Cannabis Grow Guide by Royal Queen Seeds

By Luke Sumpter

Want to grow medical marijuana? If so, get ready to undertake a transformative journey!

Growing weed at home comes with a bunch of benefits; you get to choose what strains to grow based on the tastes and effects that appeal to you, and you’ll start to develop a green thumb as you tumble down the horticultural rabbit hole.

Not much beats the satisfaction of harvesting and enjoying your own buds.

Why Grow Your Own Medical Marijuana?

While recreational growers can achieve their goal (getting high) using just about any form of cannabis, medical users often have a more detailed list of effects and traits that they’re looking for.

Growing your own enables you to experiment and tinker.

Control and Self-Sufficiency

Many of us live in areas where cannabis remains prohibited. We’re limited to street weed, where every purchase feels like a shot in the dark. This becomes especially problematic for medical users who need a consistent supply of good-quality and unvarying material.

Growing cannabis cuts out the middleman. You have free reign over the tastes, smells, and effects of your buds. Not only that, but you’ll develop self-sufficiency.

Save money in the long run

If you are looking for a regular supply, growing your cannabis ultimately means saving money. Remember, you will be eluding the intermediary.


Cannabis quality varies dramatically depending on the source. Dispensaries offer properly dried, cured, and manicured flowers. If you’re used to street cannabis, you’ve probably come across your fair share of wet, mouldy, and seedy buds. You also run the risk of exposing yourself to pesticide contamination when purchasing weed from a shady source.

Growing your own organic plants will enable you to sidestep the aforementioned issues and ensure top-tier quality.

Tailor Your Flower to Your Condition

Environmental variables also impact chemical composition, meaning cannabinoid and terpene content can fluctuate among different plants of the same strain.

Many medical marijuana users eventually discover a blend of terpenes and cannabinoids that works best for them. Growing medical marijuana will help you hone in on the most effective cultivar for your condition.

A Hobby Like No Other

Spending time in your grow room makes time stand still, and nothing beats walking around the garden with the sun on your skin and terpenes in the air.

Prepare to wear many hats during your medicinal marijuana growing journey. You’ll play the role of a physiologist as you begin to understand the endocannabinoid system and how weed works in the body. You’ll also delve into the world of soil biology as you start to understand the soil food web and how tending to life in the growing medium results in healthier plants. Heck, you might even choose to dive deep into the domain of biochemistry as you become enthralled by the entourage effect, and plant biology when you become fascinated by terpene biosynthesis.

Growing Medical Marijuana: Equipment Rundown

If you’re ready to take the leap, you’ll need to get your hands on the right equipment to make the endeavour possible. Of course, your budget will dictate what items you choose to buy.


An indoor setup can range from a small tent designed to cultivate a personal stash to large grow rooms that produce enough weed to get your neighbourhood stoned.

  • Grow tent: A high-quality 120 × 120 × 200cm tent will set you back around €100. If you need something smaller, expect to splash out €85 on a 60 × 60 × 140cm grow tent.
  • Grow light: A good-quality full-spectrum LED grow light with cooling fans and hangers costs approximately €110.
  • Seeds: Seed packs vary in price depending on the strain and the quantity. As an example, a pack of 5 Stress Killer Automatic seeds costs € 37.50 from the Royal Queen Seeds shop.
  • Pots: There are plenty of pots out there to choose from. RQS Geotextile Fabric Pots promote healthy root growth and excellent aeration. And it costs only €8 for the 19-litre pot.
  • Easy Start seed starter pots: Boost your germination rate with RQS Easy Start at €6.95 per pack.
  • Fan: Indoor plants need a steady supply of fresh air. Expect to pay around €30 for a good-quality fan.
  • Exhaust: You can purchase a 100mm 30W inline fan for approximately €55 to keep the fresh air flowing.
  • Hygrometer: These devices help you track the temperature and humidity in your grow tent for around €13.
  • Potting soil: A 50-litre bag of potting soil will set you back around €15.
  • Organic nutrients: Organic nutrients help your plants tap into their full potential during your grow, but they require different feed at different stages of the growing cycle. Consider Easy Boost (€5.50), Easy Grow (€13.75), and Easy Bloom (€13.75).
  • Trimming scissors: Curved trimming scissors cost €10.95 and will help you prune, harvest, and manicure your buds.

