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Cannabis cultivation: the artificial lighting minefield

In the second article of this three-part series, Dr Gary Yates, chief scientific officer at PharmaSeeds, discusses the use of artificial lighting for cannabis cultivation. 



Cannabis cultivation: the artificial lighting minefield
Home » News » Production » Cannabis cultivation: the artificial lighting minefield

Before the revival of Light-Emitting Diode (LED) technology, measuring and comparing lights for indoor cannabis cultivation was an easy and straightforward process. 

Like most of the horticultural industry, cultivators typically used High-Pressure Sodium (HPS) or Metal Halide (MH). Light intensity was measured by energy output generally for flowering, ranging from around 400 watts for modest setups all the way up to 1000+ watts for the more serious cultivators. 

In those days of old, the increase in light intensity generally came at a cost of both higher energy consumption and elevating temperatures – two things best avoided – and if the budget allowed for it, the higher-output HPS lights were used with appropriate climatic control measures for maximum gains. 

Read part one of this series: The additional lighting paradox

The era could be looked upon almost nostalgically as a simpler time, especially as, since the emergence of LED cultivation lights, choosing the optimal light; type, manufacturer and settings has become an anxiety-inducing nightmare due to the overwhelming number of companies claiming to have the best lights in the world. 

Slightly tweaking the light spectrum, reducing energy consumption, reconfiguring layout and position, use of different housing material, on/off ramping, flexible racking, weight of units and more are all considerations that have become part of the headache of choosing the optimal lighting system. One could be forgiven for feeling overwhelmed.

As if to muddy the waters further, there is a lack of standardisation in how manufacturers gauge the productivity of their lights. PPF, PPFD, umol/m2-1/s-1, Lux, PAR, Watts, Lumens, Candela, and Footcandle are some of the terms found when trolling the net for a suitable light manufacturer (OK I put Footcandle in there for fun, but all others are real examples). 

Read more from PharmaSeeds: Do we still need master growers now that there’s more research on cannabis?

Some of these units measure energy, some measure brightness, or flow of photons in set areas whilst others measure total flow. Having worked in a lab where the light intensity levels were crucial to the experiments, it is vital to have a standard universal method of measuring light intensity – especially with so many other variables involved in cultivation. This issue is further compounded by the fact that light spectrum plays a huge role in determining the output of plants.

As for the price comparison, HPS and MH lights are generally a good bit cheaper than LED – however, that statement is only true of the initial purchase since running costs of both are very different, with LED being the most favourable. 

In terms of outright purchasing cost, cultivation lights have a similar story to a cup of coffee from a café. In the mid-1990’s a cup of coffee in a UK café was usually somewhere between 20p to 50p, and the choice was one size, with sugar and/or milk – which you most likely added yourself. Now the cost of a cup of coffee has spiralled beyond 10 times that, and the options available between cup size, milk type, coffee type, drink style, syrups and toppings etc would allow one to essentially try a different coffee drink each day for the best part of a year.

Read more from Pharmaseeds: How much CO2 do your cannabis plants need?

This is every bit like the cultivation lights industry, where costs, choice and options have all spiralled to a point there’s possibly too much to choose from. Any meaningful comparison could only realistically compare 5-10 systems/different light manufacturers before controlling the other variables becomes unmanageable – not to mention space requirements and repetition numbers to validate the data. Therefore, it leaves a hole in the knowledge, adding more mystery to an industry already shrouded in misinformation and ‘bro-science’ and ultimately, an industry that lacks proper clarity at times.

In fact, proper comparisons between HPS and LED have also been sorely lacking in the peer-reviewed literature. There are still, from time to time, cultivators insisting on using HPS simply because it has proven effective in the past – but is this a good reason to continue? 

In a study set up to compare the different systems, Michel Jenkins and Curtis Livesay show some interesting data in their publication ’Photosynthetic Performance and Potency of Cannabis sativa L grown under LED and HPS Illumination’. In this study, which the authors claim to be a first of its kind, they start by comparing the consistency of light intensity within the area of coverage claimed by the manufacturers. 

