Learning how to build a greenhouse can be a fun project that allows you to create the perfect space for growing your garden. By learning how to build a greenhouse yourself, you’ll be able to customize the structure to your exact needs and make it as big or little of a project as you want.
When thinking about how to build a greenhouse, there are a variety of techniques, shapes, and sizes available to you. Wood and PVC are the most readily available materials, easily accessible at any major home improvement store. They are both easily worked and can be made to your specific needs.
In this post, we’ll focus on a traditional house style made out of wood and a PVC hoop house. We’ll discuss construction basics, understanding the materials you need, and the steps for building a greenhouse by yourself.
Before You Start: Construction Basics
There are some general rules of thumb that you’ll need to know before you start building a greenhouse. It’s important to use these rules to ensure your project comes out the way you want, and we’ll reference them throughout the project.
Measure Twice, Cut Once
One of any construction project’s most widely circulated rules is to measure twice and cut once.
When building a greenhouse, you’ll be cutting materials, no matter if it’s wood or PVC. If you cut too much, you’ll have wasted the materials; if you cut too little, your structure won’t fit together.
Always measure twice, and cut once when building a greenhouse.
Check To Make Sure You’re Level
Whether you’re building a greenhouse on flat ground or a slope, you’ll need to ensure it’s level throughout the process. When buying tools and materials, make sure you purchase a box level to check that each piece of material you attach is level.
To simplify it, you can use an electronic level that removes all human error. When building a greenhouse, making everything level matters when you water and pot plants – you don’t want to constantly shim your plants up and have all the water run to one side.
Make Sure You Can Reach the Roof
While it may seem basic, ensuring you can reach the roof is important. You must wrap the entire structure in a greenhouse plastic material when building a greenhouse. If you can’t easily reach the roof, you won’t get a good seal, water or snow will drip in, and heat will escape.
Buy Enough Materials
A good rule of thumb when building a greenhouse, or any structure, is to figure out how much material you need and purchase 10% more. This ensures that any missed cuts or issues you didn’t plant for can be easily addressed. Excess materials can also be used for shelving or other accessories when you’re finished.
How to Build a Greenhouse
When thinking about how to build a greenhouse, the first thing to consider is what materials to use, which correlates to the size and type of greenhouse you want. A “house” style with a pitched roof is generally made with wood, whereas a ground-level “hoop” style is made with wood and PVC.
A wooden greenhouse will generally be more attractive and allow for shelves and more space to move around. Wood greenhouses, however, are more difficult to build and require more tools and time, making them a challenge for beginners.
A PVC greenhouse is easy to build and sits right on the ground, making it easy to reach everything and assemble. The PVC, however, isn’t very attractive and doesn’t have the same customization ability as a wood one.
Both styles are great for DIY greenhouses, and you need to determine which works best for your situation. You can start creating your materials list once you decide which material to build a greenhouse with.
Wooden Frame Greenhouse
The below is the materials list for an 8x8x8 greenhouse, but remember to add extra materials when ordering:
- Cordless drill
- Compound miter saw
- Tape measure
- 2 x 4 x 8 – 24 pieces
- 1 x 3 x 8 – 5 pieces
- Door hinges – 2
- Door handle – 1
- Philips head screws – 2lbs
- Greenhouse plastic – at least 50 feet
- Staples – 1 box
Step 1: Gather Your Tools and Supplies
When building a greenhouse out of wood, you want to use 2x4x8 lumber primarily. This is readily available and easy to work with. You’ll also need several tools. One of the most important ones is a saw, and we suggest a compound miter saw to allow you to cut angles for a sloped roof and make quick work of any other cuts.
You will also need a power drill. To go with the grill, you will want fasteners – your best bet is 2-inch Philips head screws (at least 2 lbs) and a drill bit that matches the size of the screws.
When ordering wood for building a greenhouse, measure the space you plan on taking up. For this post, we’ll say an 8x8x8 greenhouse below the roof. To calculate the wood required, you need to understand how you will build the structure.
