Idaho, and is second behind aerospace in Washington.

How well potatoes store and how they process when removed from storage depends largely upon the condition of the tubers going into storage. Growth, harvest conditions and tuber maturity are as influential as the actual storage process. Bruising is probably the single most important factor that reduces the financial returns of the potato industry.

Impacts of Growth Conditions on Tuber Storage
Potatoes grown under stress have uneven tuber growth. Stressful conditions such as temperature extremes, non uniform moisture, defoliation, nutrient imbalance, or inadequate or excess fertilizer result in tubers more prone to problems. Early stress, when plants are young and tubers are forming, is more serious than stress later on in the growing season. Manifestations of stress are, most commonly, malformed tubers, accumulation of sugars both in the field and in storage, development of sugar and jelly end tubers, and premature physiological aging and sprouting of tubers in storage.

Achieving tuber maturity is more complicated. As tubers grow, develop and mature, a peak in dry matter occurs. A minimum amount of sugars is achieved shortly thereafter. This is important because high dry matter and low sugar content are important for processing. This stage is considered physiological maturity and is an indicator of when to start vine kill and harvest.

When the skin has been set properly, which occurs along with physiologic maturity under non stress conditions, the potatoes will store well. But when stress conditions occur, physiologic maturity may occur without adequate skin set. Stress can also change physiologic maturity by continuing to mature tubers on plants that have already died, changing reducing sugar content, weight, etc. Storage of tubers that are immature and "skinned" results in a variety of problems. What is important to remember is that the maturation process will continue in storage; skins will continue to thicken and set.

Impacts of Harvest Conditions on Tuber Storage
Several criteria are considered in preparing to harvest and store potatoes. Vine kill must be carefully controlled. Rapid vine kill can cause stem end discoloration. Excess late fertilization interferes with vine and tuber maturation. Too much soil moisture can increase blackspot susceptibility; too little soil moisture can hinder rapidity and degree of skin set.

Growers try to harvest during optimum soil conditions. Soil should be lightly moist and soil and pulp temperatures should be between 45 and 60! F. Otherwise tuber bruising can result. Care is taken to avoid transporting soil into storage; excess soil in storage prevents good air circulation and increases susceptibility to rot.

When operating the harvester and piler, care is taken to reduce bouncing and rolling the tubers or bruising can result. When transporting the tubers from harvest to storage, care is taken to avoid wind and sun.

Storage of Tubers
Optimally, growers like to store only sound, unbruised tubers that have not been stressed during growth. Heat from the field must be removed quickly, preferably within three days. Removal of field heat is important as rapid wound healing is necessary. In addition, tuber maturation will occur for a month or more but only at temperatures of 50! F. with relative humidity above 95%.

After the wound healing period, the temperature is slowly lowered one half degree per day to the long term holding temperature. The growers goal is to prevent sprouting and maintain weight. Long term storage temperatures vary with the potato's future use, the variety, and the amount of bruising and rot that is present. Humidity levels are maintained at 95%.

Daily storage management now becomes extremely important. Proper ventilation and temperatures must be maintained and humidity and condensation monitored. But no machine can take the place of the human monitor. Smelling for rot and looking for condensation and wet tubers is still a necessary daily task.

Seed potatoes store best at 38 40! F. Physiologic aging and sprouting can be kept to a minimum at this temperature. Tubers stored at higher temperatures will loose weight.

Processing potatoes are stored at 45 47! F. If temperatures are lower, the tubers will accumulate sugars which results in dark fry color and poorer textures. Again tubers stored at higher temperatures will lose weight. Fresh market potatoes are stored at 43 45! F. to minimize weight loss and sprouting. Chip potatoes are stored at 50!F. to prevent starch to sugar conversion though some varieties can be stored at slightly lower temperatures.

Storage Rot
The biggest potential for tuber loss while in storage is storage rot. Most rot organisms are present in the field and only require bruises to enter the tuber. Tubers which have been subject to growth stress are much more susceptible.

Rot development in storage is normally very noticeable. Putrid odors, wet and slimy tubers, disintegration (from dry rot), and surface blemishes are all characteristics of rot. Soft rot is the most common storage rot.

Soft rot (Erwiniaspp.) spreads rapidly in the presence of free water on the surface of tubers. Infected areas are initially cream colored and later may become brown, producing slimy areas with a foul odor.

Fusarium dry rot (Fusariumspp.) takes several months to develop in storage. The organism enters through cuts and bruises. Infected areas will completely fall apart and disintegrate.

Pythium water rot (Pythiumspp.) infects tubers in the field. High storage temperatures and low storage humidity promote its development. It will affect isolated tubers throughout the pile.

Early blight tuber blemish (Alternia solani) enters the tuber through cuts and bruises. Shallow, necrotic sunken blemishes will appear after a period of storage.

Potato Varieties

Potato Varieties

Potato Products
There are more than 16,000 producers, packers, shippers, and processors of potatoes in the United States. Packers and shippers are responsible for storing the potatoes so that their quality remains as high as possible. Both retail customers and processors want a top-quality potato that meets their needs.

Potato processing contributes a huge amount of revenue to the economy. In the northwestern region of the U.S, almost $2 billion is contributed per year from value-added frozen potato products. Washington, Oregon and Idaho lead the nation in the frozen potato market, producing 80% of the country's frozen French fries and hash brown potatoes. There were 119 potato chip plants in all regions of the U.S. in 1997 that processed 47,528,000 cwt. of potatoes. If we figure it takes four pounds of raw potatoes to make one pound of potato chips, there were 11,882,000,000 pounds of chips made.

How well potatoes store and how they process when removed from storage depends largely upon the condition of the tubers going into storage. Growth, harvest conditions and tuber maturity are as influential as the actual storage process. Bruising is probably the single most important factor that reduces the financial returns of the potato industry.

Man has dehydrated potatoes for more than 1000 years. First the Inca Indians of the Andes created chuño, then the Spaniards carried the process back with them to Europe. Dried potatoes were used as staples and to create potato flour. During the Industrial Revolution, drying processes emerged in Germany and England. Production of potato starch and fried potato chips developed in the 1800's. Finally, both World Wars I and II resulted in the development of quick rehydrating dried mashed potatoes.

The era of convenience foods began after World War II. It escalated in the late 1950s and has led to the development of a world-wide market for a wide range of dehydrated and frozen potato products. Thanks to the processing industry, in the U.S. alone, annual consumption of processed potatoes is now at more than 140 pounds per person.

The most important product in the potato processing industry is the French fry. American soldiers were introduced to fried potatoes in Belgium during World War I. U.S. restaurants adopted the product and popularized it. But developing a frozen product for home use wasn't perfected until the 1950s. Then the Mac-fry process revolutionized the fast-food French fry business and French fries became a primary menu item. Today, more than 50% of the potatoes grown in the U.S. are destined for processing.

A processing potato must have a high specific gravity and a low sugar content. A high specific gravity is necessary because it indicates how much water must be evaporated from the potato during the dehydration process. It is actually a measure of the dry matter or "solids" in the potato. High specific gravity potatoes make the best french fries and dehydrated potato products. Russet potatoes are most often used in processing.

Dehydrated Mashed Potatoes
The chief raw ingredient for dehydrated mashed potatoes are small, damaged, and misshapen potatoes sorted from field run potatoes in major producing areas. The Russet Burbank is commonly used because rigorous grading will eliminate about 50% of the yield from being sold as bakers. About 20% will be process grade. Production is a five-step process.

First the potatoes are precooked and cooled. The peels are removed by various dry brushing methods, the tubers are cooked, mashed and the granules are dried. Sometimes the granules are combined with previously dried granules. Granules are used to make mashed potatoes; extruded products like hash-browns; dry mixes for extruded French fries; and fried, baked and pelleted snacks. Potatoes are also processed into flakes to make mashed potatoes for home use and fried potato snacks. Flakes are used as an ingredient in baked goods, ice cream, pet food, breading mixes and dried soups. They are also used as a binder for fish cakes, fishing bait and eel food (in Japan).

Dehydrated Potatoes
Steam-peeled potatoes are trimmed, diced or sliced, blanched, lightly sulfited, dried, and sorted. Diced products are used for canned food products, potato salad, hash-browns, and dry soup mixes. Slices (usually 3mm thick) are used in retail and institutional casseroles and potato salads. Crushed or ground products are used in extruded snack pellets, as a thickener, in dumpling mixes and potato pancakes, and in dry soup mixes. Elongated strips are used in restaurant hash browns.

Frozen Products
Raw, high-quality, potatoes are steam-peeled, cut lengthwise, sorted, blanched, pre-dryed, and then fried. Customers prefer long French fries so processors use Russet Burbanks from Idaho, Washington, Oregon, Wisconsin, North Dakota, and Maine. Small potatoes and nubbins are used for chopped/molded products, southern-style hashbrowns and fabricated products. New specialty products are being created such as frozen baked potatoes, twice baked potatoes, breaded French fries, waffle chips, curly fries, and mashed potato products.

Potato Chips
A Saratoga, New York chef named George Crum is generally credited with the invention of the potato chip in 1853. They quickly became popular around the country. Potato chips are made by first cleaning and washing the potatoes and then peeling them with a steam peeler. They are then run through a slicing unit which cuts them to the desired slice thickness. The slices are washed to remove slivers and are dried to remove process water. The slices are then are fried in a batch or continuous fryer to produce the finished chip.

Potato Flour
Flour has been made from ground dried potatoes for centuries and was used as a food staple when mixed with water. Now it is used in breadmaking, cookies and candies to improve texture and flavor. Potato flour is also used as a thickener or breading agent.

Potato Starch
First produced in Germany in the late 1700s, potato starch plants were numerous in the U.S. by the late 1800s. These plants have disappeared because disposal of waste effluent from potato starch plants is such a problem. There is only one conventional potato starch plant in the U.S. today. Food grade potato starch is imported from Germany and Holland where the industry is government subsidized. However, starch modification plants exist which convert by-product starch from processing for use in the paper industry. Starch recovery reduces the cost of effluent treatment.

Pre-Peeled Potatoes, Canned Products, and Alcohol

The gas-packed pre-peeled industry has suffered recently concerning the use of sulfite in food products. But this process is still used to produce blanched, panfried French fried strips and precooked shredded potatoes. Canning is still of minor importance. Potato alcohol production is used to make vodka, and also used in the production of gasohol.

Storage Information for Consumers


  • Fresh Michigan potatoes will keep longest when stored in a cool, dry, dark area with good ventilation.

  • Ideally, storage areas should range between 42-48° F. Warmer temperatures encourage sprouting and shriveling. Cooler temperatures can alter the taste and cooking properties of a potato.

  • Never freeze a potato. Fresh potatoes will not cook well and are susceptible to injury when they have been frozen.

  • Avoid placing potatoes in direct light. This prevents greening discoloration to the potato skin which makes them inedible.


  • Scrub your potatoes with warm water. Do not use soap. Without breaking the skin.

  • As an alternative, you may place potatoes flat in dish racks and run them through a soapless dishwasher.


Potato Recipes


Potato Recipes