How to Build a Greenhouse

Build a DIY greenhouse to keep your plants happy with a greenhouse kit

2-4 hours

A simple DIY greenhouse provides a convenient place for your plants to flourish in an ideal growing environment, right in your own backyard. 

When you build a greenhouse using a greenhouse kit, all of the pieces are conveniently provided for you. For this project, we used the Palram Snap & Grow Greenhouse Kit, but there are many kits available for other types of greenhouses, including those made of metal, wood and resin. Assembly instructions will vary by kit, so make sure to follow the manufacturer’s instructions carefully. 

Tip: Anytime you build something using a kit, take inventory before beginning your project and sort the parts. Unpack the kit and check the contents to make sure you have all the pieces listed in the manufacturer’s instructions. 

Safety: Have a friend help you assemble your greenhouse – many steps will require assistance lifting and holding parts steady.

What You Need

SELECT A LOCATION

Before you begin, pour a concrete slab or build a wooden foundation slightly larger than the greenhouse’s base will be upon completion. Use a level to check that it’s completely flat before building to ensure your shed is stable. If your foundation is concrete, allow to completely dry according to manufacturer’s instructions. 

The chosen site should have good sun exposure through the day, and the greenhouse should be positioned so that the longer sides of the finished greenhouse face east and west. This will maximize sun exposure during winter months.

1
Assemble the base and corner uprights
Assemble the base and corner uprights

The back wall features two longer base rails, while the front of the base frame side will have two smaller base pieces that are connected using a third middle piece that will serve as the threshold for the greenhouse door.

• Before starting assembly, decide which end of the greenhouse you want as the entrance.
• Separate out the pieces needed to construct the rectangular base and the four corner uprights.
• The corner uprights will have two smart lock connectors protruding out at the base, forming a 90-degree angle.
• Attach the side base pieces onto the connectors on the corner uprights, then connect the four corner assemblies using the middle base pieces.

Tip: Use a spray lubricant for snug-fitting connectors.

2
Attach the roof frame
Attach the roof frame

• Find the four shorter pieces with three smart lock connectors at one end and attach them to the tops of the corner uprights so the rails form what will be part of the top of the front and back walls.
• There will be connectors angling up at a 45-degree angle that will help tie the roof trusses together with the rest of the frame.
• The front and back roof trusses connect at the peak and can be lifted into position with an assistant and placed onto the diagonal connectors.
• Assemble the three piece ridge beam according to manufacturer’s instructions. Snap both ends into the connectors at the top of the front and back roof trusses.

3
Install wall uprights and roof rafters
Install wall uprights and roof rafters

Tip: You must assemble the frame in this order to keep the structure stable during the building process.

• Begin constructing the frame of the walls by connecting the three pieces that form each of the upper wall rails.
• Connect these assembles to the tops of the former corner uprights at each end.
• Hammer in place with a rubber mallet.
• Attach the two center uprights to the base rail following manufacturer’s instructions.
• Tighten the base connections but don’t attach the tops yet.
• Install the four roof rafters over the four wall uprights you just installed. They will attach to the ridge beam on top by lining up the bracket holes and inserting a bolt.
• There will be similar brackets for attaching the bottom of the roof rafters to the upper wall rail.
• Use the spacer to make sure you place the three remaining uprights on each side correctly, then install.
• Repeat the process when installing the corresponding roof rafters.

Tip: Using the spacer ensures the panels will fit properly when they’re installed.

• The two front and back wall uprights attach to the base rail in a similar manner.
• Attach these to the roof trusses by inserting a plastic knob into the bracket and twisting right to tighten.

4
Install wall panels
Install wall panels

• Begin at one corner and insert the first wall panel, sliding in from the top along the channels of the wall uprights.
• Continue installing the panels until only the two center back walls remain.
• Attach an extended wall upright to the rear base frame.
• Slide in the remaining wall panels, then slide in the panels that will enclose the area under the roof trusses.
• Install crossbeams after each level of panel is installed.
• Attach the outer crossbeam and truss covers once the gables and walls are complete to seal the seams and help waterproof the greenhouse.

Tip: The panels are designed to fit snugly, so don’t expect them to slide smoothly into the channels.

5
Install ventilation windows (optional)
Install ventilation windows (optional)

• Attach windows by hooking into the groove on the ridge beam.
• Install the crossbeam between the rafters at the base of the window and secure the crossbeam to the neighboring rafter beams with bolts.
• Attach the handle once the windows are installed.
• Slide the remaining roof panels in position.

6
Install doors
Install doors

• Position the hinge hardware on the door jambs, aligning them with the predrilled holes.
• Fasten with screws.
• Attach the handles to the door.
• Attach the two top and bottom hinges according to the spacing indicated in the manufacturer’s directions.
• Have an assistant help you hold the door in place while you attach it to the door hinges.

7
Install supports
Install supports

Additional supports provide stability to the greenhouse. Anchor these supports to your foundation using screws. If your foundation is concrete, use a hammer drill. Customize your greenhouse by adding accessories such as shelves and hooks throughout the space.