All season long you've put in hard work to grow your cannabis plants from little seeds or seedlings. Finally, the time has come to harvest. But just like a kid going off to college, it's a precarious time — your adult plant may look big and strong, but its trichomes are at their most vulnerable come harvest.
Without proper drying and curing, your harvested weed can also develop mold and fungus. Knowing how to properly harvest, dry, trim, cure, and store your cannabis will go a long way in ensuring all your hard work pays off.
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How to tell when buds are mature and ready to harvest
Before cutting down your plants, you need to determine when they are ripe and ready for harvest. Harvesting too early will reduce the overall yield and potency of your weed, as the last two weeks of harvest is the peak time for cannabinoid production. Yet harvesting too late can cause the trichomes to become extra-brittle when they are dried and cured, making them break off easily.
While this may sound stressful, the harvest time isn't an exact day but more of a window. Most healthy plants stay in this window for 2 – 3 weeks or even longer for the strains that take a very long time to flower.
How to harvest cannabis
When the grow medium is flushed and buds are in the harvest window, it's time to cut down some weed. The overall goal is to create colas that will be easy to handle for the next stage and preserve the buds and their precious trichomes by disturbing them as little as possible throughout the harvesting process.
What you'll need:
- A pair of appropriately sized clippers. For indoor plants, a pair of scissors is usually enough unless working in a large grow space. For outdoor and large indoor grows, a pair of garden clippers or even a set of loppers may be needed.
- Two harvest bins: one for the initial clippings that will be discarded and — most importantly — a clean harvest bin to hold your freshly harvested buds.
- Twine or something to tie up and hang your cut branches.
- Medical gloves to keep your buds free from contamination.
- Isopropyl alcohol to help disinfect your tools and keep gloves and trimming tools clean when resin builds up and things get sticky.
A step-by-step guide to harvesting cannabis:
Time needed: 21 days
- Time the harvest for success
Timing can make or break a harvest. If it's supposed to rain on harvest day for an outdoor grow, wait for the next dry day if the situation allows. Ensure there is plenty of time to complete the tasks of harvesting and trimming.
Once you've begun, it's important to get buds all the way into the drying stage and not leave them languishing in a harvest container for more than a few hours. So give your weed the attention it deserves and pick a morning when you have nothing else to do all day to harvest. - Clean your supplies
Make sure all of your supplies are clean and disinfected with isopropyl alcohol.
- Set up your drying space
Prepare a room with the temperature set at 70°F (21°C) and a dehumidifier set at 50% — a closet should work nicely.
- Remove fan leaves from the branches
Identify a branch to start with and remove all remaining fan leaves, leaving any sugar leaves and bud sites alone. With today's strains bred for maximum potency, sometimes fan leaves develop trichomes as well, though these trichomes tend to mature last and therefore are not always developed enough for the trim bin for further processing.
- Cut down whole branches
Remove the whole branch in roughly arm's length sections. Shorter-length sections are easier to handle for trimming weed while longer branches tend to be heavy, increasing wrist strain and the chance that the buds will be damaged through mishandling. If cola tops are particularly dense and heavy, consider removing them in even shorter sections.
- Decide whether you want to wet trim or dry trim
At this stage, some cultivators will opt to trim, yet others will choose to dry their weed first and trim after. Trimming immediately after harvest is the easier method for beginners, as sugar leaves haven't dried up and closed in on the buds.
The method of choice will also depend largely on location and time of year, in humid conditions, a wet trim is preferable as the moisture left in the leaves can lend to bud rot and other fungal issues while drying. In drier environments, that same leaf moisture slows down the drying process, ensuring buds don't lose too much water in a short period of time.
If you're wet trimming, move to a comfortable space. Work in a clean, open space that is comfortable to be at for long periods of time, such as a table, desk, or countertop. Ideally, the temperature should be controlled between 65 - 70°F with little to no moving air directed at the workspace from fans or HVAC ducts. - Cut away sugar leaves and stems
To hand trim cannabis buds, hold them by a stem close to the bud group being worked on, and gently cut away the sugar leaves and their stems. For leaves that you can see the underside of, target the crow's feet — the point where the individual leaves join together — as closely as possible without doing damage.
For leaves sticking out between buds, trim as close to the bud as you can while being as gentle to the flower as possible. A small dab tool or toothpick can be used to gently pry tight buds apart. - Handle the fresh buds carefully
All contact with the bud can cause trichome loss or damage so handle it with extreme care. Hold your plants and branches by the stem whenever possible and work from one end of the branch to the other to avoid repeatedly handling the same buds.
