Cannabis How-Tos

How to Grow Cannabis: A Beginner’s Guide

Calling all green thumbs: Ontarians can grow up to four cannabis plants at home. These beginner tips can help you get growing.

How to Grow Cannabis

Interested in growing cannabis at home? Ontarians age 19 and over can legally grow up to four cannabis plants per home (not per person) for personal use.

Whether you plan on growing indoors or outdoors, from seeds or from clones, there’s a lot to consider. Here are some beginner-friendly tips for each stage of the growing process.


From germination to seedling

To grow cannabis at home, you have two choices: grow from seed or start from a clone (a cutting taken from an active mother plant). Whichever you opt for, you’ll want to carefully consider the cultivar’s growing traits and environmental needs. Some genetics are more adaptive to cooler climates, while others are better suited for hot and humid environments. Some stretch tall while others stay short.


There are three categories of cannabis seeds: regular, feminized and autoflowering (here’s a close look at the differences between them). You can legally buy seeds from the OCS and Authorized Retail Stores.


Before you can plant your seeds, you’ll need to germinate them. Germination (or “popping”) is when the plant begins to sprout from the seed, prompted by a combination of water, heat and air. Simply place the seeds a few centimetres apart between a few sheets of paper towel soaked in distilled water. Sandwich the whole packet between two plates (creating a dark, warm dome) and keep it at approximately 21ºC until the seeds split and a tiny sprout appears. Mist the paper towels as needed to keep them moist.

Check the seeds every day for the development of taproots — the primary root of a plant’s root system. Taproots usually appear after two or three days (although it can take up to seven). If it takes any longer, your seed may be a dud.


Once you see taproots, transfer the seeds to a small container with a growing medium, such as soil or peat, and drainage holes, to avoid mould or rot. Each seed should have its own container. Your seeds are now in the seedling phase, so they’ll need a warm, relatively humid environment with about 18 hours of light per day. They’ll need to be watered every three to seven days (or when the first five centimetres of soil feel dry).

Over two to three weeks, the seedlings will grow vertically and sprout multiple sets of characteristic serrated leaves (here’s a closer look at the components of a cannabis plant), and their roots may begin to poke out of the container’s drainage holes. These are signs that it’s time to transplant your seedlings to a larger pot or to your backyard.

Growing from clones

A cannabis clone does not require germination, but it does need time to sprout roots (if it hasn’t already) before it’s ready to be transplanted. The OCS and Authorized Retailers do not sell clones.


From transplanting to vegetating

Once your seedling (or clone) is ready to be transplanted, what happens next depends on whether you’re growing indoors or outdoors. Either way, this phase is called the vegetative stage. Wherever you’re growing, remember to keep kids and pets away from the plants.


Your seedling will need to be transplanted into a container with drainage holes and at least twice the volume of the original container. Keep in mind that you may need to transplant one more time during the growing cycle to give the plant enough room (a bigger pot allows for a bigger plant). Knowing the expected height of the cultivar can help you plan accordingly. Your container should be filled with soil (or other growing medium) that offers good drainage. Cannabis plants need about eight litres of soil for every 30 centimetres of growth.


Cannabis plants require a lot of attention and very specific conditions to thrive. To grow indoors, you’ll need an enclosed, clean and dust-free space where you can control the light and humidity (such as a growing tent). On average, plants require 18 hours of light each day during the vegetative phase. They’ll also need temperatures between 22°C and 26°C, relative humidity between 40% and 60%, fertilization and filtered water (every two to four days, or whenever the first five centimetres of soil feel dry).

Male or female?

Cannabis plants are “dioecious,” meaning they grow up to be either male or female. Only female plants produce the terpene-rich consumable buds, but to keep them from being pollinated and then producing seeds (which will ruin your harvest), you’ll need to remove every male plant from the area — even one male can pollinate and spoil the bunch. Male plants develop pollen sacks on their nodes (where the branches connect to the plant’s main stem), while female plants develop pistils (white hairs emerging from a tiny bract). You can differentiate male and female plants when they start to transition from the vegetative stage to the flowering stage.


You have two options for transplanting your seedlings outdoors: either into pots (as described above) or directly into soil. Pots allow for greater control over the soil quality and can be moved to suit sunlight and other environmental factors but also require more maintenance. Planting directly in the ground allows the roots to expand and benefit from natural microbes but takes away environmental control.


