How to Properly Harvest a Cannabis Crop

It takes roughly three months to grow a marijuana clone to full maturity. When starting from seed, it can take even longer. After putting in that much time and labor throughout the growing process, the last thing a gardener wants to do is botch the harvest. After all, when and how a gardener harvests the marijuana crop will have a dramatic impact on the finished product’s flavor and overall quality. If a gardener is growing cannabis for more than personal use, the flavor and quality of the finished product will affect its marketability and profitability.

Although not technically part of the growing process, it is usually up to the cannabis horticulturist to implement a harvesting technique. Just like the growing process, the harvesting process should be approached in a series of stages. And, also similar to the growing process, there is more than one way to obtain good results. However, certain guidelines should be followed to ensure the grower reaches the full potential of his or her garden.

Patience

Patience, patience, patience. It cannot be stressed enough. It is very easy to get overly excited as the marijuana plants reach the final stages of flowering. Many novice growers make the mistake of harvesting before the plants are actually ready. Many years ago, when I began cannabis gardening, I was guilty of making this common mistake. All I can advise is: be patient. In many cases a gardener’s patience will be rewarded in both an increase in yield and in quality.

The average length of cannabis’s flowering stage is around eight weeks. As the plants approach the 7th week of flowering, a grower can start to monitor the visual signs of maturity. The best tool for this job is a magnifying glass or pocket microscope. Many growers choose a magnifying tool with the magnification power of between 10x and 30x. With one of these devices a gardener can closely examine the trichomes and make a decision on when to harvest based on their concentration.

The trichomes are the essential oil glands that harbor the vast majority of the plant’s cannabinoids, including THC and CBD. As trichomes mature, they turn from a translucent color to a cloudy white color, and then, finally, to a dark amber color. The key is to harvest when the vast majority of the trichomes have become white and cloudy. This usually means there are also a fair amount of amber and clear trichomes. The idea is to maximize the amount of “ripe” trichomes. If a grower does not have access to a magnifying tool, the old school “red hair” method can be used to determine when to harvest. As the pistols on the flowers mature, they change from a white color to a reddish brown color. Before the days of using magnifying tools to determine maturity, it was common for growers to harvest when the majority of the pistols on the marijuana flowers became red.

Flushing

In order to remove excess salts from the medium and the plant, a grower should implement a flush during the last week or two of the flowering stage of growth. This can be somewhat difficult to time out if experimenting with an unfamiliar strain. For most strains, the flush would begin at the end of the seventh week of flowering. There are many different flushing agents available for purchase. Each product is a little different so be sure to follow the manufacturer’s directions. Another approach to flushing is to simply stop feeding the plants any fertilizer and instead provide only pH balanced water for the remainder of the plant’s lives. Marijuana plants that are not properly flushed can become a finished product which contains residual salts. This will adversely affect the flavor of the finished product and its marketability.

Wet vs Dry Trimming

After patiently waiting for the plants to mature and properly flushing, it is time to start cutting the plants for harvest. First things first, all the large fan leaves should be removed from the plant. At this point, the grower must decide whether he or she wants to trim some of the leaf material remaining around the flowers while the plant is still wet or wait to trim until after the drying process is completed. The biggest advantage of wet trimming is that it can be done more quickly than dry trimming. This is assuming the trimming will be done by hand. We’ll get to automatic trimmers in a minute.

The reason why wet trimming is faster is because the majority of the plant material intended to be removed is perpendicular to the flowers. This makes it easy to access and trim with a scissors. On the other hand, when the plant material is completely dried, it becomes stuck to the flowers and takes a little more time to remove (when done by hand). Many hobby growers still rely on trimming by hand, while many commercial growers use machines to automate at least a portion of the harvest. Ultimately, a grower needs to make the choice as to which method will work best for him or her.

Drying

The drying process is the process in which the plants are hung up to be dried. Most growers will simply cut the plant into sections that are easy to manage and hang them upside-down on a series of strings or wires. The temperature and humidity of the drying area are the keys to a successful drying process. The ideal temperature for the drying area is 65-75 degrees F. The ideal humidity for the drying area is 45-55 percent. It is also important that the drying process is done in the dark. When done correctly, the drying process should take about 6-12 days. The branches and/or stems snapping instead of bending is a good indicator that the drying process is complete. At this point, it is time to remove the buds from the stems, do a final manicuring by hand, and begin the curing process.

Trim Machines

Trim machines offer automation to one of the most tedious tasks in marijuana horticulture: the trimming process. Trimming large amounts of marijuana can be time consuming and costly. Trim machines are devices in which cannabis flowers are automatically trimmed. Most of these devices require the flowers to be dried. It is important to know that not all trim machines are created equally. Some trim machines operate at radically high RPMs, which not only creates a lot of noise, but can potentially damage the quality of the finished product. The better trim machines emphasize gentleness and put quality at the top of the priority list. The better trim machines are also easy to dismantle and clean for quick and effective maintenance.

Curing

As previously mentioned, after the drying process the flowers should be removed from the stems for the curing process. The curing process is essentially the grand finale of the harvest process. During the curing process the flowers continue to dry (very slowly) and their flavor is enriched. A good or bad cure can make or break an entire harvest. Most hobbyists rely on glass jars for the curing process. Each jar should be filled with dried and manicured cannabis flowers to around 3/4th full. These jars should then be stored in a cool, dark place where they can be examined daily. For the first week or two the jars should be opened (“burped”) once or twice a day. This lets out some of the built up humidity and lets in some fresh air. After the first week or so, the jars can be opened less frequently (anywhere from once a day to once every other day). After a couple of months the curing process is complete and the marijuana should be at its peak flavor.

Long-term Storage

Like other dried herbs, properly dried cannabis can be stored for years and still retain flavor and quality. Many growers looking for long-term storage solutions choose glass containers. There are also some manufacturers that make specialty containers specifically for cannabis storage. These containers help maintain ideal humidity levels and protect the marijuana’s quality. Long-term storage of cannabis is best achieved in a cool, dark place. It is also important to leave the storage container undisturbed as much as possible as jostling will diminish the quality.

Trim Material

After trimming cannabis flowers, a grower will be left with a pile of left over trim material. This material can be easily converted into usable extracts. Edibles and/or smokable concentrates can be easily made from trim material with little more than household items. A quick search on the internet can provide detailed instructions to growers on how to turn trim material into usable products.

There is a world of difference between marijuana that was properly grown, flushed, dried, and cured and marijuana that was not. Higher quality and more flavorful marijuana is not only more enjoyable for the grower, but is also more valuable on the market and is, in turn, more profitable. After all the time and labor invested into a marijuana growing operation, it makes no sense to have a poorly conducted harvest. In fact, the harvest is the holy grail of the flowering process and the entire marijuana cultivation process. It is ultimately the prize sought after by anyone who has ever decided to grow cannabis. Take each harvest as an opportunity to expand your knowledge and fine-tune your trade. As with other aspects of growing cannabis, becoming a master of harvesting comes with much experience and experimentation.

Eric Hopper is a contributing editor.