Article #5

DIY Greenhouse

A greenhouse allows a gardener to grow plants when the weather is too cold to permit planting them outside. It takes advantage of the "greenhouse effect" to provide warmer temperatures (although some greenhouses are also artificially heated) and so permit planting before the danger of frost is past.

Some gardeners grow plants in the greenhouse throughout the growing season, but the more common use is to grow plant starts from seed while the weather is still cold and then transplant them to an outdoor garden once the danger of frost is past.

A greenhouse can be purchased installed on your property, or assembled from a kit. But it's also possible, and in many ways more rewarding, and certainly cheaper, to build a do-it-yourself greenhouse from framing material and a transparent covering material.

DIY Greenhouse Plans

Plans for a do-it-yourself greenhouse are readily available from our home page. The plans are detailed and highly varied. The variation happens because people have different needs and resources, and this means they want different sizes of greenhouse for different purposes.

The very smallest greenhouse is a cold frame: a wooden box with a transparent top used to grow some plant starts. Somewhat larger greenhouses can be built from wooden, aluminum, or galvanized-steel framing materials and covered with plastic film.

Larger and more elaborate structures use durable greenhouse plastic panels instead of the film. The most durable and lowest-maintenance material (but also the most expensive) is glass, which can be somewhat reduced in cost by using old windows or glass doors rather than custom glass panels.

The important decision regarding which plans to use, then, involves how big a greenhouse you want and what you want to do with it. You should also take a quick survey of your property and decide where you want your greenhouse to be located. You want a southern or south-eastern exposure that will not be shaded during the morning hours. (If it's unshaded all day, that's ideal, but shade during the afternoon is acceptable in most cases.)

 

DIY Greenhouse Dome

One very simple design for a small greenhouse uses a domed roof. Much simpler and easier to construct than a full "geodesic" type dome is a sausage-shaped construction with the greenhouse consisting of a horizontal half-cylinder.

For a small greenhouse, say 6 feet in radius, this design allows use of PVC pipe for the frame, which is generally not recommended for more traditional greenhouse construction. You can use 6 mm plastic film for the covering. The film can be ordered online or purchased at Home Depot or a similar outlet.

To build this greenhouse, first measure your space to determine what size greenhouse you want and can build. Using 3/4 inch PVC pipe, a hacksaw, PVC pipe glue, and PVC connectors, construct roughly 19-foot pipe lengths, about one for each three feet of greenhouse length.

Use a post-hole digger to dig holes for where the pipe is to be planted, each hole 3 feet from its neighbor and 6 feet from its opposite. Fix the pipes into their holes and pack them with soil and metal bar so that they form hoops over the prepared soil.

Place lengths of two-by-four along the bottom of the greenhouse on each side, inside the pipe frame. Spread your plastic film over the pipe frame, stapling it to the two-by-fours with construction staples and affixing it to the pipes with clamps.

Although this is probably the simplest DIY greenhouse, designs can be found easily online for more elaborate ones that are not that much more difficult or expensive to build. It all depends on what you intend your greenhouse for, how much space you have, and how much time and effort you want to invest.