Four Factors To Consider During Potato Storage

Spring has arrived, and for many growers it’s time to get their fields ready for planting. Potato crops are planted early in the season, and most growers receive their shipment of seed potatoes in March and begin planting in April.

Given the uncertainty and unpredictability of spring weather, there may be instances where growers have to delay their potato plantings, which raises the critical question of proper storage conditions. If not stored correctly, there could be a rapid decline of seed potato quality, which can jeopardize the performance and productivity of the future crop. Below are four key factors that growers should consider when storing potatoes:

1. Temperature: The ideal storage temperature for potatoes is 40-45 °F. Warmer temperatures lead to sprouting, and excessive sprouting lowers the quality of potatoes. In addition, warm storage conditions encourage the growth of disease, creating an ideal environment for organisms which could detrimentally affect crop establishment and yield. Warm storage conditions also increase transpiration and respiration which could cause increased water loss. On the other hand, storing at temperatures that are too low can cause potatoes to turn grey or black, and decrease their quality and vigor.
2. Relative Humidity: High humidity is essential to maintain proper seed weight and tuber quality. Weight loss significantly increases at relative humidity below 90%, so be sure to maintain high relative humidity (90-95%) to preserve the quality and firmness of the potato.
3. Light: Tubers will turn green if exposed to light, and the speed at which greening occurs depends on the exposure of the tuber to light. This green coloration is actually chlorophyll, and is generally harmless; however, it is an indication that an increased level of a glycoalkaloid compound called solanine may be present. This compound is potentially toxic if consumed in large amounts. To eliminate solanine formation, seed tubers should be kept away from the light and stored in the dark.
4. Ventilation: Potatoes should be stored in well-ventilated, cool, dark, and humid place. Air movement helps maintain the desired temperature and humidity and suppresses the growth of fungal and bacterial pathogens. It also helps eliminate free moisture (condensation) from forming during storage.

Potato tubers are live and they respond to their environment. Adequate temperature, relative humidity, and air movement are critical components to prevent excessive moisture loss, shrinkage, and decay of seed potato tubers.