Marijuana smells amazing! We all know that… the thick aroma of the grow room, the pop of air from the curing jar, the hot, thin smoke wisping from a spent bowl… this is heaven for cannabis fans. But why does marijuana smell? Do fertilizers and nutrients affect the smell of marijuana? How much is down to the grower? What can cannabis growers do to improve the taste and smell of marijuana? To answer these questions, you need to understand terpenes and how to increase the terpene production of your cannabis flower.
How do terpenes affect the smell of weed?
Along with THC,CBD, and other cannabinoids, the glands in trichomes also secrete a diverse class of organic compounds called terpenes.
These are the aromatic oils responsible for the fragrance and flavors of marijuana plants, especially the flower. The most widely recognized scents – earth, citrus, berry, skunk and others – are all due to the presence of different types and concentrations of terpenes.
To date, more than 100 different kinds of terpenes have been found in marijuana plants. They can repel pests and predators, they can attract pollinators, they can make your plant smell more skunky or more chemmy, and, more importantly, they’ve been connected to many of the medicinal and recreational qualities of good-quality, high-grade marijuana.
The sensual and physical effects of marijuana are difficult to explain. They’re produced by the interplay and synergy between phytochemical compounds, coupled with our unique and changing endocannabinoid systems. Terpenes play a major role in this, which explains why, for example, a strain with a rich terpene profile can feel more intense than a strain with higher THC but fewer terps.
Cannabis growers and breeders can enhance the quality of the buds by maximizing the concentration of terpenes in their plants, during cultivation AND during the cure, but how?
What can cannabis growers do to improve the taste and smell of marijuana?
To maximize flavor and aroma you need more terps and purer, less-contaminated cannabis. These are the main areas you should be focusing on: increasing terpene concentration, avoiding bad practice, storage and curing. As number one on this list is the most important, let’s jump straight in.
1. How do you increase terpene production in cannabis plants?
There are six good ways to increase terpene levels through your marijuana grow cycle. From physical manipulation to nutrient choice to light spectrum. As with most growing techniques, they need to be applied as part of a holistic, encompassing strategy. It’s no good maintaining humidity, airflow and temperature (HAT) if you plant your cannabis in clay and never feed it. You need to be conscientious with all aspects of your grow for the best chances of success. If you can choose the right soil while using gentle LST, the correct light spectrum, good nutes, balanced HAT and a good flush, you should be well on the way to terpene heaven!
Here are our six ways to increase terpene levels throughout your cannabis grow cycle:
Using living soil to boost terpene levels in cannabis
Growing with organic soil (as opposed to hydroponics) delivers cannabis with a better terpene profile than its watery counterpart. Living soil, in particular, is preferred by discerning master breeders and growers like Homegrown Cannabis Co. resident genius Kyle Kushman.
Living soil teems with beneficial microorganisms. This soil-food ecosystem is self-sustaining and a symbiotic relationship exists between plants and microbes. Microbes feed on plant waste while producing or gathering ready-to-use nutrients, allowing plants to grow.
Growing marijuana organically is the best way to ensure the buds are fragrant and clean. You could go even further and switch to veganic gardening: using plant-based nutrients free from any animal-feed or heavy metal contamination. This philosophy and practice is at the core of Kyle Kushman’s success as grower, breeder and teacher.
Using Low Stress Training to increase terpene levels in cannabis
Low-stress Training (LST) refers to techniques like Sea of Green (SOG) and Screen of Green (SCROG). LST is a way of physically manipulating the branches and stems, usually through a screen or mesh, in order to expose more bud to light. The surface area capable of collecting photons increases massively, leading not only to heightened terpene production, but higher concentrations of THC, CBD, and other cannabinoids. Yields also improve significantly.
Using nutrients to boost terpene levels in cannabis
Cannabis plants consume more nutrients as they grow, so giving the right amount is vital. Key to elevated terpene production, however, is the type of nutrients you give them. Using Veganic (or, at least, organic nutrients) is by far the better choice. Organic compounds, such as those derived from kelp, bone meal and worm castings, break down and do not leave toxic residues. During the last weeks of the flowering stage, you can try blackstrap molasses to provide carbohydrates, amino acids and minerals – all of which improve terpene production.
