The Best Way to Trellis Outdoor Cannabis Plants

By Kyle Ladenburger
Published: January 19, 2021 | Last updated: July 21, 2022 07:15:39
Key Takeaways

If your growroom’s parameters are on point, indoor cannabis has a pretty cushy life. Its outdoor cousin, on the other hand, has to deal with the whims of Mother Nature. 

Source: Photo by Dustin Fraser and Smart Pots

If you grow cannabis indoors or in greenhouses, you have a lot of control over your plants. You can manipulate the amount of light a plant receives, which in turn can shorten the plants’ growth cycle from seed/clone to harvest significantly. It also results in relatively smaller plants.

Growing cannabis in the great outdoors is a completely different story, as the plants are subject to the whims of nature itself. Flowering does not occur until the seasons change at midsummer, resulting in a much longer growing season (the outdoor growing cycle can easily reach anywhere from six to nine months, as opposed to three months indoors).

This means outdoor cannabis can get quite big, as most cannabis varieties are genetically predisposed to grow rather large.


One way to have a better grasp on your plants is to grow in containers instead of natural soil. This way, you can control what is in the growing media and avoid any possible inconsistencies or contaminants that may be present in the soil.

However, anyone who has grown any type of plant in containers outdoors will know that they are prone to toppling over, for one reason or another. Strong winds, heavy storms, or just the sheer top weight of the plant itself can be enough to cause the container to tip over.

Utilizing a larger container size can help add extra stability, but even that can cause problems. If the plant falls over and the container stays upright, the stems can bend and even snap.

An unexpected fall can lead to significant plant stress that can hinder overall production or yield and, in the worst cases, even total plant loss. Losing a plant to something as simple as it falling over is a foolish way to ruin a crop. Therefore, it’s important to have a strong, reliable plant support system.

Illustrated steps to support outdoor cannabis plants in large fabric containers.Below, I’ve outlined one way you can support your outdoor cannabis plants. This system is designed for and works best with larger fabric aeration containers, ranging from 100 to 1,000 gallons in size.


Step 1: Initial Support

A large, heavy-duty tomato cage is at the center of this system and it will provide the internal support for the main stem and branches. Install the tomato cage at the time of transplanting to avoid damaging the growing root system.

Step 2: Install T-posts

Install four metal T-posts equally spaced around the container (if an imaginary line is drawn from post to post, it would create a square around the circular container). Depending on the container size, the T-posts should be anywhere from six to 10 feet in length and anchored deep enough into the ground to provide maximum stability.

The T-posts are responsible for holding the entire structure upright, so do not cut corners with this step. To provide an extra level of support, the initial support caging can be tied to each of the T-posts.


Step 3: Add Horizontal Trellising

The horizontal trellising will have the job of supporting the upper branches of the plant, so use wire fencing or heavy-duty vinyl-coated wire caging with four to six-inch square holes as these will be strong enough to support the weight of the flowering plant.

Cut your chosen wire material into one or two square pieces large enough to touch the T-posts. Just above the tomato cage, hang the first square of caging horizontally by tying the corners to the T-posts with wire or a strong gardening twine. It is important that the horizontal trellising be as secure as possible to ensure proper support of the upper branches.


For enhanced support, install a secondary horizontal trellis about one or two feet above the first. Each section of the horizontal trellising should be in place before the growing branches reach it. This will allow them to easily grow into the caging’s holes.

Steps 4 & 5: Creating the Outer Caging

The outer caging is there to help support the outward, lateral growing branches. Use the same wire fencing or heavy-duty vinyl-coated wire caging that was used to create the horizontal trellising. Cut the caging material so that each piece fits in the spaces between the T-posts, forming a square box.

The outer caging should be installed about one or two feet above the top of the container—to allow easy access for regular maintenance such as pruning or watering—and reach the top of the T-posts.

Secure the outer caging tightly to the T-posts in several different spots. Much like the horizontal trellising, the outer portion of the support system should be in place before the branches reach this point so they can easily grow into the caging’s holes.

A lot of hard work and preparation goes into the cultivation of a successful cannabis crop. The best way to avoid failure is by taking the necessary steps to prevent unwanted occurrences in the garden.

A plant falling over from a strong gust of wind, or branches breaking from the sheer weight of ripening flowers is a disheartening way to lose a portion (or all) of a crop. Especially since this type of failure can be easily prevented.

Using this simple method of plant and container stabilization will help ensure that your plants will stay upright throughout the season and give you one less thing to worry about.

Right: Illustrated steps to support outdoor cannabis plants in large fabric containers. Source: Smart Pots


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Written by Kyle Ladenburger | Director of Regulatory Affairs for Age Old Organics & ENP Turf, Freelance Garden Writer

Profile Picture of Kyle Ladenburger
Kyle L. Ladenburger is a freelance garden writer who has worked in the gardening/hydroponics industry for over 15 years. As an avid indoor and outdoor gardener he is well versed in nearly all types of growing methods with an overall focus on sustainability and maintaining healthy soils. He holds a strong conviction that growing one’s own food is a powerful way to change our lives and our world for the better.

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