The nitrate-N value provided by the OSU soil test report should be used to determine N fertilizer needs on a particular soil. Soil Preparation and Planting Rework the soil just before planting to destroy any weeds and to develop a clod-free seed bed needed for mechanical harvesting. Make the earliest plantings in late April in central Oklahoma but make sure the soil temperature has been 70 F or above for several days prior to planting. Do not plant later than July 15. Plant in rows 18 to 42 inches apart depending upon variety and equipment to be used in planting, cultivation, and harvest.
Bunch varieties require wider spacing.
Three to four seeds should be planted per foot of row. Size of seed determines the amount of seed to plant per acre. Seeding rates vary from 15 pounds per acre for small seeded varieties to 30 pounds per acre for larger seeded types when planted in 36 inch rows. The use of herbicides is becoming more important with mechanical harvesting and as plant populations rise. Cultivate just deep enough to control weeds.