How to Build the Best Indoor Greenhouses for Growing Marijuana

Best Indoor Greenhouses for Growing Marijuana

When it comes to growing marijuana, there are growers who prefer growing small amounts and then there are those who prefer to grow large amounts of weed. However, there are also some growers who would prefer to grow very large amounts of weed and for them, an indoor growing setup is just not enough. The best option that these guys have is to set up a greenhouse – which is somewhat of a mix between an indoors and an outdoor growing setup. Over the course of this article, we take a closer look at how to build the best greenhouses for growing marijuana.

We begin by understanding the difference between growing indoors vs growing outdoors vs growing in a greenhouse. This is followed by the main question straight up ahead – how to build the best greenhouse for growing your weed! Without further ado, let us take a closer look:

Growing Indoors vs Growing Outdoors vs Growing Marijuana in a Greenhouse

You can grow weed in broadly two ways: indoors and outdoors. However, when you grow your weed outdoors, that is by planting the seeds in the soil and under the open skies, you have very limited control over it. 

Basically, in an outdoor growing setup, you are leaving your marijuana much to the mercy of the forces of nature. Under this setup, your cannabis plants will grow based on the amount of light and heat they get from the sun and if the sun doesn’t shine for a considerable period of time owing to clouds, fog or the season, you are going to be in quite a lot of trouble. Similarly, a high volume of rain or snowfall can also damage your plants. When you grow your weed outdoors, you are also putting it at a major risk of getting damaged by insects and pests or even by wandering animals. Furthermore, there’s also the social stigma of people seeing that you are growing marijuana. Despite the legal status across many states, it is still largely a social taboo.

This is where growing your weed indoors comes in. In an indoors growing setup, you can grow your marijuana inside a room or inside a grow cabinet or a grow tent. That gives you two huge benefits: first, all the factors of nature have to be replicated and are thus completely under your control, allowing you to simulate the perfect and ideal conditions for the growth of your weed. Secondly, it remains safe from insects, pests and even from nosy neighbours! You get a higher control because here you use grow lights that replace the sun by providing light and heat, you can provide water and ventilation by yourself and you can also provide the required nutrients mixed in the soil and water. 

These are the two most common ways of growing weed. However, of late, those who want to grow very large quantities of marijuana have begun preferring greenhouses, which is basically a mix between the indoors and the outdoor growing setup. Here, you are basically growing your weed in a setup which is covered from all sides but it is not inside a room, it is located outdoors! Let us take a closer look at understanding how greenhouses work for growing marijuana and what the benefits of growing your weed in a greenhouse are.

Benefits of Growing Cannabis in a Greenhouse

A greenhouse basically has transparent walls which allows the solar radiation of the sun to pass through them. However, the biggest benefit that a greenhouse gives you is that it traps this light and the resulting heat inside it and ensures that the setup remains warm even if the temperature outside is a little cold. The sunlight basically helps keeping the soil and the plants warm and that warmth is sustained inside a greenhouse. Furthermore, the infrared radiation that is released from the soil and the plants is also trapped inside the greenhouse, keeping it even more warm. This trapping of the sun’s energy is basically what the ‘greenhouse effect’ is all about.

The best greenhouses for growing marijuana come with supplemental lighting setups which ensure that the plants get light for extended hours even after the sunlight hours are over. This is because marijuana’s plant cycle requires about 18 hours of light during the early stages and about 12 hours of light during the flowering stages. Basically, instead of using grow lights all the times like you do in an indoor setup, you can use a combination of sunlight plus grow lights giving the plant the best possible light and heat it needs to grow – a combination of natural light and artificial light.

Greenhouses are also great for providing the perfect climate to your plants. If the heat inside the greenhouse increases too much, you can perhaps open up a panel or two on the top which allow the excess heat to dissipate. You can also use a ventilation system along with a duct fan to ensure air is circulated well and heat levels remain controlled. Moreover, since it is a closed setup, it allows you to trap and retain the heat if you are in a cold climate. Some users also tend to use an air conditioner inside a greenhouse to ensure that the temperature does not get too hot.

