Introducing the P-Sol Flowering Cycle Methodology

For decades, cannabis cultivation has operated under a simple assumption: flowering takes eight to twelve weeks, and there is little anyone can do to change it.

Lighting technology has become more efficient. Environmental controls have become more sophisticated. Genetics continue to improve. Yet one constant has remained: the biological clock governing vegetative growth and flowering.

At Black Dog Horticulture Technologies & Consulting, we began asking ourselves a question:

What if we stopped designing lighting schedules around Earth's 24-hour solar day?

That question led to years of discussion, planning, and ultimately experimentation. The results surprised even us.

Our initial research demonstrated that photoperiod-sensitive cannabis can complete flowering approximately 25% sooner under a shortened light/dark cycle while producing flower quality and quantity comparable to conventionally-grown control plants.

That's two full weeks removed from a normal 8-week flower cycle.

"Diva" strains that normally require 12 weeks could be harvested in only 9.

If these results continue to scale commercially, the implications extend far beyond shorter flowering times. They could fundamentally change facility design, production planning, electrical utilization, breeding programs, and annual profitability.

This paper explains what we discovered, why it appears to work, and where we believe this research could lead.

In short, we believe we've uncovered a cultivation methodology with the potential to reshape how commercial facilities think about flowering, and we'd like to help determine what aspects of this methodology make sense for your unique facility.

Two Weeks Changes Everything

Removing fourteen calendar days or more from every flowering cycle doesn't simply shorten one harvest.

It could change the economics of entire facilities.

If this approach ultimately proves commercially viable, it could provide your facility:

• More annual harvests
• Better utilization of expensive cultivation facilities
• Improved cash flow
• Higher ROI on cultivation infrastructure

So, how does it work?

Re-thinking a Long-Held Assumption

One of the more empowering aspects of being an indoor cultivator is controlling the daily light cycle of plants to manipulate their vegetative and flowering phases. As cannabis growers are aware, giving the plants 16-24 hours of light each day maintains vegetative growth. Switching to a 12/12 cycle with 12 hours of light and 12 hours of darkness initiates flowering.

But each light/dark cycle still adds up to 24 hours.

Over 12 years ago, during one of our many discussions surrounding lighting and plant physiology, Kevin Frender- Black Dog Chief Science Officer and life-long plant geek with over 45 years' experience growing indoors- proposed a deceptively simple question:

Does flowering actually require a 24-hour day?

The question sounds almost trivial.

It isn't.

Photoperiod-sensitive plants don't measure the length of daylight to determine when to flower. They measure the duration of uninterrupted darkness, and once this reaches a critical threshold, hormonal changes trigger flowering.

Since darkness and not total day length is the true biological trigger, what if we provided the critical 12-hour dark period, but shortened the illumination period to create a less-than 24-hour "day"?

That single question became the foundation of everything that followed.

Geeks Love a Good NASA Name

Very quickly we ran into a language problem: using the term "day" when discussing this idea quickly becomes confusing. We often use the word "day" to refer to a 24-hour period, but also to the daylight portion of that period.

To avoid similar confusion when coordinating schedules on 2 different planets, in 1976 NASA scientists coined the term "sol" to refer to the 24.66 hour long solar day on Mars.

Borrowing from that, we adopted the term Plant Sol (P-Sol) to describe any repeating light and dark cycle that is not 24 hours long.

The Science Behind Our Theory

Plants' cellular metabolism and division are at least partially governed by their circadian rhythm: a natural, roughly-24-hour cycle, which itself is continually synchronized to their environment by exposure to light and darkness- the "circadian clock".

This gets rather complex and is outside the scope of this article, but if you would like to learn more on how this works, search for information about phytochromes and cryptochromes- as plant geeks we find this stuff fascinating.

If it was possible to continuously re-synchronize the circadian rhythm to a less-than 24 hour cycle, it may be possible to accelerate plants' metabolism and cellular division, ultimately speeding up growth and maturation.

