Oklahoma is a state known for its fertile rolling plains. Here’s a look at whether the state has the necessary condition for growing high quality hemp.
Plant Hardiness Zone(s)
According to the USDA Oklahoma plant hardiness map, the state is divided in to a variety of zones ranging from 6a to 8a, thanks to its varied geography. The state has mountainous regions in the east-central and southeastern parts, rolling hills, river valeys and plains in the northeastern counties and the western edge which is part of the Black Mesa complex. Industrial hemp is classified as a zone 8-11 hardy plant.
Due to the varied geography of the state, Oklahoma has a humid subtropical climate (mostly in the eastern part) and semi arid climate (covering most of the western regions). The Gulf of Mexico blows warm moist air which hits the eastern and southern parts of the state first, resulting in warmer and wetter weather as compared to northern and western parts, which are farther away. Average annual temperatures are 56 degrees Fahrenheit in the west, 56 degrees Fahrenheit in the north and 62 degrees Fahrenheit along the Red River and surrounding areas.
Length of Growing Season
Oklahoma has a relatively long growing season, thanks to the mild weather. The average length of the growing season varies from 170 to around 230 days per year, starting from around mid-February to October or November, depending on the specific part of the state. It is longest in the southern parts of the state, and shortest in the north-western parts. From planting and maturity, hemp requires an average growing period of 120 days.
Average Annual Sunlight
For hemp plants to develop long and strong fully grown stems they need more than 12 hours of sunlight each day during the vegetative stage; otherwise, they transition into the flowering stage prematurely. Most of Idaho receives an average of around 2900 sunlight hours each year. This translates into just over 8 sunlight hours each day of the year. Between the months of April and September, most parts of the state receive more than 12 hours of sunshine.
Average Annual Precipitation
The general rule of thumb in the state is that average annual precipitation decreases as you move to the west from the east. Average annual precipitation in the southeast is as high as 56 inches, decreasing to 17 inches in the northwestern edge of the state. For the best growth, hemp requires a minimum of 25-30 inches of rainfall per year.
The state stands at a mean elevation of 1,300 feet above sea level. It rises from the Little River, at 289 feet above sea level, to 4,973 feet, at the Black Mesa. Hemps seeds should only be planted at attitudes no higher than 600-800 feet.
Oklahoma’s soil pH levels vary from acidic in the southeastern region to neutral in the central region and alkaline in some western regions. These variations are mainly due to the geographical differences of these areas, as well as the farming practices adopted in the eastern plains. Hemp grows best in soils that have a pH level of 6 to 7.5.
Port silt loam is the official soil of Oklahoma. These soils cover most parts of central and western Oklahoma. This soil is well-drained, moderately aerated, and highly productive when it comes to farming.
One of the biggest threats to hemp cultivation in the state of Oklahoma is the European corn borer pest.
Obtaining A Hemp Grower’s License In Oklahoma
Under federal law, it is illegal to grow hemp anywhere in the United States without first obtaining a grower’s license from the appropriate regulatory body for the state in which the interested party intends to plant the crop. For information on the legal status of hemp in Oklahoma, as well as a breakdown of the application process, click here. Read about hemp legality by state.