By Max Sargent


  • PGRs are naturally occurring and synthetically produced compounds that affect plant growth.
  • They can increase marijuana yield but reduce terpene and cannabinoid production.
  • Synthetic PGRs can be very damaging to the environment.
  • Their application in food crops is associated with various health problems.

Plant growth regulators (PGRs) are chemical inputs used to improve bud size and yield. They essentially work by hacking plant hormones to accelerate processes that fuel growth, and suppress ones that deter or diminish it. However, these molecules are also known to damage the environment and might pose a threat to human health. Learn more about these controversial growth regulators, and how to identify PGR weed.

Side-by-side cannabis buds: Dense, brown 'Cannabis with PGRs' vs. greener, fluffier 'Cannabis without PGRs.' Learn to spot the difference!

What Are PGRs in Weed?

PGRs are simple molecules that—you guessed it—aim to regulate plant growth and development. Several of these chemicals occur naturally in plants, where they help to drive important physiological processes. However, humans have successfully engineered synthetic PGRs that are applied to increase harvests and extend the postharvest life and storage quality of fruits.

Naturally, commercial cannabis cultivators have developed an interest in these chemicals. They work well on other fruit-bearing crops, so it stands to reason that PGRs could help to bolster bud size, increase harvest weight, and ultimately improve profit margins. But are they good for consumers?

Although PGRs help to maximize volume, consumers are showing increased demand for organic, sustainable, and artisan marijuana products free from synthetic inputs and grown on a smaller scale. The presence of any contaminants doesn’t sit well with many cannabis users.

But aren’t PGRs applied to food crops? They are indeed. For example, farmers apply various kinds of these chemicals to improve the shapes of apples and to stop fruits from dropping too early. But many commercially grown foods also contain pesticide residues—just because an agriculture input enhances growth and productivity doesn’t mean it's safe to ingest.

Below, you’ll get to know PGRs on a deeper level. After finding out how they work in plants, you’ll discover if they pose any danger, as well as how to identify weed grown with PGRs.

The Role of PGRs in Plants

PGRs are essential for plant growth, and thus are also essential for the growth of cannabis plants. They are plant hormones, and just like animal hormones help to regulate physiological events, plant hormones drive growth, flowering, fruiting, and other essential processes.

However, in animals, hormones enter systemic circulation to exert effects via distant organs and glands. In plants, hormones tend to produce effects right where they’re synthesized. Thus, these chemicals work to exert isolated effects—but they also work together to produce a range of responses.

Abscisic acid
This PGR works to close stomata (the small pores on the surface of leaves) during drought conditions. Because these holes regulate the movement of gases in and out of leaves, closing them allows plants to hold on to water when the resource becomes scarce. Abscisic acid also plays a role in abscission—the natural detachment of dead leaves and fruits from branches.
Ethylene
This plant hormone contributes to the senescence of leaves and flowers. Have you ever picked a tomato and watched it turn red on the windowsill? You can thank ethylene for facilitating the ripening process off the branch.
Gibberellin
This chemical plays a key role in germination. As germination begins, enzymes free up gibberellin into its active form. The chemical then breaks the seed’s dormancy. The molecule also regulates sexual expression and plays a role in hermaphroditism in numerous species.
Auxin
This PGR plays several crucial roles, including the formation of root cells. Auxin also underpins phototropism—the process that causes plants to grow toward light.
Cytokinin
These chemicals help to drive cell division and fight off senescence.

Why Do Growers Use PGRs on Marijuana?

Ultimately, cultivators apply PGRs to cannabis to produce bigger and thicker buds. For commercial growers, this has obvious benefits, but for consumers, there are significant drawbacks. Although PGR weed may be visually and economically appealing, these aesthetics come at a cost.

Applying PGRs to plants essentially hacks their endogenous hormones. Naturally occurring hormones work partly by breaking down or activating DNA transcription proteins. These proteins either activate or suppress genes that promote growth, and hormones maintain control over them.

The introduction of synthetic exogenous hormones allows growers to disrupt this biological process. By adding hormones that activate transcription proteins, growers can intentionally ramp up the number of proteins that promote growth, and suppress those that slam on the brakes.