In total, you’ll need to spend €407.40 on the equipment listed above. Then, you’ll need to consider the additional cost of extra pots, and how much electricity you’ll use to run the lights and fans.

Growing Medical Marijuana: Equipment Rundown


Growing outdoors eliminates the need for artificial lighting. You can also find temperature-controlled greenhouses, fancy polytunnels, and automated irrigation systems. However, for those looking to grow medical marijuana outdoors for the first time, the simple list below should suffice:

  • Seeds: Using Stress Killer Automatic as an example once more, you’ll spend €37.50 on five seeds.
  • Easy Start seed starter pots: Get your seeds off to the best start with this piece of kit for €6.95.
  • Pots: Outdoor growers have the luxury of transplanting straight into the ground. However, pots offer the benefit of portability; you can move your plants to safety during adverse weather. Fabric pots keep the growing medium well-aerated, and the 19-litre option costs €8 per pot.
  • Potting soil: A 50-litre bag of potting soil costs around €15.
  • Trimming scissors: Make your life easier at harvest time by investing €10.95 into this handy tool.
  • Nutrients: Make every stage of your plants' life cycle productive with Easy Boost (€5.50), Easy Grow (€13.75), and Easy Bloom (€13.75).

In total, you’ll spend €105.40 on the items listed above. Plus, you’ll need to spend a little extra on additional pots, and bits and pieces such as watering cans and trowels.


Choose Your Medical Marijuana Seeds

Now it’s time to undergo arguably the most important process of the whole operation: strain selection. With thousands of varieties to choose from, modern growers are spoilt for choice.

Photoperiod vs Autoflowering

When browsing for medical marijuana seeds in the RQS catalogue, you’ll come across the terms “feminized” (or “photoperiod”) and “autoflowering”. These terms merely refer to how a plant enters the flowering stage.

Photoperiod strains require a change in the light cycle to switch from vegetative growth into flowering. Reducing the light cycle indoors tricks plants into producing flowers in hopes of reproducing.

Autoflowers don’t depend on a light cue to start flowering. They simply begin flowering on their own after a set period (2-4 weeks), providing an easier entry route for beginners.

Autoflowers are also typically smaller and feature a much briefer growing cycle. For these reasons, autos usually catch the eye of novice growers.

You can successfully grow these stealthy plants in small, confined spaces and still harvest a rewarding yield at the end of the process. However, if you’re aiming for the biggest yield possible, you’ll want to browse photoperiod Sativa strains that reach heights of 3m and beyond.

THC Medical Weed Seeds

The cannabis plant contains over 100 cannabinoids. THC and CBD are the most abundant within the vast majority of cultivars available. As the main psychotropic component of cannabis, THC catalyses the high associated with the herb. As well as providing an enjoyable recreational experience, some medical marijuana users find great relief when using high-THC strains.

CBD Medical Cannabis Seeds

As opposed to THC, CBD produces no psychotropic effect. In fact, it even takes the edge off the effects of THC. Ongoing studies are exploring the potential of this cannabinoid for myriad conditions, and many medical marijuana growers value the clear-headed and functional effect of high-CBD flowers.

Different THC:CBD Ratios

If you enjoy both THC and CBD, you can grow strains that allow you to experience the best of both worlds. You’ll find plenty of strains in the Royal Queen Seeds library that offer equal, or otherwise unique, quantities of THC and CBD, including Medical Mass.

Novel Cannabinoids

As far as cannabis breeding goes, we’re currently experiencing the tip of a very big iceberg. At Royal Queen Seeds, we’ve made some pioneering steps to create strains that offer intriguing non-psychotropic cannabinoids like CBG and CBDV.

The Importance of Terpenes

Apart from cannabinoids, cannabis flowers also produce many other chemicals of interest, including terpenes. These aromatic molecules underpin the unique flavours and aromas of each strain.