Once you wrap your head around the idea, you quickly realize that running 6 hours illuminated and 12 hours of darkness for cannabis could cut 25% off the time it takes to complete a regular flowering cycle- if it worked. Essentially, every "day" for the plants becomes 18 hours long instead of 24- hopefully accelerating their growth and maturation compared to natural days.

When we first thought of this we naturally explored existing research.

The only study we found that tested a non-24-hour clock cycle was from Dodd AN, Salathia N, Hall A, Kévei E, Tóth R, Nagy F, Hibberd JM, Millar AJ, and Webb AA in 2005¹. Rather than examining the effects of non-24-hour cycles on photoperiodicity, this experiment focused on aligning individual cultivars' natural genetic circadian rhythms with a similar-length P-Sol.

The study identified cultivars of Arabidopsis thaliana, the "lab rat" of botanical research, that naturally had circadian rhythms of 20 hours, 24 hours and 28 hours when the rhythm was not being reset by the circadian clock. Then they exposed each of the 3 identified cultivars to 10/10, 12/12 and 14/14 hour schedules: a 20-hour P-Sol, normal 24-hour day, and a 28-hour P-Sol.

Their findings indicated that cultivars performed better when given light/dark cycles matching their natural circadian rhythm.

That result has interesting implications of its own, but this study did not answer our question as to whether photoperiod-sensitive plants can perform with an altered light and dark cycle designed to re-align their circadian clocks and rhythms. It only indicated that cultivars naturally aligned with a shorter-than and longer-than 24-hour P-Sol performed better when their default circadian rhythm aligned with the photoperiod provided.

We're aware of many other research studies exploring non-12/12 flowering schedules for cannabis, for example using a 13/11 schedule to increase yield. But these are still using a cycle that repeats every 24 hours.

P-Sols are divorced from a 24-hour cycle completely.

The Challenges

Initially, our largest question was if it is really possible to trick a plant into accelerating its metabolism and maturation by using a less-than 24-hour P-Sol, which only experimentation could answer.

But there are real-world challenges to running a P-Sol schedule.

Biological and Engineering Challenges

There is a change in environmental needs. Most thermostats and other environmental control gear are firmly based on 24-hour days. Cycle timers, such as those used in hydroponics, can run a simple repeating cycle for lights, but HVAC and related equipment is more difficult to control.

As lighting experts, we recognized that with a reduction in the duration of the lights-on period, the DLI (Daily Light Integral- the total amount of light given to plants in a day, or in our case a P-Sol Light Integral or PLI) would drop. To offset this and avoid a reduction in yield, a commensurate increase in the light intensity is likely necessary. For example, if you were running 1000 PPFD with a normal 12 hour flowering light cycle, you would need to provide 2000 PPFD to attain the same DLI in a 6 hour period. For those unfamiliar, PPFD (Photosynthetic Photon Flux Density) measures the immediate intensity of light on a crop and is usually measured in the number of photons (in micromoles) in the 400-700nm range going through one square meter each second, expressed as μmol/m²/s.

However, light intensity cannot simply be arbitrarily increased- 2000 PPFD under high pressure sodium lights would quickly burn the leaves.

The light spectrum matters here, as some spectra heat leaves up much more than others. We published research on this over 12 years ago while we were perfecting Black Dog LED's spectrum, showing how different spectrums affected leaf surface temperature. We have since run research cannabis grows with our spectrum at over 2600 PPFD with almost no bleaching or other negative side-effects. This spectral tuning allowing extreme light intensity without harming plants is a key to accelerating the plants' metabolism in shorter-than 24-hour P-Sols.

Yet another issue with lighting is the physical size of fixtures. Most existing LED "bar lights" simply cannot provide 2000 PPFD average illumination over an area the size of the fixture, and they cannot be "stacked on top of each other" without blocking light, overheating the fixture, or both. Black Dog LED's compact, actively-cooled PhytoMAX-4 lights can be deployed to achieve intensities exceeding 6000 μmol/m²/s average PPFD, enabling tests with extreme illumination.

But, if the biology of P-Sols works, the engineering problems can be solved. That's exactly what Black Dog HTC has spent years doing.