This tinkering leads to larger and thicker buds that look much more appealing to the naked eye. The activation of growth-promoting genes causes cells to uptake more water, which forces them to expand. Auxin also plays a role in increasing the size of plant cell walls.

However, despite bigger buds, playing around with plant hormones comes with a serious downside for cannabis growers; compared to normal flowers, PGR weed features lower levels of cannabinoids and terpenes. As such, these buds are much less tasty than those that don’t undergo treatment, and produce less pronounced psychoactive effects.

The reasons for this are complex. First, the amplified growth causes the redistribution of resources away from the production of terpene and cannabinoids and towards the growth of new cell walls.

Further, as PGRs suppress the production of certain stress-related hormones, the plants develop smaller trichomes, as these are essentially defense mechanisms that develop under stress.

Finally, some synthetic PGRs, especially non-organic ones like paclobutrazol or daminozide, can inhibit key enzymes in the biosynthetic pathways of terpenes and cannabinoids. This can lead to a direct reduction in the plant's ability to produce these compounds.

For these reasons, and ethical considerations around harm to the wider environment and end user, growers should be very careful before applying synthetic PGRs to their crop, and consumers should shy away from PGR-treated cannabis.

Worker spraying cannabis plants in an outdoor grow operation, applying nutrients or PGRs with protective gear.

Are PGRs Dangerous?

Ongoing studies are exploring the potential impact of PGRs on human health. While PGRs are approved for agricultural use in some countries, they are banned in others. For example, European farmers are able to use daminozide as a pesticide, but it’s deemed a probable carcinogen in the United States and remains illegal to apply to crops.

Check out some of the most common synthetic PGRs below, and their potential dangers:

  • Chlormequat chloride: This small and simple molecule helps to bolster yield in grains, tomatoes, and peppers, among other plants. However, exposure to the chemical can irritate the lungs and cause nausea in the short term, and can damage the liver[1] over long periods of exposure. Additionally, studies suggest that chlormequat chloride may affect hormone levels in mammals, raising concerns about its long-term safety.
  • Daminozide: Approved for use in a host of European countries, this PGR is used to enhance the growth of tree fruits such as peaches, cherries, prunes, and pears. Despite its efficacy, the Pesticide Properties DataBase, published by the University of Hertfordshire, lists daminozide as a probable human carcinogen[2]. When burned, as might happen with marijuana consumption, daminozide can form nitrosamines—highly toxic and carcinogenic compounds.
  • Paclobutrazol: This chemical works as a plant growth suppressor by inhibiting the natural PGR gibberellin. It helps to reduce internodal spacing and create stouter plants that fruit earlier. However, the molecule has been shown to produce reproductive and developmental issues[3] in animal models. Furthermore, studies indicate that paclobutrazol can remain in soil for extended periods, potentially affecting subsequent crops and nearby vegetation.
  • How PGRs Impact the Environment

PGRs are also known to be damaging to the wider environment, making their use dangerous not only for those who directly consume them, but for everything and everyone.

PGRs have damaging effects on a range of different systems:

  • Aquatic ecosystems: Runoff from agricultural fields containing PGRs can make its way into rivers, streams, and other water bodies. Research has shown that PGRs can affect aquatic species. For example, they can disrupt the endocrine systems of fish, impacting organ development and reproductive capacity. Some chemicals, such as paclobutrazol, have been shown to bioaccumulate, meaning they persist in the food chain and pose long-term ecological risks.
  • Soil degradation: Repeated application of synthetic PGRs can lead to the buildup of chemical residues in soil. Over time, this can alter microbial communities that are essential for healthy soil function, potentially reducing fertility and the ability of the soil to sequester carbon. In some cases, these residues may inhibit the growth of non-target plant species, reducing biodiversity in agricultural and natural ecosystems.
  • Broader environmental risks: Poor soil practices, such as excessive tilling and lack of erosion control, exacerbate the problem by increasing runoff and allowing these chemicals to enter groundwater systems. This contamination can lead to a range of downstream effects, including the disruption of aquatic ecosystems and the pollution of drinking water sources.
  • Regional Regulatory Differences

The regulation of PGRs varies widely across the globe, reflecting differences in scientific assessment, public health priorities, and agricultural needs.

