Grow Weed Easily And Successfully By Building A Greenhouse

Published :

Grow Weed Easily And Successfully By Building A Greenhouse

Building and growing in a greenhouse aren't as difficult as you might think. Read on to discover the benefits, and the ideal greenhouse setup for you!

A greenhouse provides the best attributes of both indoor and outdoor cannabis growing. But don’t think that building your own greenhouse means a difficult or expensive endeavour. A simple greenhouse doesn’t cost much, and all you need is a suitable space in your garden or on your balcony to get started growing cannabis like a pro. Read on to learn how to grow cannabis easily, and successfully, in your own greenhouse!


For many growers, a greenhouse is an easier and more practical option than an indoor grow room. It provides all the perks of outdoor cultivation, like natural sunlight, yet offers protection from the elements, insects, and animals.

For growers in cooler regions of the world, a greenhouse can also provide a longer growing season. You can, for example, plant your seeds earlier each season, as well as harvest later if need be—and you don’t need to worry as much about cold temperatures and rain. You also have the option to heat and cool your greenhouse, supporting ideal conditions for growing top-quality weed rivalling that of warm-weather growers.

Aside from offering protection from wind, rain, and frost, a greenhouse has a lot of other benefits. For example, you can equip your greenhouse with artificial lighting to take advantage of grow lamps and natural sunlight. This way, you can control a plant’s vegging and flowering phases as if you were growing indoors. Moreover, if you set up a small greenhouse on your balcony or terrace, it can be a good way to keep suspicious odours and noise from being an issue indoors.

Grow Cannabis in Greenhouse


You can grow all types of cannabis in a greenhouse with great success. Here are some specifics about autoflowers versus photoperiod plants:

• Growing autoflowering cannabis

Let’s start with autoflowering cannabis. The features that make autos popular among indoor cultivators are largely the same among greenhouse growers. This includes their compact size, fast growth, and, of course, their ability to flower based on age, rather than light cycle.

When it comes to size, autoflowers often max-out at a metre or less in height, with some cultivars reaching only 50cm. This makes them excellent candidates for smaller greenhouses, such as those on a balcony. Moreover, some greenhouse growers like that you can cram several autos into a relatively small space to increase yield.

The short life cycle of autoflowers is a key advantage to growers of all types. Taking 60–70 days from seed to harvest on average, this is extremely short in comparison to feminized photoperiod strains, which take this long just to flower. In a greenhouse, this feature allows growers to reap multiple harvests per year and per season.

In terms of light cycle, autoflowers allow growers to plant at basically any time of year, as long as there is enough artificial light to support robust growth.

• Growing feminized (photoperiod) cannabis

When growing feminized photoperiod strains, you have the choice to use exclusively natural sunlight, or you can supplement with artificial light. If you grow in natural sunlight only, your plants will essentially have to follow the regular outdoor grow season schedule. At the end of summer, plants will start to flower, and then you can harvest sometime in autumn. Luckily, the controlled conditions of a greenhouse can support flowering deeper into fall, which is a major benefit for sativa growers especially.

By supplementing your grow with artificial lighting, however, you no longer need to follow the outdoor grow season if you choose. Instead, you can calculate an ideal sunlight/grow-light schedule to capitalise on the free power of the sun, while benefiting from the control offered by grow lights.


Given ideal environmental conditions are met, your plants can, in principle, grow just as large in a greenhouse as they can outdoors. It’s not uncommon for cultivators to harvest 2–3m-tall monsters, or even taller. Of course, this all depends on how much space you have in your greenhouse and how large of a plant you want to deal with. Even if you don’t have a super tall space, you can still potentially grow sativas and other lanky strains using training techniques. Simple LST can keep vertical growth in check, and techniques like topping can help to boost yield while breaking apical dominance. You can also keep height in check by skipping the vegetative phase and initiating flowering right away.


You can build and purchase greenhouses of virtually all sizes, from simple mini-greenhouses to custom-built, full-fledged extensions for your home. You can find greenhouses consisting of a transparent PVC sheet over a metal or wooden frame, some that use polycarbonate plastic panels, and others made from glass. Some types of greenhouses are designed to be situated against a wall of your home so the heat keeps the greenhouse warm.

A simple walk-in greenhouse with a metal frame and a sturdy PVC sheet with a zipper door can be purchased for little money. These are great if you’re on a budget and/or you don’t want to go all out building a greenhouse from scratch.


