Potatoes require precise timing for successful growth in Arkansas, needing a cool period to form tubers before the summer heat arrives. As a cool-season vegetable, potatoes thrive when conditions are neither too hot nor too cold. Understanding the distinct seasonal windows for planting is the first step toward a successful harvest.
Optimal Timing for Arkansas Potato Crops
The Arkansas growing season allows for two main planting periods: a primary spring crop and a smaller fall crop. Spring planting must be timed so tubers develop during the cool months of April and May, before soil temperatures consistently exceed 80 degrees Fahrenheit. The definitive signal to plant is a soil temperature of at least 50 degrees Fahrenheit. Planting too late causes tuber development to cease prematurely when high summer temperatures arrive.
In southern Arkansas, planting occurs from mid-February through early March. Northern and mountainous regions, which have later frost dates, typically plant from early March through early April.
For a fall harvest, midseason or late-maturing varieties should be planted between July 15 and August 1. This timing allows the potatoes to mature during the cooling weather of early fall. Fall-planted potatoes require 100 to 120 days to mature fully and are often the best choice for winter storage.
Preparing the Seed and Soil
Preparing Seed Potatoes
The process begins with selecting certified seed potatoes, which are free from common soil-borne diseases. Larger seed potatoes must be cut into 1.5- to 2-ounce pieces, ensuring each segment contains at least two or three healthy “eyes.” These cut pieces should be spread out in a cool, well-ventilated area for one to two days. This allows them to develop a protective, cork-like layer, which prevents rotting after planting.
Soil Requirements
Potatoes perform best in a loose, well-drained, sandy loam that allows for easy tuber expansion. Heavy clay soils must be amended with organic matter to prevent compaction and ensure adequate drainage. Waterlogged conditions can cause physiological damage to the developing tubers. Maintaining a slightly acidic soil pH, ideally between 4.8 and 5.6, helps suppress the development of potato scab.
Seasonal Care and Harvest Indicators
Hilling and Watering
Once the plants emerge, the most important cultural practice is hilling, which involves drawing loose soil up and around the stems. This should be done when the plants reach six to eight inches in height, covering all but the top few leaves. Hilling encourages the formation of more tubers along the buried stem. It also prevents sunlight from reaching the developing potatoes, which would cause them to turn green and become inedible.
Consistent water is necessary, especially during hot summer months, to keep the soil temperature within the optimal range of 60 to 70 degrees Fahrenheit for tuber growth. A uniform water supply is important for quality, as inconsistent moisture can lead to misshapen or knobby tubers.
Harvesting
For an early harvest of “new” potatoes, gently dig beneath the plant after it begins to flower, typically seven to eight weeks after planting. These thin-skinned potatoes do not store well.
For full-sized storage potatoes, wait until the plant foliage has completely yellowed and died back, a process called senescence. This die-back indicates that the tubers are fully mature. Waiting a few days afterward allows the skins to “set” or toughen for better storage. Fall crops should be harvested after the vines die down but before the first heavy freeze.