Cannabis plants are annuals, and because they are not indigenous to our region, outdoor growing can be a challenge. Timing your transplant is important; you’ll want to plant seedlings outside in mid- to late spring to take advantage of the longest possible growing season. You’ll also have to pick your spot wisely, taking these factors into consideration:

Although cannabis plants are adaptive to different weather conditions, they are susceptible to extreme temperatures. Cannabis plants shouldn’t be grown in temperatures below 12°C or anything above 30°C for sustained periods of time.

Cannabis plants need plenty of sunlight. When picking a location, consider that the plant requires a minimum of six hours each of direct and indirect sunlight. Try to keep plants away from artificial light sources that turn on during the night (such as garden or security lighting), as they can trick plants into thinking it’s daytime.

Choose a location that allows you to easily shelter your plant from temperamental weather, such as strong winds or rain. Or consider growing in a pot, which can be moved indoors if the weather take a turn.

Rainwater can help with an outdoor plant’s water needs, but you’ll need to monitor the soil and provide water as needed. Only use filtered water, and make sure the first five centimetres of soil are dry before you water again. Like indoor plants, outdoor plants can also be fertilized.


From flowering to harvesting

The time it takes a cannabis plant to flower — or grow buds — depends on a variety of factors, including the cultivar and environment. Indica cultivars tend to have shorter flowering times, while sativas usually take longer. Plants grown from autoflowering seeds may only take about 10 weeks to flower after germination, but otherwise, a cannabis plant will generally begin to flower eight to 12 weeks after germination.


If you’re growing indoors, you’ll need to trigger flowering by adjusting the amount of light and darkness to 12 hours each. This is called changing the photoperiod. The plant will then begin producing buds over the next eight to 14 weeks (autoflowers will produce sooner, without a change in light exposure). If you’re growing outdoors, the photoperiod change happens naturally as summer transitions to fall; Mother Nature controls the flowering period.

When cannabis is ready to be harvested varies depending on the cultivar and whether the plant was grown indoors or outdoors. Looking at the buds’ trichomes (those resin-secreting, mushroom-shaped glands) under a digital microscope can help you decide whether it’s time. More than half of the buds’ trichomes should have turned from clear or cloudy to milky white and/or amber.


If you’re growing cannabis outdoors, harvest time will also be dictated by the season. A deep freeze or sustained low temperatures can severely damage plants, so you’ll have to weigh weather conditions and bud ripeness. Most outdoor cannabis harvests happen in early to mid-fall (often in October, also known as “Croptober”).


To harvest your plants, you’ll need shears and plastic gloves (to keep your hands from getting too sticky). You can cut the plant at its base and then cut the branches or simply cut the branches in sections. Remove damaged fan leaves as you go. Then, start cutting the branches into smaller stalks. You can remove the leaves at this time, or you can wait until after the drying period.

How the pros grow

Growing cannabis outdoors isn’t just for home growers. Many Licensed Producers still grow the old-fashioned way — under the sun, in the fresh air. Take a look at how a few such Producers have mastered the art of outdoor cannabis cultivation.


From drying to consumption

To dry your flower, you need a warm, dry, dark and well-ventilated location. The branches can be laid on a drying rack or clipped to a clothesline to hang upside down. Drying time can range between three and 10 days, depending on the environment and the density of the buds.


After your bud is dried and trimmed, it’s time for curing. This process allows the bud to further dry while breaking down chlorophyll and preserving terpenes and cannabinoids — all of which maximize flavour and aroma.


You can cure cannabis by placing the dried and trimmed bud into airtight jars and keeping them somewhere dark, cool and dry. You’ll then have to “burp” the containers — removing the lid for a minute or two — to release moisture. Burp daily during the first week of curing and every few days after that. It can take anywhere from two to eight weeks to cure cannabis, depending on the cultivar and your personal preference.

Once cured, your homegrown bud is ready to consume. As with any cannabis product, start low and go slow to avoid overconsumption.

Please note that although it’s legal in Ontario to grow up to four cannabis plants in your dwelling, readers of this article should review and comply with all applicable laws regarding the growth and possession of cannabis. The content in this article is provided for general information purposes only and does not constitute legal or professional advice.

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