Step 2: Build The Walls
Building a greenhouse wall can be as easy as screwing together a box with one horizontal support beam. Using the 8x8x8 dimensions, you won’t have to cut any of your 2x4x8s.
Each wall will require a top and bottom piece, two side pieces, and one horizontal middle support beam to make it more rigid. This means that each wall will take five 2x4x8s.
That covers the three walls without a door, but you’ll need to access your greenhouse.
To frame a door, first figure out how wide you want it to be. Most standard doors are 36 inches, but you can use whatever size fits you and your garden cart.
Step 3: Build the Door Frame
An easy way to frame a door is to build a wall without a horizontal middle support beam and put in a vertical stud. You can frame a door using 1×3 strapping wood framed in a rectangle with a middle support beam.
Attach it to your stud with hinges and put a handle on it.
Step 4: The Roof
Once you have completed the door and walls, it’s time to move to the roof. This will be the hardest part of the build so far.
You need to cut 45-degree angles into your 2x4s to make a pitched roof angle and attach them to the top of your walls. Generally, you can use two of these in the front to form a triangle and another two in the back.
Once you have attached your angle roof beams, you can also attach horizontal mid-support beams to increase the rigidity of the greenhouse.
You’ve just finished the wood part of building a greenhouse!
Step 5: Wrap It Up
The last step is wrapping the greenhouse in plastic film to trap in UV rays. You can buy greenhouse plastic online (like the Farm Plastic Supply – Clear Greenhouse Plastic Sheeting in the materials list).
Attaching your greenhouse plastic is best done by wrapping it under the bottom 2x4x8 and stapling it to the 2×4. This means that the greenhouse plastic goes from under the structure around the top and back to the other side. The structure’s weight will help hold it in place and ensure it doesn’t rip.
When attaching greenhouse plastic, you want to be sure there are no gaps. You may want to double-wrap your greenhouse to prevent water from coming in.
PVC Hoop House
When thinking about how to build a greenhouse, make sure to take on a project at your level of comfort. Try the PVC hoop house if the wood greenhouse described above seems too difficult. This structure will be much less complicated.
- Cordless drill
- Tape measure
- 2 x 4 x 10 – 3
- PVC Pipes .5in x 12 feet – 6
- 1 x 3 x 10 – 2
- Philips Head Screws – 1lb
Step 1: The Ground Frame
To build a greenhouse out of PVC, you will want to start by building your ground frame. We’re using the dimensions of 10 x 5. Take two 2x4x10s as your long sides, and cut one in half to make short sides – you will now have wood to make a rectangle once screwed together.
Step 2: Add the Hoops
This ground frame can be laid down, and you are ready to start attaching your hoops. Screw a piece of PVC into the wood frame and bend it across the frame to the other side, where you can screw it in again; this will form a hoop. You will want to start at one end and move your way down.
Repeat this process at even intervals until you have used all the PVC. Add a piece of 1×3 strapping to the top of the hoops to add rigidity to the greenhouse. You can also use a 1×3, cut in half, to add vertical support beams. Your greenhouse structure is now ready for plastic!
Step 3: Wrap it Up
Like the wood structure above, wrap from one long side to the other, ensuring the plastic goes under the structure and wraps around a 2×4. Staple the plastic down, and allow the weight to hold the plastic in place as you wrap. You’ll need shorter pieces for the front and back sides and one large piece for the long sides.
Wrapping twice is a good idea here too.
Step 4: Add an Entrance
You’ll need to access the hoop house, which you can do using a zipper opening to attach an access point.
Ready for Building a Greenhouse?
When deciding how to build a greenhouse, you have many options in terms of shape, size, and material. The easiest ways to build one are with wood or PVC in a house or hoop structure. A DIY greenhouse project can be fun and rewarding and doesn’t require complicated tools or building techniques.
While a wooden frame greenhouse is more time-consuming and complex to build, it makes a nicer-looking structure with more room and a sturdier frame. In contrast, PVC is easy to work with and takes much less time, but it’s not as attractive, is ground level, and is less sturdy than wood.
Once you finish your greenhouse, check out our guide on Garden Tools to make sure you have everything you need to care for your plants!