Practical Challenges

The final major challenge is purely practical, but potentially a deal-breaker: a non-24-hour cycle can lead to days where the lights are not on during normal working hours. Having run plenty of grows ourselves, and with 16 years' experience consulting on commercial facility workflows, labor-balancing, and power-balancing, we knew this could create a nightmare for commercial growers.

An oddly-offset non-24-hour schedule could also cause electrical problems in facilities where flower rooms are "flipped" so that one flower room has lights on while another has lights off to reduce total amperage loads.

But there's one special less-than 24-hour P-Sol that has some unique properties.

The Goldilocks P-Sol

An 18-hour P-Sol could provide the "just right" fit of accelerated harvests and practical scheduling. Having 6 hours illuminated and 12 hours of darkness allows a light schedule that always has at least one hour of lights-on in the room during a normal 9-to-5 8-hour workday.

A visual representation of an 18-hour "Goldilocks" P-Sol Schedule- note that the 56th P-Sol (the equivalent of 8 normal weeks) occurs on the 42nd calendar day (6 calendar weeks).

This 18-hour P-Sol would also allow rooms to be "flipped" not just across 2 rooms but 3: one room with lights on and two other rooms off at all times.

A schedule showing 3 flower rooms "flipped" with each other using the 18-hour Goldilocks P-Sol. Note that the schedule repeats every 3 days, and can be adjusted so that all 3 rooms are accessible during an 8-hour workday.

But cutting the illuminated period in half of the "normal" 12 hours seemed rather ambitious- surely the plants would stress out?

It would also require doubling light intensity to keep the same number of photons nourishing the plants, and under most grow light spectrums plants start burning or bleaching when intensity is doubled to 1800-2400 μmol/m²/s from a "normal" level of 900-1200 PPFD.

But we had already designed and tested our lights' spectrum to run 1800-2600 PPFD without causing plant stress, so providing a normal DLI / PLI for the Goldilocks P-Sol is possible.

Given the "just right" balance of the 18-hour Goldilocks P-Sol, we recognized that this could be the foundation of a very different commercial production strategy.

But only if it actually worked.

We Expected Something to Go Wrong

For humans, traveling across 6 time zones causes jet-lag as it takes our circadian clock time to adjust our internal circadian rhythm to a new day/night schedule. An 18-hour P-Sol is essentially the equivalent of moving the plant 6 time zones at a time, every 18 hours.

Would the plants become stressed?

Would this cause hermaphrodites?

Would yields collapse? Quality?

Yes, research had shown that some Arabidopsis plants didn't suffer when grown with a 20-hour P-Sol, but they're hardy little plants that only live 6 weeks and don't require a photoperiod trigger to initiate flowering. They're kind of like the cockroaches of the plant world.

We've run hundreds of research grows, deployed tens of thousands of lights to home growers, commercial and research facilities, and spent thousands of hours talking with growers of all stripes. We've seen and heard some pretty crazy stuff, but the idea that an 18-hour P-Sol could actually work with cannabis still seemed dubious.

But, having pondered it for so long, we had to find out.

So we designed a series of controlled experiments to test less-than 24-hour P-Sols.

Experimental Set-Up

We set up two tents with ALIEN^® AERO^™ aeroponic pots being fed simultaneously from the same reservoir. This allowed us to ensure that the test and control plants received the same nutrient solution on the same schedule.

One tent served as the control, receiving the standard 12-hour lights-on, 12-hour lights-off schedule (12/12), while the other tent ran a reduced P-Sol concurrently.

Black Dog LED PhytoMAX-4 grow lights provided illumination, with light intensity in the test tent increased relative to the control so that the DLI (or "PLI" for P-Sol Light Integral for the test plants) was the same.

Proprietary software was used to control the light schedule, temperature and humidity in each tent, aligned with the tent's assigned photoperiod.

Clones from the same mother plants were used in both tents to ensure identical genetics, with 4 plants in each tent. The strains used for testing normally ripen in 8 weeks / 56 days, so each experiment was run for that duration. Ripeness was determined by counting relative amounts of milky and amber trichomes.

