How to Build a Backyard Greenhouse Using a Kit

In half a day, you can have a fully built backyard greenhouse with a little help from friends or family.

Project Overview
  • Working Time: 6 hours
  • Skill Level: Intermediate

In areas where gardening year-round might be a pipe dream, a backyard greenhouse can provide hours of quality garden time, even in the off-season. Maybe you want to be able to start seeds earlier or coax non-native flowers into bloom? A greenhouse of your own is the answer. However, building your mini greenhouse from scratch would be time-consuming and labor-intensive. That’s where greenhouse kits come in. Readily available online and from home improvement stores, a kit enables you to easily make one in an afternoon.

The assembly instructions for a kit can be a bit daunting, however, so we’ve made the process easier with visuals you can follow along as you build. Grab a partner to help hold up the pieces and get started on your new backyard getaway.

Related: Must-Have Greenhouse Accessories

What You'll Need

Equipment / Tools

  • 1 Level
  • 1 Step ladder
  • 1 Screwdriver
  • 1 Rubber mallet, if needed

Materials

  • 1 Greenhouse kit
  • 1 Optional accessories, such as a wall shelf or irrigation system

Instructions

  1. Find Level Location

    You'll need a flat, level surface on which to build your greenhouse. This can either be directly on grass or on a concrete foundation. Don't attempt to raise up your greenhouse on concrete blocks—it won't be sturdy enough. Lay out the base pieces in the desired location and confirm that they're level.

  2. Assemble Base

    Assemble the base pieces of your greenhouse kit and secure with the screws provided. Attach vertical corner supports to each of the four greenhouse corners.

  3. Assemble Back of Greenhouse

    Attach the taller back vertical supports, then the back horizontal and angled supports. (These should point downward in a V shape.) You may need someone to help hold up the pieces at this stage.

    Related: Our Guide to Buying Seeds

  4. Assemble Front of Greenhouse

    As with the back, attach the front vertical supports first, then screw in the front horizontal and angled supports.

  5. Build the Walls

    Slide the wall panels into the slots in the frame. Attach the side supports across the top of the panels. Screw in the top horizontal joists and gutters. You will now have roughly a box, with an opening where the door will be.

  6. Assemble the Roof Frame

    Assemble the roof trusses. This is easier to do with pieces first laid out flat on the ground. Then slide the trusses into the greenhouse walls. Install the center support beam (also known as a ridgeboard) where it meets at the roof's peak.

  7. Add Rafters and Ceiling

    Screw in the three rafter pieces. The short horizontal piece is for the vent panel. This panel can be placed at any of the four corners—it's up to you. Slide in the ceiling panels and secure. Next, install the venting latch on the small panel.

  8. Build the Door

    Slide the door pieces together on the ground, then attach the door and hinges onto the greenhouse frame. The door can be installed to open on the right or the left, depending on your preference. Screw on door hardware.

  9. Finish and Anchor the Greenhouse

    Attach any finishing hardware to the greenhouse, like the corner caps. Use the manufacturer's anchoring kit to secure the greenhouse into the ground with the stakes provided. Use a rubber mallet to tap the stakes if you are having trouble driving them. Anchoring is a necessary safety step to prevent your greenhouse from being damaged or blowing away in inclement weather.

  10. Accessorize Your Greenhouse (Optional)

    If desired, add accessories designed to go with your greenhouse, such as a wall shelf kit or drip irrigation system. Make it your own with a potting bench and stool or weather-friendly storage bins.

    Related: Keep Your Garden Tools in Tip-Top Shape

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