- Hang your freshly cut branches
If you're dry trimming, take the branches to your drying room and hang them up so they have plenty of space. Avoid letting your branches hit any surfaces while hang-drying. Contact with a surface can damage trichomes and break them off of the plant. Depending on environmental conditions, the initial drying process usually takes 3 - 7 days.
- Cut your partially dried branches into smaller sections
Once the stems are dry enough to snap slightly when bent, remove them from the lines and cut them into smaller sections. Place those sections inside a large tote and close it with a lid. Do not seal or close the lid completely.
For the first couple of days, turn over and rotate the cannabis in the totes to ensure even drying. Also “burp” the totes in the first couple of days by opening them and allowing fresh air to filter out the damp air inside. - Cure your weed
Curing is the final stage in the drying process, allowing for a controlled breakdown of residual chlorophyll in the colas so that they are neither too moist nor too dry.
To cure your buds, place them in glass jars or a tote for about 4 - 8 weeks. During the first two weeks, open the containers daily and allow fresh oxygen to filter through the air in the container. Open the containers every 2 - 3 days in the last two weeks of curing. The curing process should be gradual to ensure a proper balance of air and moisture that will preserve fragrance and flavor.
How to store weed properly
In order to maintain the chemical profile of cannabis, the buds must be kept as close to their final condition as possible. Improper storage can lead to cannabinoid degradation, loss of terpenes, harsh smoke, loss of trichomes when flower is brittle, and development of mold or fungus if cured flowers are overexposed to moisture.
Keep these factors in mind when storing your weed:
- Temperature: Cannabis should be kept in a cool, dark place, preferably at room temperature or slightly below. High temperatures can lead to mold and mildew, can dry out your flower, and turn sensitive terpenes into vapor, which will ultimately change the effects of the flower. This is why some cultivators skip drying and make live resin extracts to preserve all the monoterpenes lost during the drying process. If the temperature is too low, THCA would be harder to decarboxylate into THC, thereby reducing the potency of the flowers when they are smoked. It can also make the trichomes brittle on the plant, which could cause them to break off when removed from the cold environment. This isn't necessarily a huge issue, though, as those trichomes can be collected as kief and smoked. To limit your bud's exposure to high or low temperatures, keep it inside, away from windows, and in a cool, dark place. If you're traveling outside with your bud, consider storing it in a vacuum-insulated bottle.
- Moisture and water activity: Moisture is the amount of weight, as a percentage of the total weight, that is lost if the material is completely dried out. Water activity is the amount of water on the surface of the plant. Both are important factors in preserving the integrity of your bud. According to ASTM Internationals cannabis subcommittee, the amount of water activity on cannabis flowers should be in the range of 0.55 to 0.65.
- Oxygen: The most precious cannabinoids in your bud will degrade if overexposed to heat or oxygen. THCA, for example, will decarboxylate into THC prematurely when exposed to heat, and therefore reduce bud potency. When exposed to oxygen, THC will degrade into CBN, a compound estimated to be one-fourth the potency of THC. Oxygen can also oxidize essential terpenes, leaving behind a grassy, sometimes haylike aroma. To reduce exposure to oxygen, avoid air pockets in your container whenever possible. For example, don't use a container that holds an ounce (28.35 grams) to hold a gram of flower. Vacuum-seal your flower for long-term storage, and consider getting a hand-held vacuum pump for short-term storage. Glass jars, ideally opaque and airtight for ample cannabinoid and terpene preservation, will also make adequate short-term storage.
- UV Light: UV light is the biggest factor in the degradation of cannabinoids, and ultimately the shelf life of cannabis. UV light will always degrade your cannabis, so that's why cultivators are now using opaque packaging instead of clear glass. UV light is another sizable contributor to THCA degradation into THC and CBN, significantly decreasing potency before it reaches the end consumer. UV light will also degrade CBD. To avoid cannabis degradation from UV light altogether, use opaque packaging or brown glass bottles to store your weed. Brown bottles allow 30% of UV light to pass through, as opposed to green and clear bottles, which allow 70% and 100% of light to pass through.
Bottom line
Properly harvesting, drying, and curing cannabis is a dedicated practice that takes trial and error for home growers and professional cultivators alike. But the extra care is worth the time it takes to master these steps and preserve the integrity of your flower.