How to Grow Giant Cannabis Plants

Last updated: 3 December 2021

How to Grow Giant Cannabis Plants

There was a time when only weed farmers were capable of growing huge cannabis plants. You’ve probably seen the Instagram photos of crops so big that they look more like oak trees than our beloved ganja. But nowadays, the recreational grower is blessed with an abundance of options and strain choices, meaning that growing a huge cannabis tree is no longer out of reach. In this article, we highlight the most important factors of growing giant cannabis plants and tell you how to go about it.

How Big Do Cannabis Plants Get?

How Big Do Cannabis Plants Get?

The final height of your cannabis plant will mainly be dictated by its genetics and whether you’ve chosen to grow them outdoors or inside. Outdoors, cannabis is capable of growing much larger than indoors. The average height of a cannabis plant is 120cm (3’11”), although this can vary wildly based on those genetic factors.

The maximum possible height for a cannabis plant is around 400cm (13ft). The plants capable of growing this tall are normally strains that have Sativa dominance. Strains that are Indica-dominant normally only grow to 200cm (6ft) in height, although again, this can vary a huge amount based upon the genetic heritage of any given strain.

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Tips on Growing Giant Cannabis

It’s time to get down to the good stuff. To grow huge cannabis plants, we’ve compiled a list of 10 essential factors that need to be addressed. These will hold true whether you decide to grow indoors or outside. They are:

1. Pick the Right Strain

Genetics play the most important role in growing large cannabis plants. Therefore, your choice of strain will be the biggest decision you make for your upcoming grow. Indicas and Indica-dominant hybrids tend to grow bushier and top out between 100-200cm (3-6 ft), while some exceptional Sativa strains can reach upwards of 400cm (13ft) and grow tall and slender – a bit like a Christmas tree. To give you a gentle nudge in the right direction, we’ve included a short list at the end of this article with five strains capable of growing into ginormous specimens.

2. Give the Plant Enough Space

We all like a bit of space, and it’s no different for your cannabis plants. They are capable of detecting what’s situated in their surroundings and will grow accordingly. More space means more room to stretch. This also has the added benefit of improved air circulation, which is a crucial factor in strong plant growth. Moreover, it will allow for greater absorption of light. Your plants won’t be inhibited for space and so can stretch their solar panel-like leaves out to receive the light.

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3. Bigger Pot = Bigger Plant

Never underestimate the importance of pot size! In order to grow into a giant cannabis tree, your plant will need a huge, sprawling root structure to support it. Just remember that once full of soil and with a massive tree sticking out of it, your pots will nearly be impossible to move. If your plants need to be mobile, consider placing your pots on a set of wheels beforehand. Also, cannabis thrives in well-draining soil, so make sure your chosen pots have holes in the bottom. Alternatively, plant directly into the ground for unlimited potential for root growth.

4. Pick a Quality Medium

In order to grow your cannabis plants to their potential, your choice of medium is paramount. The best mediums for growing cannabis are soil, soilless (such as coco), or hydroponic. We’d recommend going with an organic soil approach and growing outdoors in order to obtain giant cannabis plants. It would be even better to use a “super soil” that contains most of the essential macro and micronutrients in a slow-release form that your plants will require for the entirety of their lifespan.

5. Give Plenty of Light

It’s no secret that plants require plenty of light to thrive. If you’re growing indoors, make sure your lights are not only bright enough, but also at the optimum distance from your canopy. You can use a light meter here to really dial things up to their maximum potential. If you’re operating with lights that lack power output, consider upgrading to something stronger. Meanwhile, if you want to grow a huge outdoor cannabis plant, make sure it’s situated where it will receive the maximum amount of sunlight hours possible.

6. Extend the Vegetative Stage

Extend the Vegetative Stage

Humans are great at manipulating environments to suit their needs, and some serious manipulation is required to grow huge cannabis plants. If growing outdoors, it’s necessary to start your cycle indoors at the end of winter. Germinate your seeds in February and nurse them indoors until the weather improves and spring is in full swing. Then, you can move your ladies to their outdoor mediums. If growing indoors, consider keeping your plants under vegetative lighting for a longer period of time than normal, although you’ll need to be aware of space limitations as your plants continue to stretch in the early stages of flowering.

7. No Feed = No Growth

All plants require the macronutrients of nitrogen, phosphorous, and potassium to survive and thrive. They will use more nitrogen in the vegetative stage and more phosphorous and potassium in the flowering stage. Target faster vegetative growth with nitrogen-based supplements while your plant is in full growth mode. Switch to phosphorous and potassium after your plant has finished stretching. Just remember though that too many nutrients can have a detrimental effect on your cannabis, so less is sometimes more, and always follow the manufacturer’s dosage guidelines.

8. Train Your Plant

There are a couple of training techniques we advise to grow a huge cannabis tree. Topping is a beginner-friendly method that takes away growth from a single, dominant head. This allows for more energy to be sent to competing branches, resulting in more uniform growth and better bud production. You’ll also want to effectively trim your plants. By pruning the lower areas that don’t receive much sunlight, you will direct more energy to the canopy of the plant, where all the serious growth and bud production takes place.

