Growing potatoes successfully in Oklahoma requires adapting standard cultivation practices to the state’s distinct climate, particularly the intense summer heat and variable precipitation. Potatoes are a cool-season crop, meaning their growth cycle must be timed precisely to avoid high temperatures that halt tuber formation and significantly reduce the harvest. Success depends on selecting the right varieties and meticulously preparing the growing environment before the last spring frost. Focusing on early planting and proper soil management makes a bountiful harvest possible even in this challenging environment.
Selecting the Best Varieties and Planting Schedule
Timing the planting is the most important factor for a successful potato crop in Oklahoma. Potatoes thrive best when air temperatures are between 60 to 70 degrees Fahrenheit, so they must be planted early enough to develop tubers before the late spring and early summer heat arrives. The optimal planting window for central Oklahoma is typically early March, with northern regions following by mid-March. Southern gardeners may plant as early as late February, provided the soil temperature has reached at least 45 to 50 degrees Fahrenheit.
Selecting quick-maturing or heat-tolerant varieties helps ensure the crop finishes before the summer’s peak intensity. Recommended varieties known to perform well include:
- The early-maturing Norland “Red.”
- The high-yielding, main-season Red LaSoda.
- The Russet Norkotah, an early to medium-maturity russet.
- The Superior and Yukon Gold varieties, which offer good resistance to certain common diseases.
Preparing the Soil and Seed Pieces
Potatoes flourish in a loose, well-drained, sandy loam soil, which prevents waterlogging and subsequent seed piece decay. Poorly drained conditions should be avoided, as lack of aeration is detrimental to developing tubers. The ideal soil pH ranges between 5.5 and 6.8, though a slightly more acidic range (5.0 to 5.5) is often preferred to minimize common scab, a fungal disease.
Before planting, amend the soil with well-aged organic material, such as compost or aged manure, to improve fertility and drainage. Use certified seed potatoes, which reduces the risk of introducing viral diseases. Large seed potatoes should be cut into pieces weighing 1.5 to 2 ounces, ensuring each section contains at least one or two “eyes,” which are the growth points.
After cutting, the seed pieces must be allowed to “cure” for one to two days in a well-ventilated, moderately humid environment. This curing process allows the cut surface to form a protective callous layer. This barrier significantly reduces the chance of rot and protects the seed piece from soil-borne pathogens once planted in the cool, moist spring soil.
Planting Depth and Hilling Techniques
The prepared seed pieces should be planted approximately 4 inches deep in the soil. A spacing of 10 to 12 inches between each seed piece is recommended for adequate tuber development and air circulation. Rows should be spaced 30 to 36 inches apart to accommodate the hilling process later in the season. Planting in trenches or furrows is a common method that simplifies both initial planting and subsequent hilling.
Hilling involves mounding soil or organic matter around the base of the growing plant. This technique serves two functions: it protects developing tubers from sunlight and provides more area for additional tubers to form above the original seed piece. Tubers exposed to light turn green and produce solanine, rendering them inedible. The initial hilling should occur when the potato plants are about 6 to 8 inches tall, pulling loose soil up and around the stems.
Repeat this process two or three times as the foliage continues to grow, creating a continuous ridge over the row. By the time tubers begin to form, the soil cover should be approximately 6 inches deep over the original seed piece. Proper hilling ensures the harvested potatoes are safe for consumption by keeping them completely shielded from light.
Ongoing Maintenance and Harvesting
Consistent soil moisture is important for potato plant health, particularly during tuber formation in late spring and early summer. Due to Oklahoma’s high temperatures and variable rainfall, supplemental watering is required to keep the soil uniformly moist but not saturated. Allowing the soil to dry out below 65 percent of its water-holding capacity can stress the plants and reduce the final yield.
Growers should remain vigilant against common pests like the Colorado potato beetle and the fungal disease early blight. Crop rotation is the best management strategy, requiring growers to avoid planting potatoes in the same spot for three to four years to prevent the buildup of soil-borne diseases. Once the foliage begins to naturally yellow and die back (usually 90 to 120 days after planting), the tubers are reaching maturity.
Harvesting should commence about two weeks after the foliage has completely died down, allowing the potato skins to set and thicken. Use a spading fork to gently lift the hills, starting well away from the main stem to avoid bruising or cutting the tubers. After digging, do not wash the potatoes; instead, gently brush off the excess soil and immediately take them out of the sunlight.
For long-term storage, the harvested potatoes must be cured for 10 to 14 days in a dark, humid environment at 45 to 60 degrees Fahrenheit. This process heals minor abrasions and thickens the skin, which extends the storage life. After curing, separate any bruised or damaged tubers for immediate use, and store the rest in a cool, dark location.