  • United States: Regulatory agencies like the Environmental Protection Agency (EPA) have banned certain PGRs, such as daminozide, due to their carcinogenic potential. This has led to stricter standards for crops like cannabis, which are often consumed directly.
  • European Union: While some PGRs remain in use, regulatory bodies like the European Food Safety Authority (EFSA) continuously evaluate their safety and environmental impact. Daminozide, for instance, is permitted but under strict conditions.
  • Asia: In countries like China and India, PGRs are widely used to meet high agricultural demand. However, regulatory oversight may be less stringent, leading to potential overuse and environmental contamination.

How to Identify PGR Weed

You can find PGR weed basically anywhere, especially in countries where cannabis is illegal and unregulated. But how can you tell these contaminated buds apart from untreated ones? Luckily, there are several telltale signs; but before we proceed, you should know that not all PGRs are toxic.

Some natural PGRs, such as kelp and chitosan, create buds that look similar to synthetically treated ones, without adding a toxic burden. Therefore, you need to consider your source and how much you trust them when you come across buds with these traits.

A guide on how to identify PGR Weed, listing key characteristics, with the RQS logo in the bottom right corner.
  • Step-by-Step Guide to Identifying PGR Weed

  1. Dense, rock-hard buds: PGR weed is extremely dense. Although some growers brag about how dense their flowers are, PGR buds look unnaturally thick. They feel heavier in the hand, and they’re slightly harder to break apart with the fingers. Weed that looks unusually thick ends up this way due to unnatural hormone hacking.
  2. Lack of trichomes: PGR weed has much less of a sheen compared to natural cannabis due to reduced trichome count. These sparkly glands produce cannabinoids and terpenes, so their absence results in lower potency and aroma.
  3. Unusual texture: PGR-treated buds often have a spongy or damp texture. Natural buds are firm but slightly sticky, while PGR weed can feel unnatural to the touch.
  4. Absence of strong aroma: PGRs may create thick and large flowers, but they negatively affect the terpene profile. PGR-treated flowers are much less aromatic than their natural counterparts. Even when pressing them up against your nose, you’ll detect light scents of earthiness at best.
  5. Bright orange pistils: PGR weed often features excessive and unnaturally bright orange pistils (the hair-like structures on buds). While pistils occur naturally, the exaggerated coloration in PGR weed is a common sign of chemical interference.
  • Comparison with High-Quality Natural Cannabis

Need to detect PGR-treated weed at a moment's notice? Use the following as a reference for telling natural and PGR cannabis apart.

  • Natural cannabis has a balanced density, abundant trichomes, and a sticky but firm texture. Its aromas are rich, diverse, and strain-specific, with naturally colored pistils.
  • PGR cannabis appears unnaturally dense, lacks trichomes, and may feel spongy or wet. Aromas are faint, and pistils are excessively bright and orange.

PGRs: A Reason to Grow Your Own

There’s a whole lot of weed out there, and a big portion of it contains PGRs—but there’s a silver lining to this. These contaminants make weed users think twice before buying, ultimately pushing them toward growing organically at home or purchasing naturally cultivated buds from small businesses in legal markets.

Avoiding PGR weed is better for our long-term health, our immediate enjoyment of marijuana, and for the wider environment. The more we educate ourselves about the potential dangers of the cannabis supply chain, the more we can strive to make better decisions.

Disclaimer:
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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Privacy Policy - Royal Queen Seeds

To ensure a safe online environment and guarantee adequate data protection, we strictly comply with all legal requirements. In this privacy statement, we provide information about how and for what purpose data is collected, safety measures, storage periods and contact details.


COMPANY NAME: SNORKEL SPAIN, SL (hereinafter ROYAL QUEEN SEEDS)

C/ Vilar d'Abdelà, 5 (nave 1) CP: 08170 de Montornès del Vallès

+34 937 379 846

support@royalqueenseeds.com


The present Privacy Policy sets out the terms on which we will treat personal data at ROYAL QUEEN SEEDS; this includes any personal data collected through our website https://www.royalqueenseeds.com/ as well as any other data we process in the course of our business activities.

