Build a Low-Cost Low Tunnel Greenhouse

Have you ever smelled fresh, warm earth from a cold-frame or greenhouse in the dead of winter? The smell has the ability to transport you back to warmer seasons. For most people, the luxurious, warm, moist air of a solar space used to grow plants and create miniature eco-systems is out of the question, due to high heating costs and the price of building such a configuration. There is a low cost solution to growing vegetables in the winter, using nothing more than plastic, black water pipe, a few pieces of rebar, and a rope to tighten it all together. The easy to build structure is called a low tunnel, and it takes just a few minutes to erect.

First, cut some pre-curved, black water pipe to ten feet long. This type of pipe can be found at most hardware or plumbing supply stores and usually run a few dollars. I use high-density polyethylene black plastic water pipe that I picked up at a farm sale for five dollars, but can be purchased new for around twenty dollars for a 100 foot roll. The ten foot pieces, when inserted over re-bar stakes cut to a foot and a half and plunged into the ground, will stand around three feet tall when spaced five feet wide.

Next, plunge 18-inch cut pieces of rebar into the ground about a foot deep parallel to each other to fit the pipe over, making a sturdy pin to keep the pipe standing upright. Continue plunging the rebar into the ground about two and a half feet from the next, place the pipe over the rebar to create the frame for the low tunnel.

Once the framework is set up, the next step is stretching the plastic over the frame. My 25 foot low tunnels require a 10 foot by 25 foot piece of 3-6 mil., clear plastic sheeting. These come in rolls of different sizes, and will be the biggest expense for this project. Simply roll the sheet out and lay it across the framework. Bunch up an end of the plastic sheeting and tie it together by wrapping a rope around the end. Place the end on the ground and drive a stake through the plastic in front of the rope tied around the bunched up plastic. This stake will be used to anchor the low tunnel and keep it from blowing away. Do the same with the other end, but do so making sure the slag in the plastic is tightened by pulling the remaining plastic and stake tightly to the ground.

The next step requires a long, strong rope to tie crisscrossed over the structure. You'll start at the first stake and tie it off. Throw the rope over the structure and wrap the rope around the bottom of the opposite pipe where the re-bar is holding the pipe in place. This will create a crisscross pattern until you reach the last pipe, to which you can cut the rope and tie it off. As you tie the rope, pull it tight, this will help strengthen the structure and will also help with the snow load during the cold, winter months.

The rolls of sheeting will run about 15 to 25 dollars with the longer pieces running around a hundred dollars. A longer piece will be required for the farmer who wants to cover a few long rows. For the backyard or kitchen gardener, one 25 foot low tunnel is all that is needed to feed a small family and supplement the diet with fresh greens over the winter months. For the more ambitious, a number of these smaller low tunnels can be put up, all with different climates. Experimenting is the key to finding hardy varieties that thrive in these environments.

There you have it, a low-cost low tunnel to grow delicious vegetables in the winter at a fraction of the cost it would take to build a larger and more permanent structure.