Beyond flavour, though, terpenes play a much more significant role. They directly influence the effect of each strain. While limonene helps to clear the head and impart an energetic feeling, myrcene contributes a stoning and relaxing sensation. Take the effects of terpenes into account when selecting a medical marijuana strain.

Choose Your Medical Marijuana Seeds

Growing Medical Marijuana: A Guide

You made it this far. You have all of the gear, a newfound knowledge of medical marijuana, and now you’re rearing to go. Below, you’ll find out how to facilitate those seeds into large plants bending under the weight of their own buds!

Where To Grow Medical Marijuana

Wherever you’d like! Well, within the context of draconian laws.

You’ll have much more control over an indoor growing environment, while outdoor plants are exposed to adverse weather, pests, and nosey neighbours. But running lights, humidifiers, and fans certainly costs more money to run.

But you don’t need a spare room or a south-facing idyllic garden to grow weed. You can get inventive and grow almost anywhere, from balconies and rooftops to abandoned meadows and forest clearings.

A Few Tips for Your Medical Cannabis Garden or Grow Room

1. Avoid pesticides

At Royal Queen Seeds, we recommend an organic approach. Not only does this help to minimise pesticide exposure while using cannabis, but it stops pesticides from leaking out of our gardens and damaging the wider ecosystem.

Neem oil serves as a completely natural way to defend your cannabis plants against some pests.

Propolix Fungicide offers growers an all-natural way to eliminate annoying fungal varieties.

2. Harness Microbes To Mimic Nature

Nature knows best. Plants don’t grow in isolation in the woods. Instead, a large symbiotic web of life ensures everything thrives. By applying mycorrhizal fungi and beneficial bacteria to your soil, you’ll improve nutrient uptake, pathogen resistance, and overall soil health and structure.

A Few Tips for Your Medical Cannabis Garden or Grow Room

3. Transmute Waste Into Black Gold

Initially, you’ll need to purchase potting compost. But going forward, you can cut out this cost by composting your kitchen scraps and cardboard waste.

The key to good compost? Aim for a balance of materials. A 1:1 ratio of brown to green material works well. While the brown material acts as a source of carbon, the green material adds nitrogen to the pile.

4. A Word on Watering

Many beginner growers often overwater their plants. It might sound harmless, but it can significantly increase the chances of root rot. To avoid overwatering, we recommended following a general rule of thumb: simply wait for the top 5cm of soil to dry out before watering again.

You can also weigh your plant containers to get an idea of how much water remains in the growing medium. Weigh your plant immediately after watering, and again a day or so later. When the majority of the water weight has dissipated, you’ll need to top up your plants again.

How To Grow Medical Marijuana

There is no difference between growing high-TCH than High-CBD plants. They will behave just the same.

Are you ready to put the tips into action?


To trigger germination, you’ll need to expose your seeds to damp conditions. Seeds also respond better to favourable temperatures. Aim for the conditions below to optimise seed germination:

  • Temperature: 22–25°C
  • Relative humidity: 70–90%

At Royal Queen Seeds, we recommend using our Feminized and Autoflowering Starter Kits. They contain everything you need to successfully germinate seeds.


Vegetative Stage

During the vegetative stage, plants put their energy into producing large fan leaves, branches, and stems. Once your seedlings develop a few true leaves, you’ll need to transplant them into a larger home.

  • Potting mix: You’ll need to create a light potting mix suitable for the type of plants you’re growing. Photoperiod strains enjoy more of a rich growing medium, whereas potting mixes for autoflowers should feature higher quantities of perlite, peat moss, and vermiculite, and less compost. In either case, vegetating plants have a high demand for nitrogen.
  • Nutrients: At the start of the vegetative phase, we recommend mixing 50–100g of Easy Boost in every 20 litres of soil, along with the beneficial microbes mentioned above. Throughout the rest of the veg phase, Easy Grow Booster Tablets will help to fulfil your plants’ nutritional requirements. Because autos don’t require as much nutrients, you should half the recommended dose of each product.
  • Lighting: Plants grow fast during veg, so you’ll need to maintain a consistent distance between the top of the canopy and your light source. When it comes to timing, keeping your lights on for 18 hours and off for 6 hours in a consistent cycle will help to fuel adequate growth during vegging.
  • Humidity: Vegging plants thrive in a relative humidity of 40–70%.
  • Temperature: Aim to maintain a temperature between 20–26°C.
Vegetative Stage

