Cannabis Grow Guide by Royal Queen Seeds

By Steven Voser Reviewed by: Mr José

A full rundown on why and how to feed your cannabis plants.


All the nutrients needed for cannabis plant development are naturally present in the environment. However, to help your plants develop even faster and produce a better end product, you’ll want to feed them with fertiliser—concentrated nutrients.

Below, you’ll find all the information you need to know about when, how, and how much to feed your cannabis plants.

UNDERSTANDING CANNABIS MACRO AND MICRONUTRIENTS

Cannabis plants require three nutrients in large quantities. These macronutrients are nitrogen (N), phosphorus (P), and potassium (K), and they form the cornerstone of cannabis plant health. As such, these three nutrients usually feature front and centre on fertiliser products in the form of an NPK ratio. The higher the number for each value, the higher the concentration of that particular nutrient.

However, cannabis needs more than just three nutrients to survive and thrive. It also counts on secondary nutrients like calcium, magnesium, and sulfur to play vital roles in plant growth:

  • Calcium is important for cell wall development, can help reduce soil salinity, and improves water penetration when used as a soil amendment.
  • Magnesium plays a key role in photosynthesis and carbohydrate metabolism, and also helps with the stabilisation of plant cell walls.
  • Sulfur is necessary for the formation of chlorophyll and the production of proteins, amino acids, enzymes and vitamins, and protects plants against disease.

Beyond this, plants also make use of several other nutrients in small quantities (micronutrients) that are nevertheless extremely important. These include boron, chlorine, copper, iron, manganese, molybdenum, and zinc. While these aren’t the main nutrients plants use for food, they still play very important roles in various aspects of plant health.

Check out our video, 'How to Use Cannabis Nutrients,' for a visual guide on ensuring your plants get exactly what they need.

Video id: 207447257

NOT ALL CANNABIS FERTILISERS ARE MADE EQUAL

There are many different brands of cannabis nutrients on the market, and they can differ considerably.

Typically, cannabis fertilisers will vary in the four following areas:

  • Nutrient ratio: Different brands use different nutrient ratios they consider optimal.
  • Ingredients: Different fertiliser brands can achieve the same nutrient ratios using completely different ingredients, ranging from the most chemical (or “artificial”) to the most natural.
  • Soil or hydro: Soil nutrients are very different from hydro or soilless nutrient solutions. Make sure you only use fertilisers designed for your growing medium.
  • Supplements: Many fertiliser brands also make “supplements”. These products typically contain low NPK ratios and instead feature other nutrients designed to boost certain aspects of growth. Some supplements, for example, are essentially molasses.

In general, we recommend you focus more on meeting your plants' demands for macro and secondary nutrients before pumping them full of supplements. Going overboard with nutrients can result in chemical interactions or nutrient burn, which can significantly impact the size and quality of your yield.

Once you’ve nailed feeding your plants with these core nutrients, feel free to move on to a more complex feeding schedule to produce bigger, more potent harvests.

NUTRIENT REQUIREMENTS FOR SEEDLINGS, VEGGING, AND FLOWERING WEED PLANTS

Cannabis’ nutrient requirements change depending on which stage of life it’s in.

NUTRIENTS FOR CANNABIS SEEDLINGS

Cannabis seedlings get all their nutrients from their seed, and absorb water via their leaves as their root system develops (that’s why it’s important to keep them in a warm, humid environment).

You won’t need to start feeding your seedlings until they’re about 3–4 weeks old, at which point they’ll have developed 3–4 true leaves, thus entering the vegetative growth phase.

NUTRIENTS FOR VEGETATIVE CANNABIS PLANTS

Some growers opt to start their plants off on a light 2:1:2 fertiliser (there’s that NPK ratio) for one week just when their seedlings start to enter their vegetative growth phase. This step can be a great way to introduce your plants to their fertiliser and avoid nutrient burn. However, some growers see great results immediately starting their plants on a 4:2:3 fertiliser to kickstart growth.

By the mid-vegetative phase (roughly 6 weeks after germinating), you’ll want to aggressively increase your plants’ nutrients to help them develop strong, healthy foliage. Most growers opt for a 10:5:7 fertiliser by this stage.

These heightened levels of nitrogen will help your vegging plants produce luscious, green foliage and develop plenty of bud sites in time for flowering.

Towards the end of the vegetative phase, it’s a good idea to start lowering your nitrogen levels and preparing your plants for the switch to their bloom booster. Most growers use a 7:7:7 fertiliser in the last week of the vegetative phase.

Veg feeding recommendations:

  • Early veg: 2:1:2 – 4:2:3
  • Mid-veg: 10:5:7
  • Late veg: 7:7:7

NUTRIENTS FOR FLOWERING CANNABIS PLANTS

Flowering cannabis plants need less nitrogen and more potassium to promote the growth of big, resinous flowers. During the first two weeks of flowering, most growers feed their flowering plants with a 5:7:10 fertiliser. From here on out, it’s common practice to keep dialling up the nutrients on all fronts, always keeping potassium concentrations higher than the rest. By mid-flowering, most growers will be using a 6:10:15 nutrient solution.

