When it comes to growing cannabis for maximum terpene yields, selecting the proper strain with the terpene profile and effects you’re looking for is an important first step.
“Absolutely number one is genetics,” said Dillon Hryze, lead grower at Denver-based Medicine Man, a vertically integrated cannabis retailer. “After that, it’s sweet, tender care.”
Hryze is very careful with humidity and temperature levels. He said the ideal temperature range for his crop is 75-80 degrees Fahrenheit, with humidity around 40%. That also helps to keep pests and powdery mildew under control.
Keeping your marijuana healthy is crucial to allow the plant to direct its energy toward developing terpenes versus fighting off disease or pests. “If it’s fighting something else, it’s not working on its job,” Hryze said.
He added that applying pesticides could dramatically reduce the production of trichomes, the crystals on the cannabis flower that generate terpenes.
Hryze knows the plant is in the sweet spot for terpenes when the crystals, or trichomes, are around 25%-50% amber in color.
“You’ll have different trichomes changing colors at different times,” he said. “They’re not all going to change at exactly the same time. You’re looking for more of a percentage.”
That can be difficult to time, because each strain has a different life cycle, and each time you plant you can get varied results.
“It’s really playing with the genetics you have,” he said.
If the plants become too ripe, the terpenes will evaporate.
Hryze has noticed an increase in terpene yields from using more organic soil mixtures, meaning more carbon-based nutrient mixes in place of salt-based mixes.
For example, he adds more kelp and seaweed instead of relying too much on liquid salt.
As for lights that yield strong trichome production, Hryze prefers to use high-pressure sodium single-ended lamps. He said they might have slightly reduced yields in terms of plant weight, but the trichome production is better.
In his experience, double-ended lights increase yields, not trichome production.
“A lot of that has to do with how much heat they put out,” Hryze said.
He maintains a distance of 18-22 inches from lights to canopy at Medicine Man. His lights are on adjustable chains that can be shortened or lengthened, depending on the plants.
As far as strains, he prefers to grow Shaw Bud for terpene and trichome production.
“It looks like it’s coated in sugar,” Hryze said, referring to the trichome crystals.