Terpenes are chemical compounds found in the essential oils of cannabis plants and are responsible for each individual plant’s unique odor and flavor profile. The aromas that fill the air when a marijuana bud is pinched or a jar of freshly cured flowers is opened can be attributed to the terpenes. In nature, plants create terpenes for three reasons: to attract pollinators, to repel hungry animals or pest insects, and to attract beneficial insects or predatory animals for protection. Most plants, including cannabis, increase their terpene production as they mature. In other words, as they get closer to reproduction, more energy is invested in attracting pollinators or to protect themselves. Cannabis plants are wind pollinated. This means their terpenes are not made to attract pollinators but rather to protect themselves from animals or pest insects looking for lunch. As a cannabis plant reaches the end of its flowering stage, the terpenes are at their maximum content. Considering that terpenes are what essentially give each cannabis plant its unique flavor and odor, it should come as no surprise that horticulturists use products and techniques to specifically target maximizing terpene production.
Nutrient Additives for Terpene Production
There are many nutrient additives on the market designed to enhance the flavors or odors of cannabis plants, and most of these target terpene production. Many of the flavor-enhancing products are carbohydrate-based, meaning they add sugars to the root zone to enhance the microbial population and give plants access to more carbohydrates. Many of these enhancers also contain amino acids, another component that contributes to the overall health of the plant. There are also nutrient additives that are a little more specific for terpene production than the carbohydrate-based additives. These additives utilize naturally occurring plant compounds known as bio-osmotic potentiators, which encourage plants to enhance their terpene and essential oil production.
Many flavor and terpene enhancers are compatible with a normal fertilizer regiment. However, there are some flushing products made to increase flavor and terpene production that are designed to replace a fertilizer regiment. Carefully read the directions of any flavor enhancer or flushing agent to find out how it should be used.
The last few weeks of the flowering stage are crucial times for terpene production. As stated above, a cannabis plant creates terpenes to protect itself and increase its chance of successful reproduction. Hence, it’s during the later stages of flowering that the plant expends the most energy on producing terpenes. Regardless of whether a flushing product is being used or not, a cannabis grower should reduce or alter his or her feeding regiment during the last stages of flowering. Most of a cannabis plant’s terpenes are found in the flowers or buds. Certain elements, such as nitrogen, are known to slow down flower formation, which, in turn, would reduce the production of terpenes. So, a balanced feeding regiment with a reduced amount of nitrogen should be used during the flowering stage. It is also important to eliminate nitrogen from the feeding regiment during the final two weeks of flowering.
Growing techniques for increasing terpene production
In addition to providing them with a carbohydrate formula, a terpene-specific enhancer, and/or a flushing product, the most effective way to increase terpenes is to lightly stress the plants during the flowering stage. Slightly inducing stress in cannabis plants can be done a few different ways. Just keep in mind that deliberately initiating stress is a fine line to walk and, although the benefits can be great, it should always be done cautiously so as not to over-stress the plants. The goal is to stress them just enough to boost terpene production but not enough to cause any serious harm.
One simple way to lightly stress a cannabis plant is to pinch some of the branches. By simply taking the stem between the index finger and thumb, then pinch firmly. Branches can also be bent or manipulated to change the direction of growth. This technique serves two purposes: first, the stress will increase the production of terpenes and, second, a grower can reposition branches to allow light to reach areas that were once shaded.
Undercutting your cannabis plants
Undercutting is another great way to fulfill two needs with one deed. Undercutting involves removing leaves from the lower section of a plant where they are shaded and do not receive much light. By removing these leaves during the flowering stage, a grower can redirect much of the plant’s energy into producing flowers at the top of the plant. Undercutting also creates enough stress in the plant to increase its natural terpene production. Novice growers should experiment with their particular strains before excessive undercutting as removing too many leaves can over-stress the plant and reduce the yield significantly. Never remove more than one-third of a cannabis plant’s vegetation at one time.
Temperature for maximizing terpene production
The high temperatures from artificial light sources can damage terpenes and essential oils. This is one reason why it is recommended to lower the operating temperature of a flowering room during the last couple of weeks of flowering (peak terpene production). Generally, the optimal operating temperature for growing cannabis is 75-80˚F. During the last couple of weeks of flowering, some growers drop the temperature range by 5-10 degrees Fahrenheit. This reduction in temperature slightly stresses the plants and increases terpene production while protecting the terpenes from being damaged by excessive heat. Just be sure the temperature doesn’t drop too low or there is not a differential of more than 10 degrees Fahrenheit from the light and dark periods. Operating temperatures below 60˚F can be counterproductive and reduce yields. Also, a large temperature differential between the light and dark periods could cause condensation and/or humidity related issues.
Humidity for maximizing terpene production
Ideally, the humidity level in a cannabis flowering room would fall between 50-60 percent. However, during the last few weeks of flowering, the humidity level can be dropped to around 30 percent to slightly stress the plants. This usually requires a dehumidifier. The lower humidity lightly stresses the plants which, in turn, increases terpene production. Lower humidity during the last weeks of flowering also reduces the likelihood of molds and other humidity-related problems.
Perhaps one of the most influential factors over the concentration of terpenes in cannabis is the timing of the harvest. Cannabis plants that are harvested too early have not yet reached their maximum potential in terpene production. Also, drying a harvested cannabis plant too quickly also alters the terpene profile. To get dried cannabis flowers that retain the unique odors of the plant while it was growing, the cannabis must be dried slowly (especially for the first few days). When done correctly, cannabis plants should take anywhere from seven to 14 days to dry before they are placed in long-term storage containers to cure.
Terpenes found in cannabis
There are many different terpenes commonly found in cannabis plants. These terpenes influence each plant’s unique characteristics. The following are just a few of the sought-after terpenes.
Myrcene is a terpene found in cannabis, hops, and lemongrass. Odors associated with myrcene are citrus, nut, earth, and clove. Specific odors will vary due to slight changes in the overall make-up of the essential oils. Medicinally, myrcene has pain relief and antibiotic properties. It’s possible myrcene combined with tetrahydrocannabinol (THC) causes a more intense high as myrcene is thought to help THC reach the brain cells more easily and effectively.
Pinene is a terpene we are all familiar with because it is associated with the fragrance of evergreen trees. The pine tree smell found in some cannabis varieties is attributed to pinene. It is also believed that the skunky smell of certain cannabis plants is caused by pinene. Medicinally, pinene can be used to treat coughs and can be used as a topical antiseptic.
Limonene is a citrus-specific terpene and is found in the rind of citrus fruits. Hence, a strong citrus smell in cannabis flowers is most likely created by the presence of limonene. Medicinally, limonene has antibacterial and antifungal properties. Limonene also shows potential as a treatment for depression.
B-Caryophyllene is the terpene most associated with black pepper. Cannabis strains with a spicy or woody-spice odor are most likely exhibiting their B-Caryophyllene content. This terpene has medical potential as a topical pain reliever and inflammation reducer.
Many different terpenes contribute to a single cannabis flower’s unique odors and flavors. This is one reason why there is such a range of cannabis varieties. Atmospheric conditions, the nutrients used, and the way a grower harvests his or her flowers also directly influence the terpene profile of a plant. The fact terpene production can be promoted by specific products and techniques further illustrates how every garden can produce a slightly different product. So, even when two horticulturists grow the exact same strain, there are usually slight differences between the finished products. The more a cannabis grower understands terpenes and how to promote them, the more likely he or she is to produce the most odoriferous and delicious buds on the block.