We specifically looked for issues with flowering initiation or noticeable stress responses such as "herming" (development of male flowers on normally female plants), stunting, signs of nutrient imbalances, or any other noticeable difference between test and control plants.

Initial Proof-of-Concept: a 20-Hour P-Sol

Since we didn't really expect the 18-hour "Goldilocks" P-Sol to work but had indications¹ that a 20-hour P-Sol was possible, our first test was a proof of concept with a 20-hour P-Sol representing a 16.7% shortened "day".

For the test tent, conditions were:

• 8 hours light / 12 hours dark (8/12): 20 hours total
• 50% increased light intensity relative to the control
• 56 P-Sols would be achieved in 47 calendar days (a 9-day reduction)

Observant growers are familiar with the daily leaf movements (nyctinasty) cannabis plants display: folding upward during the day ("praying") and downward as night approaches. After a few days on their new P-Sol schedule, the test plants displayed leaf movement consistent with their shortened P-Sol rather than a 24-hour day, indicating that their circadian rhythm was indeed being shortened.

The test plants seemed to initiate flowering before the control, but with 14 light/dark cycles being separated by only 2.3 days at that stage, it was not possible to say for certain. However, by calendar day 47, the test plants with a 20-hour P-Sol had amber trichomes, while none of the 24-hour control plants did. No stress or growth anomalies were noted; the test and control plants were of similar size and vigor.

So for our first 20-hour P-Sol test the results were:

• Plants synchronized with the shortened schedule
• Earlier ripening in line with the expected 56 P-Sols
• No observable stress
• Comparable vigor, yield and quality

The most annoying aspect of this test was that on some days the lights-on period for the test tent occurred entirely outside of normal working hours, so we couldn't check on the plants every day.

Having proven the concept, we decided to get more aggressive.

18-Hour Goldilocks P-Sol Test

We next tested the 18-hour "Goldilocks" P-Sol that we had identified as being ideal for scheduling, with a 25% reduced "day".

For the test tent, conditions were:

• 6 hours light / 12 hours dark (6/12): 18 hours total
• Doubled light intensity (a 100% increase) relative to the control
• 56 P-Sols would be achieved in 42 calendar days (a 14-day reduction)

As mentioned before, the Goldilocks P-Sol allows for a schedule where at least one hour of lights-on time falls between 9am and 5pm each day, making it easy to monitor the plants.

Every day we looked for signs of stress on the 18-hour plants, but never saw any. On the 42nd calendar day, when 56 18-hour P-Sols had passed, the test plants had some amber trichomes, with none on the control plants. At 42 calendar days, the test plants looked to have similar size, quantity and quality of flowers as the control plants did 14 days later.

Two full weeks had been successfully removed from an "8 week" flowering cycle.

To summarize the test results:

• Flowers ripening after 42 calendar days
• Comparable quality and yield
• No stress observed
• Equivalent flower development to control plants 14 days later

At this point we stopped asking if an 18-hour P-Sol was biologically possible. We started thinking about whether and how this could transform commercial cultivation.

Implications of Our Experimental Results

Our testing demonstrated that the P-Sol method can accelerate the flowering and ripening of photoperiod-sensitive cannabis by approximately 25%. It's possible that this could be pushed even farther to produce even greater acceleration.

There are still many unknowns, and certainly much more testing to do.

Different strains may behave differently under the accelerated schedule. From the Dodd et al. study¹ we infer that some cultivars are likely to perform better than others with a shorter P-Sol.

It could also be that the acceleration of ripening is not entirely linear with shortened P-Sols- for example, a strain that normally is ripe at 56 days may take 58 18-hour P-Sols to reach the same level of ripeness.

As temperature changes have also been shown to help reset circadian clocks, providing more extreme changes in temperature between the light and dark periods may help additionally accelerate plants' metabolism with the shortened P-Sols.

These are just a few of the many unanswered questions- there are myriad more things to ponder and test to optimize P-Sol growing.

