Longer days and warmer temperatures are signs that planting season is around the corner for hemp growers. When it comes to successful seed planting, some factors are out of growers’ hands—like an unexpected rain. But a few planting tips can help growers give each seed the best chance from the start, laying the foundation for a productive yield.
1. Genetics: Get the Right Seed
The genetics of a hemp seed determine sex, germination rate, flowering time, THC levels, yield, and hardiness. “Identifying good genetics is always the foundation to growing a good crop,” says Ben Brimlow, lead agronomist for IND Hemp in Fort Ben, Mont. “[This includes] identifying the crop that fits [a grower’s] environment, that fits their end-use, and fits the processor quality requirements.” Choosing the right variety will not only reduce the chance of seed mortality, but also encourage a more productive yield.
The right variety for your end-use
Seeds for CBD hemp must be feminized because female plants contain CBD-rich resin. Grain and fiber crops need both male and female plants for harvest.
Hemp is typically photoperiodic. Photoperiodism is the amount of time in darkness that plants will start flowering, also called the flowering response time. Different varieties may be more or less successful in a region due to varying day lengths.
“We’re seeing a trend of hemp flowering earlier as we head south,” says Brimlow. “Here in Montana, which flowers in the end of June, [in the south] we may see it flowering in the month of May, which can impact yield and quality significantly. Because once that plant switches from vegetative growth—or vertical growth to reproductive growth—it stalls. … Varieties go from emergence straight into flowering. They didn’t get above two feet tall, and then the weeds [came] up behind it.”
Resources like the Midwestern Hemp Database record cultivar success in certain areas. This information can help you choose a variety that has proven to flourish in your region.
Find a reputable variety
Brimlow recommends verifying your seeds, especially those grown for CBD. “Oftentimes, you’ll have folks who come to you peddling different varieties that might not be exactly what they say it is,” says Brimlow. “Especially in the cannabinoid market there are off-strains and off-shoots of germplasm that might be good, but oftentimes they are not. So [start] with a reputable variety and then [find] a distributor.”
Brimlow recommends using university extensions to find a reliable variety because they are research-backed and verified through testing, like those in the Midwestern Hemp Database.
2. Understand Your Soil
It’s a common belief that hemp can grow anywhere, but just because it can does not mean that it will thrive, says Brimlow. Whether you are planting indoors, outdoors or in a greenhouse, ensuring your soil is well-draining, exhibits low weed pressure, and has plenty of nutrients will lay a healthy foundation for your seeds.
Test Your Soil
To understand your soil condition, Brimlow recommends getting your soil tested. For outdoor production, growers can work with a crop consultant. You can find a crop consultant at your local agriculture center or farmers co-op where you buy fertilizer.
The crop consultant will undertake the scientific process of extracting and interpreting representative samples. These tests will identify high and low zones and provide growers with a good understanding of soil condition and nutrient needs. Brimlow suggests growers should note any products applied to the soil in the last two years, which may affect composition. The best time to test your soil is a few weeks before planting, to get fertilizer plans together in time.
Once you understand soil conditions, you may need to fill in nutrient gaps with fertilizer. For example, acidic soil may need lime to balance pH, and grain hemp requires a lot of nitrogen.
Brimlow reminds growers that fertilizer is best applied off to the side of the seed row— not directly in the seed row— which could burn the plants. Broadcast fertilizing might allow weeds to beat out hemp seeds for essential nutrients, so choose a method that works best for your crop.
3. Timing is Everything
There are several environmental factors that contribute to successful planting outdoors. “In the field you don’t have the ability to manipulate lighting like you do in a greenhouse or indoor environment,” says Travis Higginbotham, a former owner of The Hemp Mine in South Carolina. “So you have to strategically plan your production outdoors so that you maximize the environment at the location where you are.”
A successful crop all comes down to good timing: a small chance for frost, coordinating day length to your variety’s flowering response time, and planting before a rain. This is why Higginbotham helped create the Hemp Mine Map, a virtual resource that helps growers understand frost potential, date at different frost potentials, and day length for different regions across the U.S.
Growers can find a date with low frost potential and a day length that is above their chosen variety’s flowering response time. This is the ideal date for planting.
Hemp seeds are not fond of “wet feet” so Brimlow also recommends planting after a rain and not before. Overwatering can delay germination or increase seed mortality.
4. Crop Density
Hemp seeds prefer a shallow (1/2” is ideal) and firm seedbed, according to IND Hemp. The density of your seeds depends on your end-use.
Grain hemp is planted at 25-35 lbs. per acre. This encourages a thicker stalk which can handle the weight of the grain head on top.
Fiber crop prefers 40-60 lbs. per acre, forcing the plants to have thinner stalks and more vertical growth.
The goal for CBD hemp is to have plenty of space for bushy crops. Growers should plant seeds at 1,000-2,000 plants per acre (<1 lb./acre), if planting outdoors.
Successful hemp production needs preparation and excellent timing when it comes to planting. This spring, take advantage of these four tips to make sure your crop is off to a great start.