9. Stake the Plant

Stake the Plant

Sometimes, you’ll grow giant cannabis plants so big that they want to fall over. You can prevent this by driving a stake into the ground near the main stem of your plant. Use this to hold your plant upright. This will also encourage vertical growth. You may even wish to pull branches apart in different directions to allow extra light to penetrate your canopy.

10. Choose Seeds of Giant Cannabis Plants

As we mentioned earlier, genetics is the most important factor when it comes to growing large cannabis plants. To take out the guesswork, here are five of the largest strains of cannabis available today, all capable of growing in excess of 3 meters (10ft) in height:

Strawberry Amnesia (Herbies Seeds) Strawberry Amnesia (Herbies Seeds)
  • Photoperiod
  • Electric brain buzz
  • 600 - 700 g/m² indoors
    700 - 1200 g/plant outdoors
  • 22 %
View strain

Strawberry Amnesia (Herbies Seedbank)

This monster cross between Strawberry Cough and Amnesia has lent this delightful strain some top-quality genetics, meaning she’s capable of growing nearly 3 meters (10ft) tall outdoors. Strawberry Amnesia is a 75% Sativa-dominant strain that’s packed with 22% THC. When smoked, this bud induces a powerful head high that’s both uplifting and euphoric.

GG#4 Original Glue (Kera Seeds) GG#4 Original Glue (Kera Seeds)
  • Photoperiod
  • 25 %
  • Power that beats everything
  • 500 g/m² indoors
    1000 g/plant outdoors
Out of stock
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GG#4 Original Glue (Kera Seeds)

Despite sitting at 60% on the Indica side, GG#4 Original Glue is another supercharged strain capable of reaching 3 meters (10ft) when grown outdoors. The 25% THC levels are guaranteed to knock your socks off, inducing a powering high that hits right between the eyes. This gigantic plant will need plenty of space to grow, but you’ll be rewarded with lovely, powerful lemon fueled-scented buds.

Y Griega (Medical Seeds) Y Griega (Medical Seeds)
  • Photoperiod
  • 500 g/m² indoors
    500 - 600 g/plant outdoors
  • 27 %
  • Increased charge of energy
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Y Griega (Medical Seeds)

This whopping medical-grade strain grows up to 3.5 meters (11.5ft) outdoors when left to do her thing, producing strong buds coated with 27% THC. Being 80% dominant on the Sativa side, Y Griega performs equally well indoors as she does outside, although you may need to employ some serious training techniques to keep her under control. One puff of this wonder strain delivers an incredible jolt of energy.

Goldmine (Heavyweight Seeds) Goldmine (Heavyweight Seeds)
  • Photoperiod
  • A mine full of delight
  • 22 %
  • 500 - 600 g/m² indoors
    1000 g/plant outdoors
Out of stock
View strain

Goldmine (Heavyweight Seeds)

You’ll understand where Goldmine got her name after growing one of these monsters for yourself, as she grows between 2-3 meters (6.5-10ft) in height outdoors and is capable of yields of 1kg (35oz) per plant. This 70% Indica cross is packed with 22% THC. Expect strong and pungent tropical fruit flavors with skunky undertones, complemented by sweet flavors of berry and honey. The effects are happy and relaxed, although too much of the stuff will have you glued to the couch.

1024 (Medical Seeds) 1024 (Medical Seeds)
  • Photoperiod
  • 20 - 25 %
  • Pure Energy
  • 600 g/m² indoors
    600 - 800 g/plant outdoors
View strain

1024 (Medical Seeds)

Another Sativa-dominant strain at 70%, this beast is capable of reaching dizzying heights, stretching to 3.5 meters (11.5ft) if you allow her to. She comes loaded with 20-25% THC thanks to her Chilean and Spanish genetics. The flavors and aromas are sweet, spicy, fruity, and musky, while the effects are dominated by surreal bursts of energy.

Can I Grow Big Cannabis Plants?

You can grow big cannabis plants at home by following just a few basic rules. Choose an outstanding, large-growing strain with awesome genetics, then give that plant ample room to grow. Pick a quality medium, give your plant plenty of light and nutrients, and employ some relevant training techniques.

What are your to-go enormous strains? Share them along with your secrets to grow large weed plants in the comments below!

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Brilliant article, and your tips as always are fabulous!
Ive grown a few monster plants in my day, I have to admit it does require a lot of work. My biggest plant was about 9 feet tall and and 8 feet wide in the middle, it was heavily topped, giving it an incredible amount of top buds. I pulled a whopping pound and 5 ounces from that one plant.Marijuana is a living, breathing creature that is well aware of its environment. Treating a plant with lots of respect, talking to it and being nice by giving it lots of food and water really helps. If your nice to the plant, It rewards you with the fruits of your labor.
Great tips !!!
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