Constructing a Temporary Greenhouse

I used 10' lengths of PVC pipe and joined two with a connector to make a 20' length for each rib. I had the ability to make the greenhouse as tall or wide as I wanted. You will have to decide for yourself the size you want yours. That being said, remember it'll never be big enough no matter how large you make it. If you have neighborhood deed restrictions, check there first. You may also want to let your neighbors in on your plan. I was fortunate enough to have started my next door neighbors down the path of plant addiction over 5 years ago. Your neighbors, however, might not think it's something they want to see from their upstairs deck all winter.

So decide where you want to place your greenhouse, make a plan and then get to the big box store.

Here's a partial supply list to get you started, depending on what size greenhouse you want to build:

1/2 " white PVC pipe for the ribs and purlin
Pipe connectors
Box of 1 5/8" drywall screws
2' pieces of 1/4'' rebar ( 2 per rib)
Duct tape
Spring clips
Batten tape
Plastic sheeting 6 mil

Tools:

Portable drill
Drill bit to start the screws
Phillips screw driver
Hammer
PVC cutter or saw

Gather your supplies and equipment, preferably on a sunny, calm day. Mine goes against the fence and is high enough to cover some tropicals but low enough that the neighbors don't see it from their garden. By now you've already decided how big you want yours and have drawn out a plan. You do have a plan, don't you?

  About every 4' and close to the fence line, I hammer a piece of rebar into the ground and slip an end of PVC pipe over the rebar. You may decide to make a much smaller gh, so your rebar might be closer to 2' or 3' apart. It just depends; the closer the ribs, the sturdier the structure in the wind, rain, and snow.

As you have already decided how high and wide you want it, you should now attach a purlin (the pipe that attaches horizontally to the ribs across the top of the gh and holds the structure together) 1/2 the length of your pipe ribs. Since I use two pieces of 10' pipe, it's easy to know where the middle is going to be. If you're making a shorter, or smaller structure, just measure halfway on each pipe rib and mark it. The purlin should be screwed across the top of the ribs. It's a good idea to duct tape these screws so they don't rip the plastic. It's best to do this before you try to raise the ribs. Line up each rib evenly to the other side of your greenhose, and then hammer rebar on that side of the area you're covering.

Slip the other side of each of the ribs onto the rebar. You've just built a greenhouse all by yourself!  Now you have to cover it!

Unless your gh is very small, you'll need help unrolling the plastic and hoisting it over the gh frame. Before you cover the structure, make sure to cover any screws that may tear the plastic with duct tape. My daughter helped me unroll the plastic, but we could have used another pair of hands. Make sure to leave enough plastic on both sides of the structure. Since mine was along the fence line, I was able to secure the plastic to the fence by screwing the PVC pipe to the fence with the plastic between.

Depending on where you locate your greenhouse, the wind may be a factor. We use black batten tape to keep the structure from flying into the neighbors' yard. You can attach it to the ground with tent anchors, or if it's against a fence, drill one side of the tape into the fence and take the other side over the greenhouse and anchor that end to the ground. We secure it diagonally. To close the bottom of the greenhouse, you can run a board along the bottom and staple the plastic to it or you may just use bricks or rocks. We'd done both. The problem with using a board is you can't easily raise the side when it's a warm day. Use some spring clips to secure the plastic to the PVC pipe at the bottom of every other rib, depending on how long or large your greenhouse is. It will help when the fronts blow thru!  You may want to run a length of PVC pipe across a couple of the ribs to stabilize it when the wind blows. Attach it from one side of a rib to the other with screws.

The ends of your greenhouse plastic can be folded over and secured at the bottom, or you can add a small door if your greenhouse is a larger one. Either way, leave yourself a way to get in and out. At some point, you'll want to go in and check on things, to water, add a small heater, or just smell the flowers.... I always string large Xmas lights in mine. They give off a small bit of heat in a large gh, and a surprising amount of heat in a smaller one!

When the days start to warm, you may roll up one side of the greenhouse and begin to let your plants acclimate.  DDon't do this on a windy day, though. Your greenhouse may wind up in the neighbors' yard.

As soon as spring comes, take off the plastic, fold it up into a little square and store it. Disassemble the pipe and hide it behind the storage shed. Your garden has a head start into spring.