Flowering Stage

Things start to get extremely exciting during the flowering stage. If you’re growing autoflowering plants, they’ll happily cruise into flowering under a 18/6 light cycle right up to harvest. If you’re growing a photoperiod variety, growing indoors you’ll need to switch to a 12/12 light cycle to initiate and maintain flowering. If you are growing outdoors, mother nature will dictate the plant when to enter the blooming phase (around mid-July).

  • Change nutrients: Flowering cannabis plants require less nitrogen and more phosphorus and potassium. For this reason, you need to switch to Easy Bloom during the flowering stage. Again, half the dose for auto plants.
  • Humidity: Reduce relative humidity to 40–50% to minimise the risk of mould.
  • Temperature: Aim to maintain a steady temperature of 26°C.
Flowering Stage


Stop feeding your cannabis plants two weeks before harvest. This will prompt them to use up all of the residual nutrients within the growing medium and their cells, resulting in an improved taste and smoother hits.



Harvest is all about timing. Keep an eye on these key signs to know when to pull the plug:

  • Fan leaves will start to turn yellow due to flushing.
  • Those small, sparkly gems (trichomes) on the flowers will change in appearance, switching from translucent to milky. Use a pocket microscope to keep track of their maturity.
  • See those stringy structures on your buds? They’re called pistils. They’ll become darker in colour when it gets closer to harvest time.

Once you’ve determined that the time is right, you’ll need to physically harvest your buds. Some growers cut small plants at the base and hang the entire thing up to dry. Others prefer to use trimming scissors to detach each flower before drying and curing. This can be done in one fell swoop, or over several days for a progressive harvest.


Drying & Curing

You’ve harvested your flowers. Now, you need to protect them from mould, extend their shelf life, and enhance their flavour.

Drying & Curing

How To Use Medical Marijuana

Now for the best part! You can finally put the fruits of your labour to use. Just like there are numerous strains and many different ways to grow weed, there are plenty of ways to enjoy it. Check out some of the most popular ways to use medical marijuana below.


Smoking a joint serves as perhaps the most quintessential way to use cannabis. Many users find the process of grinding, rolling, and smoking to be ritualistic and therapeutic. This administration method offers a quick onset of effects as cannabinoids and terpenes gain instant access to the bloodstream. However, it comes with the obvious downside of health-damaging carcinogens.


Vaping utilises lower temperatures than smoking. Instead of burning plant matter, it heats flowers enough to release phytochemicals such as cannabinoids and terpenes. Vaping offers a similar rapid onset of effects, just without exposure to carcinogens.

Edibles (Oral)

You can use your harvest to get creative in the kitchen. By decarboxylating your buds and cooking up a batch of cannabutter, you can infuse cannabinoids into almost any dish, from brownies to pasta sauce. However, keep in mind that edibles offer a much more potent high. Oral cannabinoids pass through the liver, where it transforms THC into the more powerful psychotropic molecule 11-hydroxy-THC. Prepare for a longer-lasting and more intense experience.


Not in the mood for cooking? How about making extracts? Oils and tinctures are a handy way to take cannabinoids at home and on the go. Plus, you can use them to take advantage of sublingual administration. This route involves placing products under the tongue. Here, they diffuse through the thin layer of tissue and directly into the bloodstream, resulting in a fast onset of effects while bypassing the liver.

Remember: Anyone Can Grow Their Own Medical Marijuana

You’ve got this. Growing medicinal marijuana doesn’t take some magical ability. You’ll gain new skills and insights with each grow. Eventually, you’ll develop a personalised method that allows you to successfully achieve productive plants every time. Happy growing!

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