Choose an area in your yard to plant the Oklahoma cowpeas. Choose a place with full sun and well-drained, sandy soil. Rake the soil well to remove any rocks or weeds. Work 6 to 8 inches of compost into the soil to a depth of 10 inches.
Dig holes 1 to 1-½ inches deep and space them 2 to 4 inches apart. Space the rows approximately 30 inches apart. Plant the cowpea seeds when the temperature is above 65 degrees Fahrenheit.
Place the cowpea seeds in the holes and cover the holes with soil. Pat the soil down firmly.
Water the cowpeas well for 5 minutes.