Given that the best greenhouses for growing marijuana are usually a closed setup which have no space for a leak, it protects your crops from excessive rainfall and the humid environment it leaves later. You can use a combination of humidifiers and dehumidifiers placed inside the greenhouse so that the humidity levels are maintained. Let us now take a closer look at how to build the best greenhouses for growing marijuana in 2020.

How to Build the Best Indoor Greenhouses for Growing Marijuana

Now that you know what a greenhouse is and how it affects the growth of marijuana and why it is beneficial, let us take a closer look at how to build the best greenhouses for growing marijuana. These are the things that you need to keep in mind when you are building your own greenhouse for growing weed.

  • Preparing a Blueprint

This is the most important step. Before you build anything you need to have a blueprint ready with you. This is basically about how big the greenhouse is going to be, the number of plants that will be inside it and does it have enough space to keep the plants and the equipment needed to grow the plants. Moreover you also need to consider the height of the greenhouse and see if there is indeed enough space to attach grow lights and if there is appropriate distance between the lights and the plants. You also need to account for the height of the plants and how you are going to grow them. There should also be adequate space for you to walk around. This all has to be plotted down on a paper before you begin building your greenhouse for growing marjiuana.

  • Setting up the Basics

Once you have set up the blueprint, you need to begin setting up the framework of the greenhouse upon which layers and coverings will then have to be added. This needs to be carried out as per the length and the breadth that you have figured out based on the blueprint. You should also know by now how many grow lights, humidifiers and other equipments will you be needing. You can set up the basic framework of the greenhouse now. You have to decide whether you want to use a wooden framework or a metal framework for setting up the frames which will carry the covering. Another factor that you need to keep in mind is that there are no trees near your greenhouse because the shade of the trees might block the light from entering the greenhouse where your marijuana is growing.

  • Covering the Greenhouse

The covering of the greenhouse is one of the most important aspects when it comes to how to build the best greenhouses for growing marijuana. This needs to be done carefully and the material needs to be the best because the covering of the greenhouse is its most important aspect because this is what determines the heat that gets in and gets trapped inside. You will need to decide which material you want to buy – are you going to by glass, which is heavier and costlier, or are you going to buy fiberglass or plastic? A coat of resin has to be given to the material that you choose to finally install to cover your greenhouse. There are also some types of paints that block the outside view of what’s growing in your greenhouse. 

  • Providing Ventilation

Ventilation is critical for your marijuana plants to grow and you can choose to provide either vents which have inline duct fans attached on to them, or you can additionally choose to have openings on the top of the greenhouse which can open up like windows to dissipate any excess heat that might get accumulated in the summer months or months of excessive heat and humidity. You need to figure out which types of openings do you want and where exactly should they be located. Another thing that the growers need to know is the type of fan that they want and the location where they are going to install it. Ventilation is an important part of your greenhouse! Humidifiers, dehumidifiers, carbon filters and air conditioners also need to be purchased so that the air quality remains perfect for growth.

  • Setting up Grow Lights

While the whole point of a greenhouse setting is to use and to maximize the incoming light and heat of the sun, growers also need to ensure that in case of months where there is no light or limited light, their plants get sufficient light and warmth from artificial sources, which are the grow lights. Growers need to decide on the kind of grow light that they are going to buy, how high they are going to hang it and where exactly are they going to hang it so that their plants get the maximum possible benefit out of them. Especially during the vegetative stage of growth, marijuana plants require up to 18 hours of light and those who plan to build the best greenhouses for growing marijuana need to consider the grow lights and their requirement in detail.

  • Setting up Water Resources

Water resources such as a barrel of water and a pump with a tube and a nozzle also need to be set up so that you can easily water your plants. You can also mix nutrients in the water and spray on to the plants – this is an aspect which is quite similar to that of an indoor setup. 


We hope that this article helped you understand what a greenhouse is and how growing marijuana in a greenhouse differs from growing it in a traditional outdoors or an indoors setup. The best greenhouses for growing marijuana are the perfect cross between indoors and outdoors growth and allow you to grow your plants under ideal conditions and give you a good output. This is particularly a good technique to grow weed for those growers who want to grow large quantities of cannabis. Now that you are at the end of this article, we hope you make a more informed choice when it comes to building the best greenhouses for growing marijuana! 

Happy Growing 🙂



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