During the last weeks of flowering, growers will drive down their nutrients to smooth out the transition to the pre-harvest flush. By this stage, it’s common to use a milder fertiliser with an NPK ratio of 4:7:10.

Flowering feeding recommendations:

  • Early bloom: 5:7:10
  • Mid-bloom: 6:10:15
  • Mid–late bloom: 4:7:10
  • Late bloom: pH balanced flush

HOW TO READ A FEED CHART: HOW OFTEN SHOULD I FEED MY WEED PLANTS?

Most fertiliser brands provide their customers with feed charts. Understanding these charts is the key to providing your plants with the right nutrients at the right time.

A feed chart will typically set out a 12–13-week growing cycle.

The weeks of the cycle will usually be listed along the x-axis of the chart, which might also include information like the photoperiod for each week and more.

Most importantly, your feed chart will outline what nutrients to give your plants, in what ratio, during the different weeks of their life cycle. Nutrients are typically applied once a week, and most fertiliser brands will provide you with a ratio of feed to water (either in litres or gallons). Some feed charts might also provide you with an EC or PPM range for their solutions. If so, invest in an EC meter and measure your nutrients before feeding for extra accuracy.

Once you’ve fed your plants, it’s always a good idea to check the conductivity or/and PPM of your soil to ensure your plants are absorbing nutrients properly.

HOW TO PREPARE CANNABIS NUTRIENTS

A potential nutrient slip-up, after all, can completely thwart your harvest. But feeding your cannabis plants can be very straightforward. Just follow these steps:

  1. Prepare your water. If possible, heat your water to about 19 – 21 °C to increase absorption by the roots.
  2. Add your nutrients according to the instructions on your fertiliser, and stir. Use a PPM or EC meter to get exact readings.
  3. If necessary, adjust the pH of your feed using a nitric or phosphoric acid pH down supplement.
  4. Once your PPM, pH, and temperature are right, feed your plants and measure your runoff using your PPM or EC meter to ensure your plants are taking up their nutrients properly.

How to Use Cannabis Nutrients

THE IMPORTANCE OF PPM, PH, AND WATER TEMPERATURE

EC is abbreviation or electric conductivity, PPM for parts per million. 

Both are used for a measurement of how much nutrients are present in your water or grow medium. To avoid over or underfeeding your plants, it's a good idea to always measure EC or PPM of your soil or grow medium to see if it still contains nutrients. If there are nutrients present in your medium at the time of your next feed, subtract your medium’s values from values recommended by your feed chart to avoid overfeeding.

pH and temperature are equally important metrics when feeding your plants. If either is off even slightly, your plants might struggle to absorb their nutrients. Hence, whenever it’s feeding time, keep your nutrient solution at the pH suggested by your fertiliser brand and your water temperature at 19 - 21°C.

TIPS FOR BETTER FEEDING

Here are some quick tips to ensure feeding goes off without a hitch.

Embrace chelation

Most high-quality nutrients will contain chemical chelates. If you’re an organic grower, you can use natural chelates like fulvic and humic acid to help your plants better absorb mineral nutrients like iron or zinc. Chelates work by surrounding positively charged nutrients with a negative or neutral charge, allowing them to pass through the plant pore barrier.

Try foliar feeding

Foliar spraying—spraying cannabis leaves with a fine mist—can be a great way to tackle nutrient deficiencies or pests/disease. It is also particularly effective for short-term feeding with secondary nutrients like magnesium or calcium, or micronutrients zinc, iron, and manganese.

Always flush

Nutrients are super important, but you don’t want any of them leftover in your harvested bud. That’s why it’s important to flush your plants with pH-neutral water for at least one week before harvesting. Flushing forces your plants to consume any leftover nutrients they’ve stored, resulting in a clean, smooth smoke.


Ready to boost your yields? Download our guide for pro feeding tips!

Free RQS
Grow Guide!

Stay cultivated! Gg_book
Get free guide

Over or underfeeding can stress and damage your cannabis plants. Make sure you keep your eyes peeled for the following nutrient-related problems.

Spotting nutrient issues early can save your plants. Watch our video, 'How to Detect Deficiencies on Cannabis Plants,' below for expert tips  on how to easily detect deficiencies in your cannabis plants and correct them with the right nutrients.

Video id: 207447241

PH IMBALANCE

  • pH issues can be caused by imbalances in your medium, water, and nutrients.
  • pH imbalances can dramatically impact the health of your plant and cause many other issues, such as nutrient lockout, deficiencies, and more.
  • If left untreated, pH issues dramatically impede the growth of your plants and will drive down both your harvest size and quality.

NUTRIENT BURN

  • Nutrient burn is usually caused by overfeeding or nutrient buildup in the grow medium.
  • Plants develop dark green leaves with almost neon green tips that bend upwards almost 90°, and deep red, magenta, or purple stems or branches.
  • Flowering plants develop yellow calyxes and sugar leaves before dying back rapidly.
  • Typically treated by flushing roots with pH-neutral water for at least one week before gradually reintroducing the fertiliser.
  • Measuring PPM and EC can help you avoid nutrient burn.

