Honing Your Trimming Skills

Two cultivation gurus share tips on how to give your plants a first-class trim job

By Omar Sacirbey

Despite the availability of large machine trimmers, many growers prefer to trim their cannabis by hand, using pruners, shears or scissors. Hand trimming – which most growers say results in better quality flower than machine trimming – may seem like straightforward work, snipping leaves wrapped around cannabis flowers. But multiple factors determine a good trim job, including:

  • Drying and regulating the moisture within plants.
  • The particular strains being trimmed.
  • Knowledge of consumer preferences.
  • How managers regulate their trimmers’ workloads.

Hand trimming differs from pruning, when growers cut plants to enhance growth and cannabinoid production. Instead, hand trimming is a craft that requires observation, persistence and nuance for the best results. It is one of the most important procedures in the cannabis production chain.

Trimmers are “the last people to touch the product before it goes to the customer,” said Jesse Peters, CEO and chief grower at Eco Firma Farms in Oregon. “What they do is extremely important.”

Here are tips for how to achieve an expert trim job.

Wet Versus Dry

When Peters started growing cannabis two decades ago, he’d harvest plants, hang them upside down whole and start trimming immediately while the leaves were still wet. The advantage of trimming plants when wet: The leaves are vibrant and stick out and away from the flowers, making them easier to cut versus when the plants have been dried. You also get your product to market more quickly by eliminating the one- to two-week drying period.

Dry trimming, however, has critical advantages. And while dry trimming is more challenging than wet trimming, it’s not as burdensome as one might think and shouldn’t necessarily be discarded.

The big disadvantage to wet trimming is that the THC-packed trichomes and calyxes on flowers and leaves – the most valuable part of the plant – get knocked off in the process, degrading the value of the final product. But with dry trimming, those trichomes are better preserved, said Peters, who now dries his plants before trimming them.

Peters initially thought dry trimming was tough because the first few times he tried it he let the plant dry only overnight. The result was a plant that looked droopy and leaves that would wrap and curl around the flowers that trimmers needed to handle. That made the work hard and left Peters feeling it was not worthwhile.

But his strategy changed about a dozen years ago when peers told him that if he dried his plants thoroughly – for a week or two – the leaves would be much easier to cut.

“If you take the time to let it dry properly, and let it reach a certain moisture level, then it’s not a big pain,” Peters said. His team lets plants dry for about 10 days, although some plants are dry in seven days and others in 14 days, depending on the strain and conditions.

Corey Buffkin, a partner and chief cultivator at Green Man Cannabis, a vertically integrated business in Denver, agreed that dry trimming is the way to go. “We just like the finished product better,” he said.

Moisture Levels

But what is the right moisture level – and what does a grower need to do to achieve it?

Peters reckons he gets rid of about 90% of the moisture in the plant during that one- to two-week drying period.

“You are always monitoring and balancing the temperature and humidity in your drying room accordingly,” Peters said, noting that the plant should have a little bit more moisture in it while trimming versus when it goes to market. “Once that cannabis gets to the right moisture level, you can maintain temperature and humidity levels and keep that cannabis in storage spaces for an exceptionally long time without destroying or damaging the terpene profile.”

Peters believes a good guideline for drying is to keep the humidity at 60%-65% and the room temperature at 60-65 degrees.

But be careful not to dry your plants too quickly or to overdry them because that can damage or destroy the terpene profiles, Peters said. He’s done that and tried to remedy the mistake by adding humidity to the air. The fluctuation of going from wet to dry to wet, however, is bad for the plant.

“If you get that humidity wrong, it changes everything,” Peters said. He learned that by making the mistake of overdrying the plants – and then throwing water on the floor to raise both the humidity level as well as the moisture level in the plants. “You ended with all this good-looking weed but no smell, and its flavor was flat. If you fluctuate like that, you really start destroying the terpenes,” Peters said.

Instruments are available that measure plants’ moisture levels and water activity. But most veteran growers have enough experience that they can eyeball their plants and tell when they are ready. One favorite physical cue, however, is the stem snap.

Peters breaks down his plants into branches that he puts in 20- and 30-gallon bins. He’ll take one of the stems at the thick part and bend or snap it.

“There’s a specific time when there’s enough rigidity to the stem where it doesn’t snap but it doesn’t bend like it’s wet – and its dry enough on the outside that it’s not crumbling and all the trichomes are falling off,” Peters said. “It’s also not as sticky as it was, so you’re not going to destroy it with your scissors.”

Buffkin prefers to dry his plants whole. He aims for about 12% moisture level and said it takes about 10 days to reach that. But he declined to say what temperature and humidity levels he uses to achieve that moisture level.

Field Trim or Not

Another debate among growers is whether to start trimming plants in the field or after harvest.

Peters chooses whether to field trim based on the strain and financial considerations. If growing plants that are destined for extraction or being made into resin, then Peters will field trim – but only the big fan leaves; the smaller leaves are bad for extract quality. If the plant is meant to be sold as flower, then Peters waits to trim off the fan leaves at the drying process.

“If it doesn’t go to extracts, then it doesn’t matter if we get a fan leaf here and there. We’ll do the separation at the trimming table, and it’s just more cost effective,” Peters said. He noted that he starts cutting fan leaves about four or five weeks into the plants’ growing cycle, which usually take eight to 13 weeks.

Some strains have a small number of very large fan leaves that are easy to trim. Others have many fan leaves that are small, making them hard to trim. Those plants with a small number of large fan leaves that are easily removed are what Peters prefers to field trim and send for extraction. Those strains include Hazy Girl, Maui Bubble Gift and Pineapple Kush. Hard-to-trim plants include Sensi Star and Strawberry Cough.

For example, a Maui Bubble Gift plant may have about 20 large fan leaves that are about twice the size of a human hand. Sensi Star plants, by contrast, have about 120 fan leaves that are about half the size of a human palm, making for a more time-consuming trim job. The result: Trimming a pound of Maui Bubble Gift can take about two hours while trimming a pound of Sensi Star can take closer to eight hours.

Eco Firma’s trimmers work over custom tables with built-in screens that capture the kief that falls off plants during trimming – rather than letting it go to waste. The kief can be pressed into pucks, rosin and different forms of extract; it also can be put into many other products.

Buffkin said OGs are “a breeze” to trim while sativas are leafier and can take three times as long to trim. For example, he grows a Skunkberry strain that takes three or four times as long as most other plants, but the time’s worth it because it’s a Cannabis Cup winner strain that sells well.

Tight Trim Versus Loose Trim

Another important question is whether to do a “tight” trim, where all the leaves are removed, or a “loose” trim, where some of the sugar leaves – those that can contain generous amounts of trichomes – are left on.

Which one is preferable again depends on the strain, what kind of trichome content the sugar leaves have, flower structure and the particular demands of the market.

Some flowers are structured more loosely, so they’re easier to damage by destroying trichomes with aggressive, tight trimming. With those types of strains, loose trimming is preferable.

“We tend to trim fairly tight, but some strains you don’t want to trim too tight or you kind of just destroy it,” Peters said.

Another factor is market demand. For example, consumers in Portland, Oregon, where Buffkin has a grow site, prefer tight trims with absolutely no leaves, while those in Denver and Las Vegas, where he also has grows, like to see a little sugar leaf on their flower.

“You have to coach your trimmers every day, tell them tighter or let them know it’s too tight, depending on what you see,” Buffkin said.