How to Build a Homemade Greenhouse for Cannabis

There are many reasons why you may want to consider setting up a homemade greenhouse for weed. Perhaps you have space constraints or, your last batch of outdoor cannabis didn’t make it because winter came a bit too early.

Setting up your greenhouse doesn’t need to be a complicated or expensive endeavor. 

Familiarity with some DIY principles and an adequate amount of research will go a long way in setting up your small cannabis greenhouse at a minimal premium. 

We’ll look at what you need to buy as well as how to build a marijuana greenhouse.

How does a homemade greenhouse for weed work?

While cannabis is a hardy plant, and there are specific strains that fare pretty well outdoors, you may have grown accustomed to your favorite and might want to start growing marijuana in your greenhouse. 

A homemade greenhouse for weed enables you to produce nearly any strain all year round. An enclosure that creates a controlled environment for your cannabis plants to thrive in, greenhouses have been used to great agricultural success for more than 200 years. 

By keeping tabs on the light, water, and nutrients, you increase your plants’ potential to yield some fat buds by your next harvest.

How much does it cost to build a greenhouse?

The beauty of building your outdoor cannabis greenhouse lies in how easy it is to scale your project according to your time and budget. You could get away with some PVC pipes, a few meters of plastic sheeting, and some DIY skill for around $50. 

You may also opt for one of the many (admittedly costlier) self-assembly kits available online. From $100 up to a few thousand dollars in price for premium models, these eliminate much of the guesswork that accompanies many new DIY outdoor greenhouse projects.

Is it possible to build a DIY cheap greenhouse?

After a quick trip to the hardware store and a stop by your local nursery, you could very well walk away with all you need to set up your cheap DIY greenhouse. 

As with any new project, you should begin with your budget, followed by your list of materials. By scaling the size and items used, you may be surprised at how cost-effective a greenhouse can be. 

Main homemade greenhouse for cannabis designs

While it’s acceptable to base your decisions on budget alone, you’ll also need to consider your chosen design’s functionality. 

There are three good basic templates for what makes well-priced and easy greenhouses.

Hoophouse

As the name suggests, this design consists of hoops secured to the ground and then covered in a layer or two of plastic. They represent a very cheap greenhouse construction method through the minimal use of materials and ease of assembly.

Tunnel

Tunnels follow the basic design of hoop houses but generally tend to be longer with higher clearance, making them easier to work in. If you’re aiming at producing larger crops and have the space available, a tunnel may be the plan for you.

Gable

Gables are great small cannabis greenhouse designs to go for if you experience some soft snow and rain with little wind in your location. 

The raised center roofline also creates a greater surface area for the sun to heat during the day, making them an excellent choice for colder climates.

What do you need to make a cheap DIY greenhouse?

Depending on your choice of materials, assembly of your cheap DIY outdoor greenhouse could be a straightforward affair. 

Let’s take a look at some of the basics you should consider before undertaking this task.

Toolkit: 

When building a cheap greenhouse from scratch, there are a few essential tools you’ll need on hand to make the task easier, listed in order of importance. 

While you may get away with hand tools, if you’re undertaking a larger project, you should consider employing the aid of power tools in many of these cases.

• Measuring tape: There’s no getting around the need to make sure things are square and accurately sized, so this is a minimum requirement.
• A hammer or screwdriver: While it’s arguably much easier and faster to hammer in nails everywhere, some designs might call for the additional rigidity you get from using screw fasteners.
• Saw: depending on the design you chose, you may be able to avoid having to do any sawing by having your local hardware store pre-cut the materials for you.
• Staple gun: will allow you to fix the plastic or tarp to your frame quickly.
• Good quality scissors: You’ll need these to cut your plastic, tarp, and string or cable ties.

Frame

All of the cheap DIY cannabis greenhouse designs we’ve mentioned require a framework, which gets covered in plastic or tarp. Your frame needs to be sturdy enough to bear the weight of the covering and protection from natural forces like rain, wind, or even snow.

Plastic

A plastic frame may prove to be the cheapest option, and most PVC tubes are very easy to cut through with even a basic hacksaw. They bend easily and will allow you to quickly get the shape you’re after for your DIY cannabis greenhouse.

Once cut, they’re immediately ready for use and aren’t susceptible to damage from humidity or pests. Something you should bear in mind - some plastics may become brittle from UV exposure over a matter of years.

Wood

When secured with the correct fasteners, a wooden frame may prove to be a very sturdy structure in windy, rainy, and snowy conditions. Even for an easy greenhouse build, adverse weather should be a consideration. 

Depending on the dimensions of the timber, you may want to have it pre-cut by your supplier. Alternatively, if you own a cut-off saw, the task remains straightforward.

Wood frames generally weigh more than their plastic counterparts, meaning that assembly may take a bit more time. Your labor gets rewarded with a structure that could stand for many years with some routine maintenance.

You’ll need to be sure you treat your wood to prevent sun and water damage. A good coat of varnish is an extra step required to avoid the ingress of weather, as well as pests. Your outdoor cannabis greenhouse will serve you that much longer if you look after the frame.

Plastic Sheet or Tarpaulin

Once your frame is up, you’ll need to cover it in plastic sheeting or tarp. When choosing your greenhouse covering, you should consider your weather conditions and, particularly, how long you’d like this to last. Good quality polythene can last for more than ten years where the cheapest products may start deteriorating after less than three years.

How to build a homemade greenhouse for weed

Now that you have an idea of the options and requirements for building an easy greenhouse, let’s look at the steps that stand between you and your very first harvest.

Choose Your Outdoor Space 

Cannabis loves the sun’s rays, particularly in the early morning. For this reason, you should choose your space with this taken into consideration. 

Marijuana grows best when provided with at least 7 hours of direct sunlight per day. 

A south-facing area should be perfect for this but, you may need to factor in practical limitations, like water and power supply. You may also need to consider your neighbors and other prying eyes. Perhaps a stealth outdoor grow setup would work best for you.

Prepare Your Build Site

Begin by clearing the ground of any large debris and making sure that the surface is at least reasonably level and the soil nice and compact. 

Laying down a ground cover should be considered, especially if you plan on growing through colder months. A tarp will also prevent unwanted weeds and pests from getting to your crop.

Construct the Frame

Assembling a cannabis hoop house is reasonably straightforward; begin by fastening your bottom frame, bend your PVC pipes into place and fix them to it with u-clips. 

You’ll also want to create lateral stability by adding a few cross members to keep the hoops equally spaced from each other.

Add a Door

Your point of entry could be something as simple as some netting, fastened with velcro to a fully-framed door. If you’re working with a timber greenhouse and may face adverse weather, a sturdy door is necessary.

Cover the Structure With Tarp

Now that your easy greenhouse is taking shape, drape your tarp or polythene plastic over the structure and fasten it. Make sure to pull it taught as required as wrinkles will diffuse more sunlight than necessary. 

You may opt to use staples to secure it in strategic places but avoid puncturing the material unnecessarily.

Add Your Plants

As soon as you’ve secured your covering, you can start moving in the plants. Whether you’re growing from seedlings, clones or just re-locating your indoor grow, you’ve just taken the next big step towards successfully growing cannabis.

Save money by building your own greenhouse cheaply

While many companies offer small cannabis greenhouse solutions at price points ranging from fair to fairly ridiculous, you can save a ton of money by setting up your greenhouse from scratch. 

Keep in mind that these organizations make their money off other peoples’ unwillingness or inability to build their greenhouses themselves.

With that in mind, do your reading about the subject, draw up some basic plans, and prepare a budget well before you start building. 

If you organize it correctly and you don’t mind getting your hands a bit dirty, building your homemade greenhouse for weed could be a rewarding experience in more ways than one. Pick your favorite greenhouse strain and happy growing!

About the author: Parker Curtis

Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.