How to Build a DIY Greenhouse

Best Of Hometalk
by Best Of Hometalk

A DIY greenhouse will extend the growing season of your garden by allowing you to start seeds earlier and keep plants producing later in the fall. Large or small, building a greenhouse doesn't have to break the bank.

How to Build a Greenhouse (Nancy L)

See post: Nancy L|Building a Greenhouse From Old Windows

If you're looking for simple DIY greenhouse plans or ideas to build one in your garden, check out these DIY greenhouse ideas. There are many different ways to build a DIY greenhouse. You can purchase a kit, build one from scratch with paid for plans or design your own and work with materials you already have laying around.

How does a greenhouse work?

A greenhouse traps the sun's energy inside and keeps the plants warm, even in winter. Sunlight shines in and warms the plants and air inside. The heat is trapped by the glass and can't escape. During the daylight hours, it gets warmer and warmer inside the greenhouse, and the trapped heat will help keep it warm at night as well.

Keep Compliant with Local Ordinances

Check with your city’s building department and make sure you’re allowed to build a greenhouse on your property. Greenhouses are typically considered outbuildings, so you may have to apply for a building permit. And if you live in a community with a homeowner’s association (HOA), you’ll have to get approval from the HOA, which might be difficult because many housing communities have a strict no-outbuildings covenant. If this is the case you will want to build a mini greenhouse or hoop house that is not against the rules.

Where should I place a greenhouse in my yard?

Before you build, find a location where the greenhouse will be getting at least 6 hours of direct sunlight per day during the winter. By orienting the greenhouse east to west, the largest side will get full southern sun exposure. If you don't have an area with enough sun, grow lights can be added to compensate.

How to Build a Hoop House Greenhouse 

Build Your Own Greenhouse (Daniela N)

See post: Daniela N|Winter Garden - Hoop House - Green House

A hoop house is one of the simplest types of greenhouses that you can build in your garden. Hoop house greenhouses are great for extending the growing season in cold climates, and they are much cheaper and easier to build than large, glass greenhouses.

Supplies for a Hoop House

  • 4 flexible PVC pipes
  • Clear heavy duty plastic sheet
  • Rocks

Instructions for a Hoop House 

  1. Stick the ends PVC pipes into the soil creating two arches over your garden area.
  2. Drape a large piece of heavy, clear plastic over the two arches.
  3. Use rocks to weigh down the plastic and keep everything in place. 
  4. Plant seeds, flowers or veggies underneath the hoop house.

You can make a hoop house in this style to fit any garden area in your yard by adjusting the length of the PVC pipes that you use.

Basic Wood Greenhouse

How to Build a Small Greenhouse (John)

See post: John|Cedar 4x4 Greenhouse

If you are comfortable with carpentry you may want to try your hand at a larger sized DIY greenhouse made out of wood and plastic. This type of greenhouse is a permanent structure that stays up all year round.

Supplies for a DIY Greenhouse

  • Pressure treated 4x4’s
  • Cedar
  • Polycarbonate plastic

Instructions for a DIY Greenhouse 

  1. Use 4 pressure treated 4x4s for the bottom plates of the frame. Connect them with half lap joints on the bottom of the frame.
  2. Erect 6ft tall walls out of more 4x4’s, make sure they are square and level. 
  3. Add the main roof frame.
  4. Add cedar trim pieces so the plastic can be attached. I used 1 x 6 cedar for the bottom section.
  5. Fill in the rest of the roof rafters then add the rest of the plastic.
  6. Add 2 roof vents at the top of the roof.
  7. Add a double door to the front.

What kind of plastic do you use to make a greenhouse?

The most durable greenhouse plastic is called polycarbonate plastic. It can last for up to a decade if cared for correctly. It will also maintain a lot of heat and humidity for year-round growing.

Geodesic Dome Greenhouse

Greenhouse Ideas (Bren Haas)

See post: Bren Haas|Control Your Garden in a Geodesic Dome

A fun twist on a traditional greenhouse that is rectangular shaped is a geodesic dome greenhouse. These greenhouses can be built with wood and plastic like the ones mentioned above except is comprised of a series of wood triangles connected into a giant dome. Plastic is then added in the spaces between the triangles to retain heat and keep the dome insulated. It’s a great space for growing all year long.

DIY Greenhouse from Recycled Windows

DIY Greenhouse (Barb Rosen)

See post: Barb Rosen|Repurposed Windows Greenhouse

Building a greenhouse from recycled materials such as windows is a popular DIY option. Many people have extra windows left over from a home renovation, so it’s an easy material to acquire for your greenhouse project. Make a wood frame for your greenhouse and then add the windows to the wood boards instead or plastic.

Supplies for DIY Greenhouse from Recycled Windows

  • Old windows
  • Wood
  • Concrete
  • Caulking
  • Paint

Instructions for DIY Greenhouse from Recycled Windows 

  1. Start collecting old windows. Lay them down and try to match both sides with the same size windows. 
  2. Once you have the windows, construct the frame for each of the four walls. Use 2x4s for the studs and 4x4s for the posts on the corner. 14” of the stud should be to be down inside the ground to support the weight.
  3. Put up the walls and brace them. Make sure everything is level.
  4. If you build the foundation and height of the greenhouse low you will not need to pour any concrete. 
  5. Use deck screws to secure the windows to the frames.
  6. Use rocks or stones for the floor. They are good for draining and storing heat.
  7. Use outdoor caulk to seal holes and cracks that may be between windows and then paint the wood. 
  8. Place seed starts or potted plants in the greenhouse.

Mini Greenhouse with Recycled Windows

Mini Greenhouse Ideas (Empress of Dirt - Melissa)

See post: Empress of Dirt - Melissa|Hand-Painted Mini Greenhouse From Salvaged Windows

An alternative to a large full sized greenhouse is to make a small greenhouse that can be used for starting seeds and small plants.

To make a mini greenhouse out of recycled windows simply follow the instructions for a largely sized greenhouse but make it smaller. You can make a mini greenhouse with as little as 6 windows.

Use a table for a base (or build your own) and make a wooden frame that sits on top of the table. Attach the windows to the frame and you have a cute mini greenhouse from just a few recycled windows.

Greenhouse Attached to a House

Building a Greenhouse (Adina Johnson @ Simply Country Life)

See post: Adina Johnson @ Simply Country Life|Small Greenhouse Made From Old Antique Windows

Another way to build a small greenhouse with windows is to make a small cold frame. This type of greenhouse is small and can either be attached to the side of your house or free standing in the garden. 

  1. Build a garden box out of wood with one side higher than the other. Many homeowners like to push the garden box against the side of your house that gets a lot of sun.
  2. Attach garden windows to the top of the garden box with a hinge so you can open it from one side. 
  3. Fill the garden box with dirt and add seed or plants inside.

The windows will let the sunshine through, but trap the heat so the garden below the glass will be insulated.

Building your own greenhouse no matter how big or small is a great way to extend the growing season and have access to homegrown fruits and veggies all year long. Whether you build a simple hoop house or a large DIY greenhouse there is a project for every budget and skill level. Try building a greenhouse this year for your best garden yet.

Have you built your own greenhouse before? Share your DIY projects with us in the comments.

Written for the Hometalk community by: Adrienne Carrie Hubbard | Crafty Little Gnome

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