Planting the Seed
The ideal planting season for industrial hemp in South Dakota is early May, when soil temperature reaches 50°F. When planting hemp seed, it’s best not to chase moisture too deep, or you risk crusting over. A half inch to 1 inch is sufficient, but you will want good seed-to-soil contact. Consider rolling your field after planting to ensure an even emergence of your crop. We recommend using a grain drill because your rows will need to be fairly close for making its canopy. Between 6- to 15-inch-wide rows are ideal for weed control. Either an air drill or a mechanical drill will work on the sorghum-sized setting. The only chemical approved for hemp in South Dakota is a pre-emergent called Sonalan. It helps to keep the weeds down while your crop establishes a canopy.
There are two ways to grow industrial hemp: one is for the grain (Seeds) and the other is for fiber (Stalks). Learn more about our hemp products.
Growing for Grain
When growing for hemp grain, we have found that 30 lbs of hemp seed per acre is ideal for uniform field height. During your growing season, the recommended fertilizer rates are 120/30/20 NPK for grain types of hemp. You will know it’s the right time to collect the hemp seed if you can clap your hand a few times with a seed head, removing around 40% of the total seed. Another indication is the number of mourning doves inhabiting the field and power lines. Use a regular bean head combine to target the upper 2–3 feet of the seed head, leaving residual stalks. Recently, we switched our head from an auger to a drape for a steadier flow entering the feeder house. We also found that swapping concaves to larger openings allows the seed heads to enter without wrapping. The hemp seed is harvested at 20–25% moisture, so get the grain on air immediately. Avoid heat when drying the seed to preserve hemp seed oil. Keep your crop in your bin on air until it reaches 10% moisture.
For more details on our hemp seed products, visit our shop page.
Growing for Fiber
When growing for hemp fiber, we have found that 22 lbs of hemp seed per acre is ideal for uniform field height. This is a 100-day crop planted in early May and harvested in September. During the vegetative stage, the hemp stalks grow tall and fast, making weekly jumps in height. Once sunlight reaches a certain number of hours per day, your plants shift to reproductive mode, and your field may only gain another 1–2 feet. Harvest before the hemp seed reaches full maturity. Monitor your field by evaluating fiber development: cut a stalk into 18-inch sections, checking the air space in the center. As the plant matures, the center fills with hemp hurd, resulting in greater tonnage. Harvest with a sickle bar or swather (with crimpers spread), leaving 6 inches of stalk to protect your tires and create an air bed. The stalks remain in the field for 2 weeks for retting, naturally removing lignin in the outer hemp fiber. After retting, use a rake to form rows, leave them for 2 more weeks, and then use a round or square baler.
Check our hemp fiber products for bulk orders.