Nutrient Burn on a Cannabis Plant

NUTRIENT LOCKOUT

  • Nutrient lockout is caused by nutrient buildup around a plant’s roots, or by pH imbalances, and prevents them from absorbing available nutrients.
  • Nutrient lockout leads to nutrient deficiencies, which can cause yellowing foliage, burnt leaf tips, irregular leaf shape and size, and brown spots. Symptoms vary depending on which nutrients your plant is missing.
  • Typically treated with a flush, pH checks, and nutrient adjustments.

OVERFEEDING

  • Overfeeding with chemical fertilisers and boosters can burn your plants.
  • The highly concentrated nature of chemical fertilisers means novice growers can easily end up overfeeding their plants.
  • Telltale signs of overfeeding include dry, burnt-looking leaves with yellow or brown discolouration, burnt edges, and upward bent tips.
  • Rookie growers often end up buying more supplements in an effort to remedy existing nutrient problems, which only makes matters worse.
  • Overfeeding needs to be treated quickly with a root flush, pH stabilisation, and a new feeding schedule.

Overfeeding on a Cannabis Plant

NUTRIENT DEFICIENCY

  • Nutrient deficiency can be caused by underfeeding, or by nutrient lockout.
  • Deficiencies in nitrogen, phosphorus, potassium, or secondary nutrients can cause symptoms like dry foliage, yellow or brown leaves, and discoloured stems.
  • Nutrient deficiencies are treated by increasing/introducing more nutrients, or by first remedying nutrient lockout.

ORGANIC VS CHEMICAL FERTILISER FOR CANNABIS

At RQS, we always encourage the use of organic nutrients over chemical fertilisers. Unlike synthetics, organic nutrients are released into the soil and absorbed by your plants much slower, dramatically reducing the chance of nutrient burn or other feeding issues.

Organic nutrients also benefit the soil itself, supporting the development of a rich ecosystem of microorganisms that protect and work in tandem with your plants.

Organic soil also gets better with time, making it ideal for outdoor growers.

The fact that organic nutrients don’t produce toxic runoff also reduces the impact your harvest has on the environment.

And while we’re all about organics here at RQS, we do understand that chemical fertilisers also have their pros. First and foremost, they are absorbed much faster, meaning they’re better for situations where efficiency is key (like when treating a deficiency, for example).

The fact that synthetic fertilisers are carefully made to exact specific ratios of nutrients also means you have a lot more control over what your plants “eat”, and in what doses.

BENEFITS OF ORGANIC NUTRIENTS

  • Less impact on the environment
  • Boosts soil quality and health
  • More sustainable than chemical fertiliser
  • Better taste (some say)

BENEFITS OF SYNTHETIC FERTILISER

  • Absorbed faster
  • Nutrient ratios are dialled-in (more control)
  • More accessible

WRAPPING YOUR HEAD AROUND CANNABIS NUTRIENTS

With the right genetics, just enough nutrients and water, and plenty of light, you’re well on your way to growing some exceptional weed. Remember, arguably the biggest weapon in your arsenal is experience, so keep honing your skills and reaping the rewards.

Grow Guide Topic Finder

eKomi silver seal
4.7 out of 5
from 44983 reviews

Cookies settings

We are requesting your permission to use your data for the reasons stated below:

Functional cookies

Functional cookies help our website to function optimally and allow us to personalise certain features.

Preference cookies

Preference cookies allow us to remember information that influences the way our website looks, including your preferred language based on your region.

Analytical cookies

Analytical cookies give us insights into website traffic and customer behaviour, including how many people visit our site, how long they browse for, and which parts of our site they visit.

What are cookies?

Cookies are small pieces of data from a particular website that get stored on a user’s computer while they’re surfing the internet. Cookies have several different functions. Some of them track browser activity that enables businesses to deliver targeted advertisements. Other cookies serve to remember user login details to different websites to make jumping on social media, or other sites, a more fluid process. Because each cookie has its own unique ID, these pieces of data allow website owners to measure the unique traffic coming into their site.

Why do we use cookies?

Cookies come in handy when you visit our website. They ensure you stay logged in, that you can shop safely, and that the items you add to your cart stay there before you make a purchase. But cookies also help us. The data they provide allow us to improve our website and enable us to present you with targeted advertisements that are compatible with your interests.

What kind of cookies do we use?

Functional cookies

Functional cookies help our website to function optimally and allow us to personalise certain features.

Preference cookies

Preference cookies allow us to remember information that influences the way our website looks, including your preferred language based on your region.

Analytical cookies

Analytical cookies give us insights into website traffic and customer behaviour, including how many people visit our site, how long they browse for, and which parts of our site they visit.

How can I disable or delete cookies?

Not a fan of cookies? No worries. You can disable them (with the exception of necessary cookies) in your browser settings. However, blocking cookies may impact your browsing experience and prevent you from enjoying all of the technical features of our site.

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: