Potatoes grow best in areas with nutrient rich soil, ample rainfall or irrigation, along with warm days and cool nights. Nearly 90% of potatoes are planted in the spring after the final frost of the season and harvested in the fall. Potatoes harvested in the winter, spring and summer account for the remaining 10% of production and fill special market needs, such as supplementing the fresh supply or to ensure adequate supply for processing.
Potatoes are planted using seed potatoes, grown specifically for the reproduction of potatoes. Generally seed potatoes are cut so that each planted piece has one to two eyes. In most cases, certified seed is used when planting. Certified seed potatoes undergo inspections throughout the growing season by state certification agencies to guarantee that strict tolerances for diseases are adhered to. Potatoes are susceptible to a number of pests and viruses; and the use of certified seed ensures a disease free seed and provides higher yields.
Seed potatoes are planted approximately 12 inches apart and approximately 4 to 6 inches deep in rows that are between 2½ and 3 feet apart. A hill is formed for each row of potatoes so that the soil forms mounds around the plant, which helps to protect new tubers from the sun. Potatoes are 80% water; therefore, good soil moisture is key in all stages of growth. As the growing season progresses, leaves will develop above ground and roots will develop under ground. The roots absorb the nutrients in the soil, and the leaves absorb sunlight that is converted into energy for tuber-growth and also protect the hill from direct sunlight. As the growing season comes to an end the branches will begin to lose their color and wilt, this is a sign that the tuber skins are setting and they will soon be ready for harvest.
In the U.S., western states account for approximately 65% of production, central states account for 25%, and eastern and southern states account for the remaining 10%. With 90% of all potatoes being harvested in the fall, a majority of the crop is not sold immediately but rather stored and sold throughout the remainder of the year. Potatoes have the physical characteristics that make them ideal for long term storage in specialized sheds. As a result consumers have access to high quality potatoes year-round.
Source: National Potato Council