Of the LED light systems tested, not only was there a larger variation than expected, but only one of the three manufacturers showed consistency close to what they claimed. The authors go on to show different metrics such as affect on leaf temperature and light response curves, but the most interesting claim was that LED light when averaged over 11 different cultivars produced ~5 per cent more THCA than the equivalent grown under HPS. Showing that HPS produced an average of 20 per cent THCA (+/- 3 per cent) over the 11 cultivars and LED produced 25 per cent (+/- 2.5 per cent), the authors failed to provide further breakdown of the data. 

In addition, the study was straightforward and the selected experiments make sense, but there is some unsubstantiated claims in the introduction, and no access to the supplemental data where they break down the comparison of individual cultivars grown under both lighting systems. This data would help explain how cultivars react to the different lighting systems as a function of the genotype – it may reveal that some cultivars are more susceptible to the different lights versus others. However, showing the +/- reduction (range of results) using LED points towards higher consistency at least.


When considering a lighting system, it would be wise to consider the supplier, their reputation, and how their previous customers review and rate the system, as testimonials and third-party validation are a useful proponent of the decision-making process. 

LED lighting for cultivation has become a minefield and it is so easy to get confused by all the options out there. Not understating the importance of competition in the marketplace to help drive prices down, make bespoke designs and keep driving innovation, but it would be so much handier if all these manufacturers used at least the same units of measurement and provided a comparison to a standard HPS. In addition, a standard ‘model’ cultivar would also increase reproducibility. 

This is a bit of a pipedream and unlikely to happen anytime soon, but as the industry continues to expand worldwide, cultivators and financers should surely be able to demand better standardisation and higher quality of researched data. It’s high time for an industry standard.

Gary Yates
Chief scientific officer


Discover Europe’s first registered cannabis seedbank

The bank is home to the seeds of 286 strains, including 19 Cannabis Cup winners.



Discover Europe’s first registered cannabis seedbank
Home » News » Production » Cannabis cultivation: the artificial lighting minefield

Europe now has its first ever legal and registered cannabis seedbank in Copenhagen, Denmark.

As countries across Europe begin adopting more open attitudes towards cannabis, the continent now has its first ever legal seed bank for the plant.

Franchise Global Health has confirmed that its Danish subsidiary, Rangers Pharmaceutical has successfully established the bank which it says is “arguably the largest in the world” with an audited value of more than C$9m (~€8.64m).

The seedbank houses more than 286 strains, including several world-class genetics and the winners of 19 Cannabis Cups.

Read more: Exploring cannabis yield optimisation with PharmaSeeds

Franchise Global executive chairman and CEO, Clifford Starke, commented: “Our goal is to become Europe’s most trusted source of high-quality EU-GMP cannabis. 

“This will be achieved in part by establishing our seedbank as a source for high-quality, Cannabis-Cup winning genetics. 

“Essentially this is 30 years worth of IP from land races all around the world with strong genetic heritage including from Thailand, Colombia and other highly sought after sources of origin.”

The company has stated the bank, which is licensed to store, sell and export cannabis seeds globally under legal international trade frameworks and import and export permits, is a key component to its IP strategy.

Read more: Germplasm selection – from seed culture to tissue culture

Franchise Global is offering a number of strains to the market and has subsequently signed numerous seed purchase orders and strategic agreements with emerging cannabis cultivators and wholesalers. The aim is to further expand global commercialisation opportunities and the orders will be fulfilled in the coming quarters, creating a new source of revenue for the Company and solidifying new global strategic alliances. 

However, Franchise Global will retain its most distinguished strains for its own internal flower production for global markets.

The company has strategically position itself in Germany which it says will act as a key gateway to Europe and beyond as its aims to provide international markets with high-quality medical cannabis products. It has a network of over 1,200 pharmacies in Europe as well as extensive distribution relationships across 18 countries.

To bolster its position in the country, the company has also announced it will acquire German pharmaceutical and medical cannabis products distributor.

Starke commented: “This acquisition will strengthen our position in Germany. The Target Company has significant experience with regulatory requirements, pharmaceuticals and medicinal cannabis.

“We expect it to be a solid addition to Franchise Global’s core position in Germany, providing deeper access to further pharmacies, wholesale distribution channels and advancing our business plan as Germany moves closer to full legalisation of recreational cannabis.

“We are focused on leading the pack in the medical cannabis market in Germany. By merging Franchise Global’s experience with the Target Company’s market presence, we are well on our way to be one of the premier German pharmaceutical and medical cannabis companies.”

