Cannabis Growing 101: Drying And Curing
Posted by Matt Leonetti (he/him) on 16th Sep 2021
There's no time like harvest time for the cannabis grower. It's the culmination of months worth of work, time, energy and undoubtedly some challenges along the way. It’s also one of the most important aspects of growing: to capture and preserve the essence of the plant at peak ripeness.
But how do we know when that time is and how do we preserve it? I've said it a million times and I'll say it again, cannabis is one of the most personal experiences out there and everyone has their own approach to how it’s done. So a lot of this will be your personal choice.
However you grow, getting to harvest is always a great achievement and feels like success. And to some extent it is, but this is also where the real work begins. In fact, the period from harvest through final curing may be more important than the growing itself. Your post-harvest activities can either improve the taste and smell of your flower, or result in the exact opposite, with your crop tasting harsh and with little flavor.
In the early days of cannabis cultivation, peak ripeness was associated with the change in color of the pistils - the little white hairs protruding from the bracts, standing waiting for pollen. The hairs would most commonly change to an orange or reddish hue, although the range of colors could be about anything.
Today, growers tend to determine peak ripeness by the color of the trichomes - the tiny glandular protrusions (resin glands) covering the bracts and sugar leaves.
Peak ripeness occurs when the trichomes swell and change from clear to a milky hue. This is seen by using a jewelers loupe, a simple magnification glass. You want to keep too many trichomes from turning amber in color, since that’s a sign of degradation. You’ll never get all milky trichomes, since the plant ripens differently in different areas at different times, but cultivators generally clean off their scissors the moment when there are mostly milky trichomes with some ambers.
So you’ve checked the trichome color, the hairs are withering, and the plant has thrown a beautiful fade at you (he fade is the pull back of chlorophyll from the leaves where we get beautiful mixed colors of yellows, reds, purples).
But when do you actually harvest?
There are many approaches to the exact timing of the chop, but we prefer to take our plants right before the sun rises or the lights go on.
Terpenes, the plant's aromatic oils, are at their peak during the dark hours as part of the plant's defense mechanism and we want to capture that peak as well.
When we chop, we take the whole plant down, trimming the plant into smaller, uniform sections so that there will be a more even, consistent dry.
The Drying Room
The drying room is very important and will determine to some extent how well you’ve preserved all your months of prior hard work. Not everyone can have a medical grade facility with HVAC systems and atmospheric controllers. But, what everyone should have is a dark room, clean and free of dust, dirt, pets and constant travel.
Stable temperature and humidity are key to a smooth, uniform dry. Optimal temperatures for the first few days are right around 68F - with humidity around 55% - to get the water content down to 30-40%.
Temperatures should be dropped a bit from there (64F) to slow the process, further allowing the chlorophyll to decompose and the starches to be used up.
If plants dry too quickly, more chlorophyll remains and the taste tends to be bitter and green. This process usually takes around 10-14 days but varies considerably based on your setup.
The drying stage is complete when you bend the stem of the plant and get a firm snap. Now comes the trim before we go into whatever means will be used for curing. This is another step everyone does a little differently. In fact, some folks trim before hanging the plants up to dry.
Whenever you trim, the more chlorophyll-filled leaves you remove, the finer the smoke. Handle the buds lightly, use gloves and trim in a clean area over a trim tray or something to collect all that precious and valuable trim.
Generally folks prefer to cure their buds in glass jars, since some plastics can off-gas their components into the final product. But glass jars aren’t feasible for everyone, especially for larger scale growers, and for that we suggest using food grade 5 gallon buckets with sealable tops.
The curing process is possibly the most overlooked aspect of growing cannabis. During curing, moisture continues to draw from the center of the bud toward the outside, and thats what we’re ultimately trying to remove.
Curing affects the flavor and quality of the smoke. Many terpenes, which give cannabis its unique smell and flavor, are very sensitive and can degrade and evaporate at temperatures as low as 50°F. A slow cure at low temperatures will preserve terpenes better than a quick, hot dry, and that’s what we’re ultimately after.
A proper cure also allows you to store cannabis for longer periods without worrying about mold or cannabinoid or terpene degradation. Well-cured flower can be stored in an airtight container in a cool, dark place for up to two years without significant loss of potency, so treat your buds well for best long term storage, taste and potency.
Your finished trimmed cannabis should be stored in airtight containers, preferably glass, but you can use metal or ceramic containers as well. Do not overpack your cannabis, loosely fill your containers, leaving some excess room, seal and set them in a cool dark place.
The packed cannabis within a short period of time, day or so, will begin to feel moist again. This is normal and it's merely the trapped moisture inside the stem and bud that is being pulled to the drier portions of the flowers. This is what we want and expect to see.
During the first week of curing, regardless of humidity level, open the containers once or twice a day for a couple minutes—this is called burping. This releases moisture and replenishes oxygen inside the container. After the first week, burp containers only once every few days.
Our Secret Weapon
One product we’ve had the luxury of trying and using is the Cannatrol, a one stop shop for both drying and curing.
I won’t lie. I was hesitant at first, as well as a bit skeptical. But the unit arrived and we filled it with some of our terpy flower. It’s a smaller unit, the size of a small wine cooler, and it came loaded with trays for gently holding the flowers. We set the program for our desired settings and durations and shut the door.
As part of our intro into this we also dried some of the same flower our traditional way as a point of later comparison. The Cannatrol folks took our labeled samples and sent them in for testing.
As luck would have it, the test results didn’t lie. They also didn’t make me feel so great about our own methods since the results from the Cannatrol-cured flower were several points higher for both THC content and terpene expression. We were sold, and this unit is in constant use with our own perfect, personalized settings.
Cannabis is and always will be a very personal experience. Hopefully, some of these foundational basics will guide you as you experiment and look for the best way to enjoy all your months of hard work.