Where you place your greenhouse is very important, for a number of reasons:

Natural Sunlight• Natural sunlight

The location of your greenhouse will ultimately determine how much sun your plants receive. Obviously, you don’t want to place your greenhouse behind your house in the northern part of your garden where your plants never get any sun. The best location is the south or southeast side of your house.

Shaded Area• Shaded area

On the other hand, if you live in a hot and sunny climate like the Mediterranean, you may want your greenhouse in a shaded location. Likewise, if you plan to mostly use artificial lighting, it matters less where you greenhouse is located in relation to the sun.

Electricity• Electricity

However, you will want a power outlet nearby if you plan to equip your greenhouse with grow lights, fans, and/or an exhaust system.

Shelter from wind and rain• Shelter from wind and rain

You want a location for your greenhouse that isn’t exposed to strong wind and weather. A sheltered area behind your house, or somewhere tucked away on your terrace or balcony, can be optimal. If you plan to build a greenhouse in a less sheltered place, like in the middle of your garden, this will need to be professionally constructed and anchored in place. Otherwise, a strong gust of wind could be enough to blow your greenhouse away.

Water and drainage• Water and drainage

Another important consideration: Is a water connection and drainage nearby? You don’t want to be lugging buckets of water to your plants or draining the runoff into the middle of your garden. Having water and drainage available is also important if at some point you decide to automate your system or implement hydroponics. Some hydroponic systems may require changing the tank every few weeks. If your greenhouse is on your balcony and there is no way to empty or fill the tank, short of carrying the tank into your house bathroom, this could be an issue.


Supplemental grow lights aren’t just good for greenhouse growers in regions without much sun; they can be beneficial for growers in any location. Even in sunny climates, an additional grow light can get your plants through the cloudy days. Plus, if you live somewhere with a chilly climate, a powerful HPS light can support adequate temperatures for your plants.

Another big benefit of having a grow light in your greenhouse is that you can extend the hours of light your plants receive. For example, you can use the lights to provide your vegging photoperiod plants with 18–20 hours of light, even when natural daylight hours would be much shorter. This allows you to grow your plants all year long—plus it will greatly increase your yield.


In addition to artificial light, you can also install a darkening system in your greenhouse. Such systems usually consist of automated blinds or a curtain on a timer, and allow you to induce and support flowering even when the days are long and sunny. With a darkening system, you are able to simulate the shorter days in fall. Put your plants under a 12 hours on, 12 hours off light cycle to initiate flowering. Pro greenhouse growers time their light-dark cycles so they can plant and harvest cannabis all year long!


At times, a greenhouse may also bring with it some issues. One of them is the potential for the space to get extremely hot and humid, and this can happen quite quickly depending on the climate and positioning of the structure.

When the sun is shining into your greenhouse, temperatures can rise to dangerous levels for your plants. In some cases, this may only cause plants to grow slower, but once temperatures exceed 40ºC, fatalities can occur.

As such, you want to make sure that your greenhouse has optimal ventilation and cooling, and you may want to consider artificial lighting with less heat output, like LEDs.

If you build a simple PVC greenhouse, you can make it so the windows open during the sunny months. If the greenhouse doesn’t have openings, you can easily cut the plastic sheeting to provide some nice airflow. More elaborate greenhouses can be made with windows that open and close, and some are even automated.

Aside from rain, humidity is rarely an issue outdoors as there will always be a nice breeze. But in a greenhouse, excessive humidity can quickly lead to an unhealthy growing environment that facilitates mould and bud rot.

To keep your plants happy, make sure there is good air circulation in your greenhouse. Some of the above methods for temperature control will also help keep humidity in check. You could also leave the greenhouse door open for periods of time, and again, can cut holes into the sheeting where necessary.

Likewise, a simple oscillating stand fan gently blowing air across your plants can prevent pockets of stagnant, humid air from forming. You should also keep a thermometer and hygrometer in your greenhouse. Just keep an eye on these things and your cannabis will thrive!

Airflow inside a Greenhouse


Do you desire the yield and majesty of outdoor cannabis, and the control and safety offered by indoor grows? Consider a greenhouse. Using a variety of different materials and building methods, you can customise a greenhouse to suit your needs and budget. You can build out a 220cm x 120cm walk-in greenhouse with a sturdy PVC cover over a metal frame for under €100. And once you’ve harvested your first crop of greenhouse cannabis, you can always upgrade to something more elaborate to push your plants’ potential even further.