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Cannabis cultivation: the additional lighting paradox

In the first of this three-part series, Dr Gary Yates, chief scientific officer at PharmaSeeds, discusses the use of lighting for improving cannabis yield. 



Cannabis cultivation: the additional lighting paradox
Home » News » Production » Cannabis cultivation: the artificial lighting minefield

In order to make gains on their yields, some Licensed Producers (LP) introduce supplemental lighting to their cultivation area. The need for this strategy is generally determined by certain variables, including the type of system, manpower available, and the size of the cultivation area.

Not everyone utilises this method, and whether a LP does or not is often a function of choice, experience and the type of genetics used. 

Before we break down the subject further, it is worth briefly explaining the three different types of light ‘additives’ discussed in this article (the source and quality of lights is not discussed here and is better reserved for an article where this is the primary focus).

Read more from Pharmaseeds:

Side Lights

Often vertically positioned, side lights can be added to increase secondary and tertiary (undergrowth) flower yield by increasing the light availability to the non-apical flowers.

Sub-canopy lights

These are lights positioned at the base of the plant to increase light availability to the lower parts of the plant (similar to side lights in terms of the goal they try to achieve)

Supplemental lights

Can be extra lights, e.g. in a Greenhouse to manipulate day length, but can also be included to simply add more photons to the growing area, again usually for the purposes of yield enhancement.

Lighting for yield

Training your plants, and increasing the number of apical buds by topping etc, has been shown to increase the yield capabilities, thus helping with the production of a consistent crop – although it should be noted that in some scenarios, this is not possible due to manpower, spacing issues and other factors. 

Read more from Pharmaseeds: Do we still need master growers now that there’s more research on cannabis?

Many auto-flowering cultivars lose the capacity to automatically flower independent of day length when they are cut. In this scenario, adding illumination to the lower parts of the plant may be beneficial to the overall yield of the plant.

In a 2018 study by Hawley et al, the addition of sub-canopy lights was tested in controlled experiments using RGB (Red Green Blue) LEDs or RB (Red Blue) LEDs. The authors claim that yield is enhanced by up to 19 per cent to 24 per cent as a function of the increased light intensity reaching the mid and lower canopy (normally shaded by the top of the plant), however, the study did not address the quality of the flowers produced on the lower canopy. 

They also flowered at a surprisingly low temperature, although the study did not mention how the upward facing lights can adversely affect the plants. Plants detect the direction of light, and it is not out-with reason that illumination from directly underneath may cause conflicting signalling cues. Most photosynthetic parts of a plant are positively phototropic, therefore when the light sources are in opposite directions, they will try to face the strongest light source (even a single leaf can be pulled in two different directions), but such movement comes at a high energy cost to the plant. 

Despite this potential negative outcome, the authors show that as well as yield, bud-to-leaf ratio is increased with sub-canopy lighting. Furthermore, minor changes in terpenes (but not cannabinoids) take place.

Read more from Pharmaseeds: How much CO2 do your cannabis plants need?

It is worth mentioning that photosynthesis in plants can be limited by the following: Intensity/quality of light, and CO2/Water/Nutrient availability. The saturation limit for photosynthesis is typically around 1800 μmol·m-2·s-1 – however, using only static lights from above means that once the top canopy is maximised for light intensity, the lower parts of the plants receive less intense levels of light due to shading. 

Should you increase the overhead light intensity only, in order to penetrate deeper into the plants, there is a risk of inducing high light stress responses, causing photodamage.


Improving yield in the lower parts of the plant may be achieved by increasing intensity of light to the mid and lower tiers, toward the 1800 μmol·m-2·s-1 saturation limit – but avoid increasing overhead light intensity. 

This can be achieved by using side or supplemental lights, carefully positioned, and utilising upward-facing sub canopy lighting. Upward-facing sub-canopy lighting should be an alternative only if side-facing lights are not viable, although additional research is necessary to clarify if direction is a limiting factor.

As with any adjustments to the growing environment, small, incremental changes are easier to manage, and if possible, always run a trial before introducing on a large scale.

Gary Yates
Chief scientific officer

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White paper explores the sustainability of cannabinoid production

Cellular Goods explores biotechnology and synthetic chemistry for sustainable production.