ROYAL QUEEN SEEDS collects the following personal data for the purposes listed below:

SECTION 1 – PERSONAL INFORMATION WE COLLECT

1.1 Account purchases

Account purchases can only be made if you are in possession of a personal account. When you create an account or purchase something from our shop, as part of the buying and selling process we collect the following personal information that you provide to us:

This information is required for delivery. In addition, when you browse our shop, we automatically receive the Internet Protocol (IP) address of your computer. Based on this information, we can optimise your online experience and at the same time protect our online environment.

Purpose of data collection

We collect and store account-related data for the following purposes:

(a) to carry out obligations arising from any contracts between you and us, and to provide you with information, products and services that you may request from us;

(b) to set up, manage and communicate with you about your account and your orders;

(c) to conduct market research and analysis;

(d) to confirm your age and identity, and to detect and prevent fraud.

1.2 Newsletters

With your explicit permission, we may send you newsletters about our shop, new products and other updates. We send newsletters based on your explicit consent. In the event that you purchase a product, and in accordance with current regulations, we may send you commercial communications in accordance with the legitimate interest of our company, always about products or services similar to those you have purchased or contracted. In any case, you may exercise your right of opposition through the channels announced in this Privacy Policy. The following information is collected in relation to the newsletter:

We do not need to know the sex of the person in order to send the newsletter (data minimisation: by law we must ask for data that is strictly necessary to provide the service, and in this case knowing the sex is not necessary to send the newsletter).

Purpose of data collection

The data collected is used to:

(a) personalise our emails, including your name and gender;

(b) provide gender-specific content.

You can withdraw your consent at any time by using the link provided in the newsletter or the contact information provided in section 2.

1.3 Customer service and contact form

In order to provide appropriate support, our customer service employees have access to information related to the account. Consequently, their support will be highly effective and friendly. The data provided in our contact form is used by our CRM provider, SuperOffice. We will only use your details to respond to your message.

SECTION 2 – LEGITIMATE INTEREST

If you have purchased any of our products, please note that we may process your personal data for promotional purposes, based on Royal Queen Seeds' legitimate interest only to offer you products or services from our company and about products or services similar to those you have purchased. You may exercise your right to opt out of future messages by the means set out in this Privacy Policy or through any notification you receive.

2.1 How do you withdraw consent?

If you change your mind, you can withdraw your consent for us to contact you for the purpose of collecting, using, or disclosing your data at any time by reaching out to us at: support@royalqueenseeds.com.

SECTION 3 – DISCLOSURE

We may disclose your personal information if we are required to do so by law or if you breach our Terms of Service.

SECTION 4 – HOW LONG DO WE KEEP YOUR DATA?

At Royal Queen Seeds, we will not retain your data for longer than is necessary for the purposes described in this Policy. Different retention periods apply for different types of data; however, the longest period we will normally hold any personal data is 10 years.

4.1 Account information

Data relating to the account remains relevant for as long as the consumer is in possession of an account. Therefore, the data remains documented for as long as the account exists. When our customers delete an account, the associated data will be deleted within a reasonable period of time. Requests regarding the inspection or correction of stored personal data or the deletion of an account can be sent to support@royalqueenseeds.com.

4.2 Newsletters

In the event that you give us your consent to inform you about our products or services, we will keep your data until you express your wish not to receive any further communications from us. However, we regularly (every month) carry out a relevance check. Registered customers (and their personal information) will be deleted whenever customers do not reply to our request. In addition, our newsletter mailing has an opt-out feature. Consumers can withdraw their consent by using this opt-out feature.

SECTION 5 – COOKIES

Cookies are small information files that notify your computer of previous interactions with our website. These cookies are stored on your hard drive, not on our website. Essentially, when you use our website, your computer displays its cookies to us, informing our site that you have visited before. This allows our website to function more quickly and remember aspects related to your previous visits (such as your username), making your experience more convenient. At Royal Queen Seeds, we use two types of cookies: functional and analytical.

