How to Support a Giant Outdoor Cannabis Plant: Ties, Stakes, Netting and Soil

An outdoor cannabis plant can hit 4 m (13 ft) with branches 2 m (6.5 ft) long, but it only gets there in one piece if you hold it up: regular ties, stakes from the first weeks and a trellis net that spreads the weight. Add the right genetics, a huge volume of living soil, smart pruning and some extra light at the end of summer, and you've got the full recipe for a monster plant.

Since growing is always about chasing giant plants, here's how to get there, from picking the strain to keeping a heavy plant upright, with some tips for ideal growth and flowering along the way.

Start with genetics that can go big

Picking genetics with strong growth is step one, because almost the plant's entire structure depends on it.

Sativas are known for growing a lot bigger, with wider spacing between nodes and a thinner, more stretched-out structure. Indicas, on the other hand, stay at a much more manageable size, with tight node spacing, way more side branches and a sturdy main stem.

Indica-sativa hybrids show traits from both sides, though depending on the parents used in the cross and which genetics dominate, they can lean one way or the other. As a rule of thumb, the biggest plants come from genetics that are more than 60% sativa, while indica-dominant crosses give you somewhat more compact plants with more branching.

Now to the good part: which strains are best for growing giants? Here are a few that'll get you monster weed:

• Moby Dick
• Chronic
• Monster
• Amnesia Cactus
• Amnesia Haze

You'll also find seeds from strains with Skunk genetics. We recommend these for beginners going into their first grow:

• Power Kush
• Industrial Plant
• Big Kush
• Critical Jack
• Critical +2.0
• Critical +
• Critical Cheese
• Cheese
• Orange Juice
• Purps #1
• Purple Moby Dick
• Original Amnesia
• Kush'N'Cheese

Tying: keep a big plant from falling over

Tying doesn't just keep the plant from toppling: it also lets you shape it and steer where it grows, so it fills out like a big bush instead of shooting up like a pine tree.

It goes without saying that tying is key to growing giant cannabis plants. Some growers even build wire frames. It's also vital for holding together all the branches that will grow side by side into one massive monster plant. Always tie big plants with flexible materials that let them sway naturally and don't strangle them.

We also recommend redoing the ties every 15 days.

Stake your cannabis tree to make it stronger

Staking is essential if you want giant cannabis, so start from the plant's first days. Stake the main stem first and the branches after that; with that support they'll give you bigger harvests, because they won't be bearing crushing weight.

Once the plants hit the production levels you're after, the stakes you put in might not be strong enough to hold the weight, so we recommend switching to trellis netting. That way each branch is supported with less strain, since the total weight is spread across the whole structure. It's easy to set up, too: stretch the net over the giant plant and thread the branches through the holes, so the weight gets distributed and light can get all the way down to where each branch starts.

The best growing medium for giant cannabis buds

According to plenty of growers who've pulled off huge cannabis plants, the container matters, because that's where the plant will grow and reach its max size. That's why they need a lot of room: the estimate is roughly 1,000 to 1,500 L (about 265 to 400 gallons) of soil per plant.

As everyone knows, the soil is one of the most important factors for big cannabis plants. It's one of the main keys to a truly productive plant or grow, so the more space the roots have to develop properly, the better the growth.

If you don't have the space for a full-on in-ground grow, you can use fabric pots, which keep things more organic and give the growing medium all the oxygen it needs, so the plant develops much better because it can actually use every resource you give it.

How to prepare soil for big cannabis plants

For an organic soil mix you'll need Trichoderma and mycorrhizae to apply to the roots; light and dark peat at 30% each; and sphagnum moss, coco coir, worm castings and perlite at 10% each. Top it off with a layer of biochar and straw to keep moisture from evaporating.

Netting

Nets are a great way to keep things stable: as the plant grows, they act as an internal frame holding up the branches of big cannabis plants. On a 4 m (13 ft) plant you can have branches 2 m (6.5 ft) long or more.

It's a good idea to add a new net over the plant every month, ScrOG-style, threading the branches through the holes to lock the structure in place. And the bigger your monster plants get, the more the netting matters: it keeps the branches together so they don't sprawl and flop over.

Pruning

Giant cannabis plants need pruning: it's a really important tool to use, just not to overuse. Every time you prune, you're holding back vegetative growth or pausing the plant's normal development so it can push out new shoots.

Pruning is what decides whether you end up with a pine tree shape or a bush.
Pruning early on is a good move to help the plant build the base structure of the future giant.

Light

If you're going for a monster plant but didn't start in September (Southern Hemisphere; that's March up north), so you've only got a few months of vegetative growth left, or you've got a fast-flowering sativa strain, there's a fix to boost growth: artificial light.

You can add it toward the end of summer to keep the plant from starting to flower. Just leave the light on until you hit about 16 straight hours of light, counting natural daylight.