Our experimental setup was designed to see if it was possible to "trick" the plants into accelerated maturation, but was not ideal to test if this methodology affects yield or cannabinoid and terpene production. We didn't even harvest the test flowers at the appropriate P-Sol as we wanted to observe their continued maturation.

To fairly test quality and yield, the test plants should be given ideal P-Sol aligned environmental controls, and fertilizer schedules based on their accelerated timeline. However, the quality and quantity of flowers from the test and control plants in our experiments were comparable- we saw no significant reduction in yield or quality.

Where are P-Sols Immediately Useful in Cannabis?

Until the P-Sol method can be proven viable for flower production at scale, there are immediate applications where this could make sense even if yield or quality are affected.

In "pheno hunting", you are only looking for the comparative quality of one plant versus another. Utilizing the P-Sol method to cut 25% off the time required to determine which phenotypes to keep and which to toss seems like an obvious win.

Breeding is another area where this method could be useful, especially if multiple generations of crossing are required. Getting stabilized seeds to market almost 25% faster is a clear advantage.

Beyond Cannabis

This isn't simply a Cannabis lighting strategy. Cannabis became our proof of concept because it is commercially valuable, well-understood, and commonly grown indoors in CEA. But cannabis is not the only nightlength-sensitive crop.

The P-Sol methodology is potentially an entirely different way of thinking about other photoperiod-sensitive crops. Not for mass-production of plants grown outdoors, but shortened photoperiods may eventually find applications in breeding programs, ornamental horticulture, seed production and other controlled-environment crops.

Interested in Experimenting With P-Sols?

Since there is much experimentation and exploration possible with the basic P-Sol concept, we want to encourage growers to try it themselves.

While using an interval timer to implement a non-24-hour P-Sol is relatively easy- at least for controlling lights- creating a calendar showing when lights are going to be on and off isn't trivial.

So we created a tool to allow you to create your own custom P-Sol schedule.

How This Could Change Commercial Cultivation

Obviously, more fine-tuned and large-scale tests should be performed before using the P-Sol method in commercial cannabis production. But the potential is clear: reducing harvest time by 25% would allow you to get more harvests per year.

However, even if we can make the plants mature 25% faster, it won't result in 25% more harvests or profits per year. There are many complications to consider when determining if moving to a shorter P-Sol would increase profit, and most are specific to each facility and market.

Workflow and Room Turns

For example, there is likely a fixed number of days it takes to harvest, clean and reset a flower room between runs. Shortened P-Sols can't make people work faster. Also, if you're harvesting more times per year, total labor costs associated with harvesting increase. There are many complications like these to consider when determining if moving to a shorter P-Sol would increase profit, and most are specific to each facility and market.

Electrical

A less-than 24-hour P-Sol coupled with a proportional increase in light intensity to maintain DLI (PLI) actually increases electrical use.

As a simple example, consider a flower room with 1000 watts in lighting: on a normal 12/12 schedule: this room would use 12 kilowatt-hours (kWh) of electricity each day. On a 6/12 Goldilocks P-Sol schedule, this room would need 2000 watts of lighting, but only running for 6 hours per P-Sol so would use the same 12 kWh per P-Sol.

However, since there is more than one P-Sol per day (33% more), on average the room would use 16 kWh of electricity each calendar day. This additional cost per-day is offset by the shorter number of calendar days for the run: the total electrical use and cost per flowering cycle doesn't change. But squeezing in more flower cycles per year requires more electricity per year.

HVAC

Increasing light intensity requires increasing HVAC capability and utilization. With the 6/12 Goldilocks P-Sol schedule, doubling of light intensity requires twice the lighting wattage and therefore twice the air conditioning capacity when the lights are on.

During lights-off periods, dehumidification is likely not affected, though it is possible that increasing the plants' metabolism does require additional dehumidification when lights are off.

And just as with lighting, even though maximum air conditioning wattage is only doubled, there is still a 33% increase in air conditioning kWh usage per day due to the 33% more 18-hour P-Sols in a 24-hour calendar day.

Capital Efficiency

Obviously, using shortened P-Sols to get more harvests from each square foot per year increases the effective utilization of building space, effectively reducing the cost of rent per flowering cycle, increasing operational profitability.

