By Adam Parsons Reviewed by: Miguel Ángel Garcia


Are you using guesswork when it comes to lighting your cannabis grow? If so, why not use a lux meter to gain more control? This device gives growers an approximation of the amount of light hitting their plants. It won’t tell you everything, but it’ll work better than your eyes alone!

Lux and PPFD: The Differences

Before we dive into the world of lux meters and their utility, it’s important to briefly touch upon an ongoing debate within the cannabis space. Though some cultivators claim to achieve consistent and solid results using a lux meter, these devices have their limitations.

You see, lux serves as a unit of measured brightness as perceived by the human eye. Our eyes are much more sensitive to yellow and green wavelengths of light, as opposed to blue and red. Lux proves useful when it comes to matters involving humans, but it doesn’t tell us much about the intensity of light useful for plants—i.e. the wavelengths that drive photosynthesis.

In contrast, photosynthetic photon flux density (PPFD) measures the amount of photosynthetically active radiation (PAR) light that hits a square metre each second. Therefore, PPFD can inform users about the concentration of useful light their plants are receiving. Measured in units of micromoles, the equation looks like this: μmol/m²/s. Compare this to lux, which only presents a reading related to illuminance based on human perception, and it’s clear that one has more utility within horticulture.

However, instruments used to measure PAR are considerably more expensive, and therefore less accessible to the home grower. While lux meters don’t reveal the density of photosynthetic light, they do come in handy when it comes to light placement—a variable that can make or break cannabis plant health and yield.

What Is a Lux Meter?

As the name suggests, a lux meter is a relatively simple device that measures lux—the unit of illuminance. More specifically, lux meters measure luminous flux per unit area. Luminous flux refers to the perceived power of light. When it comes to cultivating cannabis in a grow tent, the equation looks like this: lux = lumens/m².

Lux meters are a handy tool in a grower's arsenal, but they don’t offer the most appropriate assessment of light output. Whereas lux meters provide data on the intensity of light as seen by the human eye, PAR meters measure how many photons that drive photosynthesis are striking the leaf surface. Clearly, the latter has more of a function within a horticultural context. However, increased functions come with increased costs. Good PAR meters will start at around €230 and can reach over €2,000, whereas growers can get their hands on a rudimentary lux meter for as little as €20.

The Benefits of Using a Lux Meter

So, should you equip yourself with a lux meter? Are these devices a critical piece of kit alongside nutrients and lighting itself, or can you grow just fine without one? Discover the potential benefits of a lux meter below.

Helps to Increase Yield

If you know anything about growing plants, you’re aware of the importance of lighting. But growing good-quality cannabis indoors requires more than hanging up any old light and hoping for the best. Using a lux meter can help you position your grow light at the optimal distance above your canopy. Under ideal circumstances, growers can obtain exact information about correlation distance using a PAR meter or spectroradiometer. However, lux meters serve as the next best thing to achieve relative values according to the human perception of illuminance.

Step 1

Tells You When You Need to Replace HID Grow Lights

For a minor investment, a lux meter can save you a lot of time, effort, and disappointment. Eventually, certain types of grow lights, including MH and HPS, will lose efficacy. They’ll dip in performance, become increasingly dimmer, and fail to drive photosynthesis as effectively. Rather than sowing seeds and hoping your light has enough juice left in it, you can employ your lux meter before each grow to make sure you don’t run into issues in the coming weeks. Growers make all kinds of investments to ensure their grow runs smoothly. Why not grab a lux meter and make sure your lights are running well too?

Step 1

Prevents Some Plant Problems

Positioning your light source above your canopy is somewhat of a balancing act. Place it too close, and you run the risk of bleaching and light burn. Suspend it too far away, and you’ll miss out on vibrant, healthy growth. A lux meter will help you nail light positioning, resulting in healthier and more productive plants.

The Benefits of Using a Lux Meter

What Is the Optimal Amount of Light for Cannabis Plants?

Cannabis plants have different demands during different stages of the growing cycle; this applies to both nutrition and lighting. Seedlings can’t handle too much light, but too little will result in weak and leggy specimens. Slightly later down the line, during the vegetative phase, plants have a much higher demand for light—a fact made evident by their broad fan leaves. Cannabis also needs plenty of light during bloom to fuel the formation of flowers. However, budding plants thrive under a different spectrum of light than during veg.

How Much Light Do Your Cannabis Plants Require?

Roughly, the lux ranges below are best suited to their corresponding stage of the growing cycle:

Clone and seedling stage: 5,000–7,000 lux

How Much Light Do Your Cannabis Plants Require?

Vegetative stage: 15,000–50,000 lux

How Much Light Do Your Cannabis Plants Require?

Flowering stage: 45,000–65,000 lux

How Much Light Do Your Cannabis Plants Require?

Despite 65,000 representing the roof of recommended lux during the flowering stage, plants can handle up to 75,000 lux before things start to go south. With that said, illuminance values change a lot from one fixture to another; you should view these values as relative and not absolute.

Some growers approach cannabis with a “the more light, the better” mindset. This strategy only pays off until it reaches the 75,000 lux threshold. Light exposure of this magnitude can cause several issues. First, it can inflict light stress, which has the potential to reduce plant health and, subsequently, yield. This phenomenon manifests as dry, shrivelled leaves and bleaching. Second, this level of light intensity will drain your energy bill without actually doing much to increase plant productivity—you will reach a point of diminishing returns.

Lux for Cannabis: How to Measure the Amount of Light Your Plants Are Getting

Are you ready to master cannabis lux? Remember, using a lux meter will enable you to determine the luminous flux per unit area—illuminance—that your grow light provides at a certain distance. Using both a lux meter and the figures mentioned above, you can get closer to ensuring your plants receive adequate light exposure throughout the different stages of their life cycle. Follow these steps:

  • Take readings across your growing space: Set your light roughly 150cm above the floor of your growing space. Use your lux meter to get a reading directly under the light. From here, measure at different points around the growing space to determine any blind spots.
  • Rearrange accordingly: If you’re growing multiple plants, position them in areas that receive the most lux, and avoid areas that are lacking.
  • Adjust as you go: Your plant will grow noticeably, week by week. Use your lux meter to determine how much and often you should move your light by taking measurements around the canopy. Use the readings above to make sure you’re fulfilling the demands of the plant during particular stages of growth.

Lux for Weed Plants: A Note About LED

LED grow lights have become a go-to option for many growers, thanks to their reduced heat output and low running costs. However, certain types of LEDs can cause issues when it comes to gathering lux readings. Lux meters are able to give readings for all types of white lights, including HID, CFL, and some LEDs. They are not, however, compatible with purple LED lights. These models emit purple light due to a combination of blue and red diodes. Unfortunately, most cheap LED grow lights use this colour combination. If you’re using purple LEDs, you’ll have to rely on manufacturer information as an estimate of how much light the product emits. If you have the cash spare, you could purchase an alternative light meter compatible with purple-emitting LEDs.

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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: