Increasing Cannabinoid and Terpenoid Test Results

So… the only real data that I’ve seen for increasing potency comes from increased light intensity, particularly UV. However, there are so many speculations out there on other methods as well such as decreasing macronutrients near the end of gestation for increased terpenoid content, or dehydration for increased THC.

What trials have you done? What do you feel actually works? Has anyone tried changing light spectrum towards blue and/or UV for the end of flower? What about defoliation at the end of flower to expose flowers to light? How about manganese for increased THC or other foliar or nutrient applications?

Anyone performed any controlled trials on any of these techniques where you at least did a side by side?

Canopy management is huge, especially indoors, as is general light intensity. However, nothing we’ve trialed has compared to the difference just having good genetics makes, but I’d love to hear from anyone that’s really tried some of this stuff.


Hi Cody,

The last data I received from a commercial comparison using our new nutrient line (Key Grow Solutions) was from an individual by the name of Will Kuss with a cannabis brand called Heady (they are affiliated with the CBD brand Leef Organics as well). He reported that in the comparison, terpene profiles increased from 3.2% to 4.3%.

In large part I attribute this to the use of potassium acetate as our potassium source. Acetate is a natural plant metabolite that, according to my chemists, is associated with the production of fatty acids, sterols, phenolic acid, flavonoids, amino acids, chlorophyll, caretonoids, terpenes, etc. Although I’m sure other factors play into it as well.

While I know a lot less about the lighting effects on terpene production, a fellow by the name of Bob from Green Fusion LED in Oregon showed me test results that showed me they had hit 4.6% terpenes using their lights. Needless to say, I am going to send them some samples to see if the two combined make any sort of difference. If you are savvy about lighting spectrum and technology, you may find some answers if you review their tech.

Perhaps not as technical as you are looking for, but hopefully it helps a little.


So there are some scholarly articles that indicate that as Joel says you may also be able to increase these from nutrient loading. Here is one that discusses the precursors to THC synthase, which contribute to terpene production - it talks about a lot of other things so don’t mind the clutter and also has some excellent references to previously conducted studies for about 11 of “big” terpenes.

Here’s another one that really gets into the discussion of the major terpenes - their individual chemical pathways. It also says that the production of terpenes per plant is so highly variable, that specific nutrient and light campaigns may have no impact. And then there’s a large discussion about genetics - which you have already mentioned.

There is an entire study of science for how terpenes are generated in as a defense mechanism for the plant against pests, micro-organisms, weird weather, and the like. So the direction you are going there seems to be quite fine.

From my personal experience - I have found that plants grown outdoors and then transferred indoors for finishing had a higher level. This is anecdotal of course, since I didn’t try with the same plants just inside and just outside - and my personal study lacked any kind of rigor. :frowning: But there is some scholarly work around this for all plants, not just cannabis.

Probably you have already read these items - from what I can see you should provide the appropriate nutrients and then put the plant in a stressful (but not completely deadly) environment. I’d love to do some experiments like this - but I fear people would like to stay with things tried and true. And my personal grow is just four plants at a time, which would take years to collect the data. The last article does discuss switching up the kind of UV that is used - so perhaps the new fancy lights Joel mentioned would do the trick.

Its also probably worth noting that the same nutrients and many of the same synthase pathways are used to make THCa - so you may also be looking at competition between these two pathways.

Good luck - and please let us all know if you find anything interesting or start doing experiments. Just now I’ve pulled my “sun” plants into an LED full spectrum, temp/humidity controlled grow house. I expect similar results from last years fall to winter crops - and I’ll try to remember to let you know in a month or so.


From what I can tell, both CBGa and essential oils are from the same precursor called Acetyl Coenzyme A. Terpenes are just one of the essential oils that add to the effects and flavors of the plant. Some of the others are esters, aldehydes, phenols, lactones, sulfides, and probably others as well. There are ways to encourage the plant to produce high amounts of Acetyl Coenzyme A (such as acetate), but other mechanisms may be able to manipulate the plant into producing desired resins.

I do not have references for this I apologize, but I have been hearing a school of thought that the resin production is a scale. In other words, perhaps your plant is capable of producing up to 40% resins. Within that capacity, that 40% can either be cannabinoids or essential oils. This is why sometimes a plant with a low terpene percentage may still smell or taste great. You may have 15% THC and 1.5% terpenes and perhaps there is a large amount of other essential oils.

I would be curious if anyone else has heard this and what their thoughts might be on the matter. Please do not jump on me if the science is off, that’s why this is a discussion. :wink:


My most recent operation placed Research and Development at center with all other elements looking inward. This continued over a two year period and included indoor, outdoor, and greenhouse - inorganic and organic. Regarding the topic: Testing was conducted as each additional step was introduced. This showed in live time the evolution of my practices which I found interesting - as I introduced each additional component in the same order the practice was adopted. Finally, I tested additional steps and creative ideas. General items or measures intended to increase expression were blended in to a simplified SOP and calendar. The more advanced information and nuances were retained by me in my ‘Program Notes’. Below I will state the basic procedures I use to increase / protect the content of the flowers proven objective by a clear linear uptick in every metric [substantially so]. I have to admit that I am pretty proud that most of this was sorted using my senses and observation without access to labs. The labs just proved I am not a crazy person.

In observing one area of your post: Overall, the terms people are often looking for include SAR [Stress Acquired Response], ISR [Induced Stress Response], Biotic Stress [stress caused by an organism], Abiotic Stress [stress caused by a non living entity], and within these categories exists a glossary [and a lot of studies]. Using those keywords help navigate this topic [of stress and effect].

I will not be citing / sourcing or providing much explanation. I find this a good practice when clarity is needed. My level of confidence in the simple version of this routine is absolute. There were no circumstances in which positive results were not seen. I assume education isn’t much needed but will leave some information for people that come later or are just curious about this post [but might not be a cultivator].

Some of this will include previously covered information in the post. That is simply intended as further confirmation [aiding confidence].

Pre/Harvest: Remove all non producing leaves and underdeveloped portions of the plant 48 hours before harvest. Reduce the intensity of the light. Do not allow 72 hours to pass. Make sure the soil remains damp but at the lower end of acceptable saturation [60 mbar]. Harvest during photoperiod two hours before the plants circadian rhythm awakens the plant [and before the lights come on].

Insects and Lifeforms: Quick brewed Insect Frass Tea [2-2-2] applied at the fifth and sixth week of flower. Adjust nutrient program to accommodate. The Insect Frass should be applied lightly [it is a longer duration, specific response in terms of SAR, but fast release in terms of a nutrient, and if you freak the plant out enough it will give you an innersex reponse]. Complete this illusion for the root system using beneficial lifeforms that will interact such as Worms, Nematodes, Springtails, Rove Beetles, and Stratiolaelaps Scimitus. Utilize an IPM program above ground that includes active species such as predatory mites. Adding LAB [Lactic Acid Bacteria] to increase microbial activity is advised [See Korean Natural Farming for instructions on culturing LAB or use products such as EM-1].

Drought: Hormonally cascading [less is more]. Drooping only needs to occur for a short duration [3-4 hours and no more than 6]. Overwater at first application and return to normal [100 mbar]. Lower any additional nutrient inputs at first application by 25% [if applicable]. This is done a total of three times [and no more]. At the first sign of flower, at the exact midpoint of flower, and at the beginning of the final week of flower. Schedule routine defoliation / dead-leafing 72 hours post these events.

Lighting: 11-13, 13-11, or 12/12 for the last ten to fourteen days or so is worth the experimentation on any specific plant. Raise the lights or lower intensity for the last 48. If you have LED’s that provide options throughout the rainbow - increase at 380-390 nm and slightly increase the UVB in the last four weeks.

Sound: For the last week of flower play a recording in your grow room that contains the amplified sound of insects feeding on plant matter. Twenty minutes at a gentle volume twice daily [daytime / nighttime]. I used noon and midnight [so I didn’t have to listen to it and could just leave for lunch]. This is besides the fact your plants should have their own bangin’ play list!

Sulfur and Sodium: A slightly higher than normal / required PPM of sulfur. A slightly higher than normal / commonly accepted PPM of sodium.

Potassium Salts of Fatty Acids: Applied weekly through the entire process. MPEDE is commonly allowed. This is done as a foliar [commonly used for mold suppression].

Nutrients / Other: Joel is correct. Acetate can be added for beneficial results [but I did not specifically add this to my program and have not measured the result. I do use vinegar which impacts the pathway]. Malted Barley placed sparingly around the stalk or scratched in to the surface of the soil - starting one week before flower induction and replaced every two weeks until harvest. Make sure nitrogen has not been dramatically reduced. Make sure calcium has not been dramatically increased. Add diluted sea water and water soluble kelp extract at week five of flower [if you do not have access to sea water products exist that are concentrated from sea water]. There are other recommendations but they are commonly explained. This should all [again] be considered in conjunction with your already existing program.

Trichomes / Timing: Check trichomes for ripeness. Mark the obvious date [when everything is nice and milky]. Harvest one week before and after that date and compare the results. This isn’t always helpful [it is always helpful to truly dial in that magic moment] but in some cases where more or less maturity might help [usually for CBD or ‘balanced’ strains with notable combined THC/CBD levels] or if a specific effect is desired [CBG vs CBN for example]. Really, the problem is that if you do not provide the same conditions and harvest at the same exact time every time - your data will reflect the inconsistency as opposed to the true result.

Temperature: Reduce temperature in the last week. You will need to play with this and discover what works for you in your environment but generally a decrease of 7-10F. I have been told by several people over time that high temperatures [such as 90F] with high humidity [over 70%] will force the plant to express its resin glands rapidly [to the point it is ‘dripping’ with resin after a while]. I haven’t tried that myself but if you want to conduct a small experiment to see what happens - might be fun.

pH: Be mindful of the pH of anything you foliar with during flower. Use vinegar as your acid / pH solution [something organic that doesn’t start with petroleum in the manufacturing process]. Do not use vinegar for foliar [just a side note for clarity]. Do not use vinegar just before entering a drought cycle.

Suicide Methods [and somewhat an alternative]: Infect yourself with Thrips for the last two weeks of flower - left untreated [and foliar with Cease, for example, or LAB, at the same time]. Different infections will give you different results. Another method is to pollinate the crop late enough in flower that seed production is extremely limited [this will alter things. Play at your own risk]. This is of course a bad idea in a perpetual grow [lol]. Just a random note.

Stranger Things: The plant will not simply ‘uptake’ terpenes from the roots. However, you can slice the stem a few inches below the flower, dilute stable terpenes extracted from a Cannabis plant [or perhaps hops], and allow the terpenes to be drawn through. This, again, is just a note, it isn’t anything I would prefer to do myself. Fermented Fruit Juice can make an impact [See: Korean Natural Farming] on flavor as well.

As far as adding precursors - such thoughts exist in my ‘Program Notes’ and is a different conversation for a different day. I can tell you that the majority of the notes simply read, “no” [for various reasons]. Acetate however is absolutely on the greenlight list. I find that proper care, some additional stress applied properly, and good genetics are best practice. I excluded from this every experiment [many] that I tried in addition, etc, this seems to be the way to go. I am sure there are other methods for me to consider, still, but usually that results in needing to make other adjustments.

Hopefully you found some of this useful.