5.1 Functional Cookies

Functional cookies are used to enhance your online experience. Among other things, these cookies track what is added to your shopping cart. The use of these cookies does not require prior authorization.

5.2 Analytical Cookies

Analytical cookies are used for research and market analysis. The data collected with these analytical cookies is anonymous, making it unusable for third parties. The use of these cookies does not require prior authorization.

SECTION 5 – THIRD-PARTY SERVICES

Third-party services are required to conduct transactions and provide our services. In general, the third-party providers we use will only collect, use and disclose your information to the extent necessary to enable them to perform the services they provide to us.

However, certain third-party service providers, such as payment gateways and other payment transaction processors, have their own privacy policies regarding the information we must provide to them for your transactions.

We encourage you to read the privacy policies of these providers so that you can understand how these providers will handle your personal information.

In particular, certain suppliers may be located or have facilities located in a different jurisdiction than yours or ours. Therefore, if you choose to proceed with a transaction involving the services of a third party, your information may be subject to the laws of the jurisdiction in which that service provider or its facilities are located.

Once you leave our website or are redirected to a third-party website or application, you are no longer governed by this Privacy Policy or the Terms of Service of our website.

Web analytics service (anonymous data)

On this website we have integrated an element of a web analytics service (with anonymisation functionality). Web analytics can be defined as the gathering, processing and analysis of data about the behaviour of visitors to websites. An analytics service collects, among other things, data about which website a person came from (the so-called referrer), which sub-pages they visited or how often and for how long they visited a sub-page. Web analytics is mainly used for website optimisation and for a cost–benefit analysis of internet advertising.

Courier service

To complete deliveries we use a courier service. This courier service carries out the delivery between our company and the consumer's home. To complete these logistics, the company requires access to the consumer's name and address information.

Mailing service

Royal Queen Seeds uses a third-party mail service provider to send its newsletter. This provider has access to limited account information related to opt-in consent (e.g. email address).

Marketing services

Royal Queen Seeds has the support of a company that specialises in marketing and communication activities. Their access to personal information is very limited and mostly anonymous.

Payment services

At Royal Queen Seeds we use external payment services to handle our transactions (e.g. credit card payments).

SECTION 6 – SECURITY

To protect your personal information, we take reasonable precautions and follow industry standard best practices to ensure that it is not inappropriately lost, misused, accessed, disclosed, altered or destroyed.

If you provide us with your credit card information, the information is encrypted using secure socket layer technology (SSL) and stored using AES-256 encryption. Although no method of transmission over the internet or electronic storage is 100% secure, we follow all PCI-DSS requirements and implement additional industry standards that are commonly accepted. Information related to the account is protected with a hashing method. This method transforms the information into a generated hash. As a result, confidential information is protected and invisible, even to us. In addition, our databases are exceptionally protected against unauthorised access. For example, access to the database is only possible and permitted via approved IP addresses (e.g. from Royal Queen Seeds headquarters). Other attempts and addresses are rejected at all times.

Furthermore, data is anonymised as much as possible, so it cannot be directly linked to a specific consumer. With this data, however, we may be able to carry out market research and analysis. In addition, the third parties concerned (e.g. mailing service) are examined prior to our collaboration, comply with the GDPR from the EU and receive a processing agreement. Within Royal Queen Seeds, employees are assigned different access permissions. Specific permission provides access only to information that is strictly required to perform a task. Digital security measures are subject to change and must meet high requirements to ensure the safety of online customers. That is why, at Royal Queen Seeds, we appoint a security officer. Regular verification and improvement of security measures (where necessary) are part of the role.

SECTION 7 – CHANGES TO THIS PRIVACY POLICY

We reserve the right to modify this Privacy Policy at any time, so please check back regularly. Changes and clarifications will be effective immediately upon being published on the Website. If we make substantial changes to this policy, we will notify you here that it has been updated so you will know what information we collect, how we use it and under what circumstances, if any, we use and/or disclose it.

SECTION 8 – YOU HAVE THE RIGHT TO: