DIY: Glasshouse Greenhouse

Greenhouses attached to the house are often called conservatories.

A greenhouse is a convenient place to start plants early in the spring, and keep them blooming when the growing season has passed. Unfortunately, buying a glass greenhouse kit can be cost prohibitive. This does not mean, however, that owning a greenhouse is out of reach if you're on a budget. With a little hard work and careful planning, you can build your own glass greenhouse from old windows and basic carpentry supplies.

Things You'll Need

• Wooden frame windows
• Basic carpentry tools
• Nails
• Screws
• Caulk
• Bricks or Gravel
• Concrete
• D-anchors
• 1-bys or trim board
• Box fan
• Glass door
• Two-by-fours

Instructions

Structural Planning

1. Collect old windows in wooden frames. You will need about 50 windows in all, though having some extras is a good idea, in case some do not fit easily into the design or break during construction.

2. Get a box fan and a glass door for your green house. The fan will provide the greenhouse with necessary ventilation and circulation. Measure both and record their dimensions.

3. Measure all of the windows you have collected, and record their dimensions.

4. Sketch out a design for your greenhouse. Decide if it will be a lean-to off of another structure, or a standalone building. Draw out each wall, using the dimensions of the fixtures you have collected. Plan to build the door into the center of the front wall, and the fan into the center of the back wall. There will likely be gaps between your windows; try to minimize their size so that they are easier to fill in later.

5. Lay the windows, and other fixtures, out on the ground to create a dry run of your walls. This will allow you to see if the windows are a good fit, or if your need to do some rearranging.

6. Cut sections of glass from your glass sheet to fill in any gaps in the design. Frame them with inexpensive 1-by lumber or trim board and lay them into the dry run walls on the ground.

7. Select a location for your greenhouse. Select a level location in full sun, in an area that drains well. If you are planning a lean-to style greenhouse, build on the south side of the structure.

8. Draw out a foundation for your greenhouse with stakes and string. Drive stakes into the ground where the four corners of the greenhouse will stand, and run string around them to form the outside square of the foundation.

Greenhouse Construction

1. Dig a trench under the string that marks the foundation. The trench should be about 1 foot deep, and between 18 inches and 2 feet wide.

2. Pour concrete into the trench, filling the space completely. Put ½-inch D-anchors into the concrete at the four corners. The D-anchors will allow you to attach the greenhouse structure firmly to its foundation. Allow time for the concrete to cure.

3. Set four-by-four posts inside the foundation at each corner. Bolt the four-by-four posts to the foundation using the D-rings.

4. Frame in the walls. Create these frames from two-by-fours. Remember that the roof needs to be sloped, so the front of the walls should be slightly higher than the back of walls. Construct the basic outer frame for each wall, with vertical supports at whatever width works best for the windows you have selected. Put in cross braces according to the size of each individual window. This will create a two-by-four frame where each window can be attached.

5. Set up the walls. Place them against the vertical four-by-four posts and use nails to secure them both to the posts and to each other.

6. Build a frame for the roof. This can be a simple frame that matches your walls, with vertical supports that are the width of your roofing material. Attach the roof frame to the walls.

7. Cover the roof frame with greenhouse felt, or corrugated metal sheeting. You can also build a window or two into the roof, just as you built them into the walls; however, if you use windows for the entire roof, it is extremely likely that your summer greenhouse temperatures will be too high.

8. Attach the windows to the framed-in walls by driving nails or screws through the wooden window frames and into the studs.

9. Place the fan into the framed-in location left for that designation. Use 1-by lumber, or trim board to frame in into position, and make its edges more attractive.

10. Add finishing touches. Use an outdoor caulk and seal between the windows, or anywhere else there appears to be a crack or gap. Cover the floor with large gravel or bricks. Paint the wooden frames around the windows, and add planters and greenhouse benches.

References

• Sustain Lane: How To Build A Greenhouse From Old Windows
• Build Eazy: How to Build A Greenhouse
• Mother Earth News: You Can Build Your Own Add On Greenhouse