By Justin Pullin
Making a first dive into harvesting, drying, and processing industrial hemp for CBD is something you never forget. A very different crop from what most farmers are used to, the hemp plant’s challenges are unique — if not downright alien.
Crops like fruit, vegetables, and hay come with similar rough challenges and labor, but hemp’s an entirely different beast.
It’s sticky with resin and can be a real bear to handle. It can be unpredictable, particularly near harvest when it requires a sharp eye to maximize those valuable cannabidiol (CBD) levels.
You’ll also be walking the tightrope of minimizing THC content.
To preserve the highest possible CBD, you’ll want to handle the plants carefully or risk bursting trichomes on the plant’s surface that create cannabinoids.
As is the case with lots of crops, hemp is often at the mercy of Mother Nature’s whims. But hemp is also extra-sensitive to bugs, weeds, and molds due to shifting government rules around using insecticides, herbicides, and fungicides.
Let’s take a closer look at some of the best tips you’ll need to know in order to harvest and process hemp for CBD.
Testing THC Levels to Protect Hemp for CBD
One of the challenges you’ll face is knowing exactly the best time to cut your hemp plants.
The goal is to maximize CBD content while minimizing THC levels.
It’s helpful to run preliminary tests of cannabinoids using third-party labs — prior to your state-mandated tests — to see where you’re at with CBD and THC levels.
It’s key to make sure plants remain below the legal federal threshold of 0.3 percent THC. That number is your absolute outside percentage of THC allowed. Testing on a weekly basis beginning in the early bloom phase will be critical.
As THC levels approach 0.2 percent, you’ll need to start seriously thinking about harvesting your hemp. From there, THC can suddenly jack up over 0.3 percent and put your whole crop in jeopardy.
Too many hemp farmers got caught with “hot plants” that had to be destroyed in 2019, testing over the 0.3 percent threshold.
There are visual cues, too, that you can use to see that plants are approaching the harvest window — but they’re hard to catch with the naked eye. They’re best viewed using a relatively cheap 40x-60x zoom pocket microscope.
That handy device will show you the tiny glands called trichomes on flower surfaces. Similar to the changing of fall leaves, they’ll turn from clear to milky white to amber when the flower is nearing completion.
Protecting Your Hemp Harvest From Weather Conditions
It’s a fairly basic concept to tell a farmer to keep an eye on the weather. But with hemp, it’s critical.
Rain and wind can mean substantial water collection on beefy flowers that are hitting their peak in September and October. The last thing you want is to break a branch and burn profits.
Mold and disease are big worries during flowering time, so pay attention to airflow around your plants. In some cases, that means spacing plants in a way that allows for adequate air.
Humid climates could require more spacing and air for your plants, while in dryer climates it’s less of a consideration.
Keep in mind that greater spacing doesn’t have to mean less yield.
More space between plants can also mean more room for bigger plants.
The Right Tools Can Safeguard Your Hemp’s CBD Content
There are some must-have tools you’ll want when processing hemp plants by hand, including gloves, heavy-duty shears or tree/shrub loppers, and machetes.
For mechanical harvesting, some farmers found it more efficient to chop plants using a sickle mower connected by gooseneck behind a tractor. That made quick work of cutting.
Plastic carrying totes are great to have in the 20- to 30-gallon range. Totes are ideal for transporting processed plants and are the best carriers to avoid overpacking and bruising flowers.
A key thing to remember is to handle your plants with care. Think of it like fruit. The more you move it, the more bruising potential.
Every stage of cutting, hauling, and drying disturbs those precious trichomes that carry CBD.
You’re looking to maintain the integrity of the plant through every stage of processing hemp for CBD. For instance, some hemp farmers find it necessary to cover trailers in visqueen to keep plants off hot surfaces (like metal) and preserve trichomes and terpenes.
Every time you move or handle the plant during this process, you risk CBD levels dropping.
So keep movements to a minimum.
Some farmers prefer to cut plants whole at the base of the stalk and carry away the entire plant. Others begin at the top of the plant, harvesting the largest top flowers first and working downward.
Whole-plant harvesting is faster for transport to a drying space, but this approach will lead to slower drying times due to greater plant volume. That stalk contains a lot of water weight.
Cutting away branch by branch requires more time investment but leads to a faster hang dry.
Chopping mechanically is far quicker — but again, it’s harder on the plants and you want to preserve those trichomes.
Hang Drying Hemp for Mold and Dust Prevention
For hang drying, it’s helpful to dissect the stalk and branches to form check-mark shapes that create a natural hanging infrastructure. That hooked shape will make for a perfect area to line dry the branch and buds.
Setting up a hang-drying zone is preferably done in a large room, barn, or overhanging structure where plants can be hung upside down from wires set up like clotheslines.
You should make sure that drying facilities are clean and free of dust and other matter that could taint sticky, trichome-heavy flowers. Leave enough room between hanging plants so they get plenty of air movement — a good exchange of air around plants is vital.
Low-velocity air that creates a gentle breeze all around — and doesn’t blow directly on the plants, which can dry them too fast — is best. If possible, keep your hemp plants out of direct sunlight to protect the CBD content.
Generally, an acceptable temperature range for hang drying hemp is between 60 and 75 degrees Fahrenheit, with humidity between 40 and 70 percent.
In humid conditions, pay particular attention to airflow.
The aim is to continuously wick away bound moisture content and get your hemp below 10 percent moisture. The lumber industry has some great moisture meters that check for water content. They’re inexpensive and a great tool to have to avoid drying too fast.
Hang drying typically takes between seven and 10 days, depending on conditions of the facility and climate. Keep a close eye on plants for mold during this time. As they slowly dry, they’re open to attracting mold.
When to Consider Mechanical Drying a Hemp Harvest
You’ll want to consider mechanical drying if you’re farming more than a few acres of hemp. Wet plant weight can add up fast and be a real chore to dry by hand.
Also, if you have limited space for drying, you’ll have little choice but to go the mechanical dry route. Time and space are going to be major factors in deciding your drying process.
There are a thousand ways to skin a cat. You should go with what feels right for your particular space.
When drying hemp mechanically, the bucking process means that growers spend far less time cutting branches and setting up drying areas. Buds are rapidly whipped off of branches, similar to shucking corn, and placed into totes for transport to drying.
Remember, all this commotion that comes with bucking plants will mean a decrease in CBD amounts. However, the payoff is the time you’ll save.
The mechanical drying process is far more efficient and can be completed in as little as one to two days, as opposed to hang drying which can take seven to 10 days.
There are a growing number of advancements currently happening in mechanical hemp drying, so options for this type of drying are expanding constantly.
Also, this year there are bound to be even more co-ops than there were in 2019 that have drying systems available for members, and even more machine rental companies that will be jumping into hemp drying.
Mechanical methods have the upside of saving hemp farmers a lot of time and effort, but a loss of CBD is your trade off compared to hang drying.
You’ll have to decide which is your best fit.
Remember, there’s not a particular way to dry hemp — mostly it’ll come down to your own personal needs, space, and time commitment.
Dial in your best drying process and you’ll get the most CBD out of your hemp that’s possible.