White paper explores the sustainability of cannabinoid production
Home » News » Production » Cannabis cultivation: the artificial lighting minefield

With a rising demand for cannabinoid products, there will be a vital need for sustainable methods of production as the industry matures.

A new white paper from Cellular Goods explores improved sustainability and increased purity of lab-based production of cannabinoids when compared with traditional agricultural production.

According to Vantage Market Research, the global market CBD market is expected to grow from US$4.9bn (~£3.90bn) in 2021 to $47.22bn by 2028. 

As products such as supplements and cosmetics containing cannabinoids become increasingly popular and countries across the globe loosen regulations on cannabinoids, different methods of production will need to be leveraged to keep up with demand and avoid production bottlenecks.

Read more: PharmaSeeds discusses improving cannabis yield

The global demand for cannabinoids has been primarily driven by sales of CBD, which so far has been satisfied by agricultural cultivation of the plant from which cannabinoids are extracted – an inefficient process.

The paper states: “There is a significant need for sustainable bulk-chemical production, including the popularised cannabinoids, particularly given the cultural pressures of rising consumer awareness, product sustainability, climate change and environmental stewardship.”

Synthetic production

The paper highlights that cannabinoids make up just 2 to 5 per cent of the plant by mass, leading to approximately 90 per cent of the plant ending up as botanical waste. Agricultural production also uses large amounts of land and water, has yield variability, as well as having potential microbial and chemical contamination and crop loss.

The paper states: “Until recently, access to cannabinoids has been restricted to the cultivation of Cannabis sativa and extraction therefrom, a labour and energy intensive process; and akin to other crop productions systems the limitations are being realised as cannabinoid demand is commercialised. 

Read more: Cannabis and climate change environmental impacts

“High yield variability, microbial and chemical contamination and crop-loss are all issues that plague Cannabis sativa. Furthermore, this type of agriculture has a negative environmental impact as it uses large amounts of land, water, fertilizers and pesticides, and has a high carbon footprint (electrical usage).”

Highlighting that the production capabilities of cannabis have shown diminishing economic returns, in particular for extracting and producing minor cannabinoids, the paper states that biotechnology and synthetic chemistry have provided the tools and processes necessary to produce at a commercial scale with significantly fewer environmental drawbacks and waste. 

Synthetic production methods are utilised for a variety of everyday products such as flavouring extracts, replacement hormones, antibiotics, pigments and terpenes, for example, where compounds are created that are identical to their natural counterpart. 

The paper highlights that the evolution of biosynthetic production techniques has also provided the ability to make changes in the genetic material of organisms and that computational power has provided further insights into the potential for modifications of biological systems. 

It demonstrates that biotechnology and synthetic chemistry allow cannabinoids to be produced at a commercial scale with increased purity, upwards of 95 per cent.

It shows that, to produce 1,000kg of cannabigerol (CBG) outdoor production requires 208 per cent more time, and requires 40 acres of land, where as lab-based production requires less than one acre. 

Read more: New technology maximises cannabis yield and reduces waste

In outdoor CBD production, CO2 emissions are 44 times higher than by biosynthesis and requires 333 times more water. For biomass waste, biosynthesis produces 99.93 per cent less waste than agricultural production.

Cellular Goods CEO, Anna Chokina, commented: “The publication of today’s white paper illustrates our continued commitment to creating environmentally conscious, efficacy-led products.  

“Cellular Goods exclusively uses lab-produced cannabinoids in its products, and this decision is fully vindicated by this white paper.

“Not only is the production process more sustainable, requiring less land, water and producing greatly decreased biomass waste and carbon emissions than agricultural production, but lab production gives the opportunity to increase production without suffering systemic and biological restraints. 

“Use of lab production provides a greater ability to respond to any increases in demand in the cannabinoid space, as consumers become increasingly conscious of the effective skincare and wellness applications of  cannabinoids.”

Istok Nahtigal, Head of Process and Applied Sciences, commented: “Our research has further evidenced Cellular Goods’ existing belief that lab-production methods for producing cannabinoids are the future.

As consumers become increasingly environmentally conscious, it is important to prioritise ecological methods of production. Lab-production is a win-win for the company, as it is not only more  sustainable, but produces purer, higher quality products.”

To read the full white paper please visit:

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