For many small and mid-size facilities, equipment such as trimming machines may be sitting idle much of the time between harvests. Harvesting more often increases the capital efficiency of these items as well.

Cash Flow and Annual Revenue

More frequent harvests would increase cash flow as long as yields are not too negatively affected. But given the issues touched on above and the variability between facilities, it can be complex to determine if moving to a shortened P-Sol could make financial sense.

So we adapted one of our standard commercial facility workflow planning models to examine the impact of shortened P-Sols on actual commercial production. This model allows setting different values for:

• The number of flowering days to harvest (if run as a "normal" 12/12 light/dark schedule)
• The number of days required to clean and reset a flower room
• Fixed costs per flower run such as materials and labor
• Average harvest weight per room per flower run
• Average sale price per pound
• Electricity cost
• Lighting and HVAC electrical usage (per hour with lights on for existing 12/12 rooms)
• Dehumidification and HVAC electrical usage (per hour with lights off)
• The length of a shortened P-Sol to model (with 12 hours of darkness to sustain flowering)
• Finally, a potential reduction in yield from running an 18-hour P-Sol.

Plugging in a wide range of values for these, we find that in most real-world situations converting to the 18-hour Goldilocks P-Sol would be more profitable per year even if the method reduces yield by 20% per harvest.

Sample output from our financial model showing potential benefits of switching to the 18-hour Goldilocks P-Sol.

You can play with this model to reflect your facility and test the limits.

ROI

Ultimately it all boils down to the return on investment (ROI). Since implementing shortened P-Sols in existing facilities likely requires purchasing more lighting and HVAC, it only makes sense if the increased annual profit pays off the initial investment in a reasonable amount of time.

This public model is necessarily a bit simplistic; every facility has unique constraints and issues. If you're interested in determining whether utilizing P-Sols in your facility makes financial sense, Black Dog HTC can model your operation and estimate the potential ROI before you change a single light.

Flipping the Script: P-Sols Longer than 24 Hours

We're aware of many facilities that have less-than-ideal lighting, whether from power restrictions, LED fixtures degrading due to inadequate cooling, or simply too few or meager light fixtures to start with. If cash for additional or replacement light fixtures is unavailable, the P-Sol method could be used with an illuminated period longer than 12 hours to increase DLI, and likely yield and quality along with it.

Many growers have experienced issues when their lights have stayed on longer than 12 hours, but that's likely because it came at the expense of the critical 12-hour dark period. Dr. Bruce Bugbee gives an excellent overview of how darkness (or the lack thereof) can delay cannabis flowering in a YouTube video.

Indeed, a February 2024 study by Ahrens, Llewellyn and Zheng² found that using a 13/11 schedule for flowering increased yield compared to a 12/12 control when given 540 μmol/m²/s PPFD- a light intensity level below what we normally recommend for flowering. This indicates that increasing the duration of light to increase DLI when starting with low PPFD can improve flower yields.

This study also noted that flowering initiation was 1.5 days slower in some cultivars with the 13/11 schedule, and inflorescence development was delayed in all cultivars tested, which we postulate could be the result of the decreased dark period.

With P-Sols, it's possible to provide the plant with a 13 hour day and a 12 hour night: more light, but matched with adequate rest.

This could increase yield without taking too much more time, and possibly reduce the slower flowering initiation and inflorescence development time seen in the studies.

For example a 13/12 lights on/off schedule would take 59 calendar days to cover 56 25-hour P-Sols. If flower initiation normally happens at day 14 when running a 12/12 schedule, and can be maintained at P-Sol 14 with a 13/12 schedule, flower initiation would only be 14 hours later than using an 13/11 schedule. For the 13/11 schedule in the study flowering initiation was delayed by 36 hours (1.5 days).

With a 13/12 25-hour P-Sol the flowering cycle would take ~5% longer to complete, but if the 35% yield increase and 9% increase in THC noted in the Ahrens et al. study were maintained, it would be an easy way to get higher yields and quality from existing equipment with minimal additional time.

From the Dodd et al. study¹ we infer that some cultivars are likely to perform better than others with a longer P-Sol. So for selected cultivars, the benefits could be even greater.

Most longer-than 24-hour P-Sols come with the downside of having days where the room would be lights-off for the entirety of some 9-to-5 workdays. A 13/12 schedule has stretches of 5 consecutive days with this issue. Moving to a 27-hour 15/12 schedule cuts this to only one day every 8 days, which might make it more palatable.

A 30-hour P-Sol (18/12) is the shortest longer-than 24-hour P-Sol where a room is lights-on for at least one hour each workday, but this also increases harvest time by 25%- an "8 week grow" would take 10 weeks.

We have not yet tested longer-than 24-hour P-Sols ourselves; it may be that increased yield does not justify the additional time. The research to date suggests it should work for light-challenged facilities.

Regardless, the idea is illustrative of the many directions this concept can be taken to benefit growers in specific situations.

Our modified workflow and revenue model allows for testing greater-than 24-hour P-Sols with 12 hours of darkness to examine potentially increased yields with a wide variety of variables; play with it yourself!

Sample output from our financial model showing potential benefits of switching to a 25-hour 13/12 P-Sol to take advantage of the 8.33% more light such a schedule would give the plants each P-Sol.

Just The Beginning of a Much Larger Conversation

The purpose of publishing this is not to claim that every commercial facility should immediately abandon conventional flowering schedules. Far from it.

Indeed, we've presented situations where both less-than and more-than 24-hour P-Sols could make sense. We know all too well that every facility is different with unique challenges- genetics, power availability, HVAC capacity, labor costs, workflow challenges, and market pricing. And implementing P-Sols isn't simply changing a timer.

Lighting intensity must change if moving to shorter P-Sols. HVAC and environmental control strategies must change. Electrical loading changes. Facility workflow would change, and economic modeling changes.

We've already spent years solving these problems. Our job isn't simply selling equipment, it's helping growers determine what makes economic and practical sense for their facility before they invest.

Depending on facility size, yields, market values and operating constraints, the financial impact could range from an additional harvest each year for smaller operations, to hundreds of thousands or potentially millions of dollars in additional annual production for larger commercial facilities.

We believe the P-Sol concept deserves rigorous validation and testing across genetics, cultivation methods, environmental conditions and commercial production systems.

For years we asked ourselves a simple question, believing it was likely too good to be true. After finally testing it, we believe the results and potential implications are too significant not to share.

For over 16 years Black Dog Horticulture Technologies & Consulting has been creating and delivering innovative products and solutions for the CEA industry. We're excited to share this concept with the community, and are certain that the highly-skilled and creative growers in the industry will find new ways to test, explore and expand this concept, possibly in ways we haven't even considered.

If future research continues to validate what we've observed, growers may eventually stop asking how to build larger facilities.

Instead, they'll ask how to make every existing facility efficiently produce more.

That's the future Black Dog HTC is and always has been working toward.

If you're interested in exploring how shortened or lengthened P-Sols, advanced lighting strategies, cutting-edge hydroponics, or facility optimization could improve your cultivation operation, we'd welcome the opportunity to discuss your goals. With decades of experience, we recognize and appreciate that every situation is unique.

Black Dog Horticulture Technologies & Consulting

www.BlackDogHTC.com

References:

1: Dodd AN, Salathia N, Hall A, Kévei E, Tóth R, Nagy F, Hibberd JM, Millar AJ, Webb AA. Plant circadian clocks increase photosynthesis, growth, survival, and competitive advantage. Science. 2005 Jul 22;309(5734):630-3. doi: 10.1126/science.1115581. PMID: 16040710.

2: Ahrens A, Llewellyn D, Zheng Y. Longer Photoperiod Substantially Increases Indoor-Grown Cannabis' Yield and Quality: A Study of Two High-THC Cultivars Grown under 12 h vs. 13 h Days. Plants (Basel). 2024 Feb 1;13(3):433. doi: 10.3390/plants13030433. PMID: 38337966; PMCID: PMC10857075.