How to Build Greenhouses in Windows

Potted herbs are great plants for a window-mounted greenhouse.

Greenhouses make it more practical to grow plants year-round than traditional gardens or potted plants that you must move inside in the winter. One space-saving design allows you to keep a few plants, like herbs, in a window-mounted greenhouse; it is a convenient plan in an apartment or a home without the room to build a greenhouse in the yard. It is a project that you can finish in an afternoon, with the proper tools.

Things You'll Need

• Measuring tape
• Paper
• Pencil
• 1-by-4-inch pine lumber
• Jigsaw
• 1/2-inch pine platform board
• Acrylic window-well cover
• Plywood
• Screws
• Screwdriver
• 1 3/4-by-5-inch clip plates

Instructions

1. Choose a window for your greenhouse. You want to use a window that receives sunlight throughout the year on the south or southeastern side of a building. This way, your plants get sunlight for most of the day.

2. Open the window. Whether it opens vertically or horizontally, measure the distance from the sill to the top of the opening and between the seals on either side of the window. Record the measurements on paper with a pencil. This design works best for a window that opens vertically.

3. Cut three pieces of pine lumber from 1-by-4-inch lumber: Two should be 1 1/2 inches shorter than the vertical measurement for the sides of the window frame, and one, the horizontal measurement for the top of the window frame.

4. Saw a platform board out of a 1/2-inch piece of pine for the floor of the window greenhouse. You want it as wide as the horizontal measurement and as deep as the acrylic window-well cover. Hold the bottom of the window-well cover to the board and draw a line with a pencil outlining the edge of the floor, so you know where to saw. The part of the platform that sits outside the window can be wider than the window, but the part that forms the bottom of the frame should only be as wide as the window. For any discrepancy, make an "L" shaped cut at either side of the platform where the frame sits up against the edge of the window so the long side of the "L" is flush with the outside wall.

5. Hold the side of the acrylic window-well cover to a piece of plywood and use a pencil to trace an outline of it. This piece is to cover the space from the top of the window-well cover to the top of the frame, and from one side of the frame to the other. Measure accordingly, and saw the shape you've drawn out of the plywood.

6. Screw the frame together. Attach the top of the frame to the ends of the sides of the frame. Screw the outside of the greenhouse you cut in Step 5 to the frame. Connect the floor of the greenhouse to the sides and the outside of the frame. Caulk the window-well cover into place.

7. Attach 1 3/4-by-5-inch clip plates to each of the four corners of the frame on the inside edge, and fit the frame into the open window. Screw down the clip plates to the sides of the window.

Tips & Warnings

• Tack fabric to the wood in your greenhouse, so it matches the decor in your window. You can also install snaps or strips of Velcro to hold it up.

• To put a tray in your greenhouse as a planter, saw a hole in the floor large enough to hold the tray, but small enough that the upper lip does not slip through. Make sure the tray is outside of the window sill hanging into the air, so it does not catch on the sill.

References

• Mother Earth News: A Garden in the Window
• West Virginia University: Planning and Building a Greenhouse