For most strains, you generally reduce nutrients into the sixth week of flowering, giving just enough for the plants to grow. The reduction of nitrogen especially stops buds developing a harsh smell and taste.
Using UV-B light to improve terpene levels in cannabis
For those unable to budget for high-output, full spectrum LEDs, the go-to lamp for flowering cannabis is the traditional High Pressure Sodium (HPS). While the HPS does a fine job (albeit hot and wasteful), your terp levels could be boosted further by using a UV-B light, too.
It is believed this type of light can help increase the production of trichomes, which means more glands to secrete terpenes. The plants produce more trichomes to protect themselves from the UV-B light – which is great news for your cured bud!
Using humidity, airflow and temperature (HAT) to raise terpene levels in cannabis
Staying within the ideal temperature and humidity range through the growth stages is essential to overall health. During the sixth week of flowering, keep the temp under 80°F with good airflow inside the tent or grow-room. Terpenes are volatile and will denature when exposed to high temperatures.
During periods of darkness, you can boost terpene production by dropping the temperature by 5-10°F. This also has the additional bonus of triggering those amazing blue and purple hues in strains like Blueberry and Grandaddy Purple. It’s best to do this only during the last couple of weeks of flowering.
Throughout the flowering stage, try to maintain an average humidity level of around 50% RH. During the last two weeks, it can be brought down to 30%. Keeping good moisture levels not only prevents bud rot but also boosts the production of trichomes – those amazing terpene machines.
Flushing cannabis plants to boost terpene levels
If you’re using regular soil mix, you should flush 1 to 2 weeks before harvest. This reduces the residual nutrients absorbed by the plants, resulting in cleaner, smoother buds. Cannabis without impurities is cannabis at its best.
If you’re using coco or hydro, then flush a few days before harvest. You don’t need to flush if you’re using supersoil.I
2. Avoid bad practice, boost your terps!
As harvest looms, your plants enter a critical stage of their life cycle. Anything that might ruin your buds or degrade cannabinoids and terpenes should be avoided.
When to harvest and how to harvest for terpenes
Timing is everything. Harvest too early and your buds will lack fragrance, flavor and potency. but also in potency. Harvest too late, and your cannabinoids and terpenes will have started to degrade.
Drying and curing for terpenes
Trim the buds on their stems and hang your plants whole and upside down. This gives the buds a water buffer, making it easier to dry slowly. A steady drying rate means more terpenes are preserved.
To preserve the maximum number of terpenes, the drying room should be kept at 60-75°F. You could try a few degrees below this range, but you need to be careful not to create a good environment for mold. 70°F is the optimum agreed by most growers, balancing terpene preservation with mold avoidance.
Keep an eye on the moisture level, too. If the humidity level falls below 40% RH, the buds are going to dry too fast. If it exceeds 60% RH, molds may develop. You should maintain 50% RH for optimum terpene preservation.
You know the buds are dry enough when instead of bending, they snap off the stems.
When filling your mason jars, fill to around 80% capacity. Keep an eye on the moisture level, – around 60-65% RH is great for cannabis storage and curing. Open the jar daily during the early stage of the cure. After a week or two, you can open the jars every few days and gradually progress to once a week.
At first, the buds will smell like grass or hay. After a few days, though, the rich smells of marijuana will start to intensify. If you get a whiff of ammonia, your cure is probably over. Ammonia is an indicator of bacterial growth. You could try leaving the jars open for an hour before sealing again. Inspect the next day again and if the ammonia has gone, you’re in luck.
3. Preserve the terps
Once your buds are nicely cured, keep the jars in a cool, dark place. The more light that penetrates and hit the buds, the more it degrades.
Learn advanced techniques to increase and preserve terpenes
Beginner growers should stick to the basics and practice, practice, practice. Don’t try to run before you can walk and remember, one good crop does not a master grower make. Once you have a few successful harvests under your belt, you should start experimenting with some advanced techniques. SCROGs are a good place to start – pretty soon you’ll be supercropping every grow with the skill of a Kushman!