Turning a garden box into a basic greenhouse

Since my backyard soil is rocky and alkaline with high clay content,we have been spending a lot of effort on raised garden beds as I mentioned previously in my post about soil amendments. Because of budgetary reasons, I haven't ordered kelp meal or composting worms yet. From everything that I have read, I think that both items will be a great benefit to the garden, but neither were high enough of a priority with all of the little emergencies that have come up recently. (We came home from church yesterday to a leaky toilet with water all over the floor!) Life certainly keeps things interesting, so it is important to keep your plans flexible and work toward your goals as time, efforts, and money permit.

Despite this, we were able to purchase some plastic and cover one of the garden boxes. This box was used last Spring for young chickens and turkeys with plenty of straw, wood shavings, shredded paper, and leaves as bedding. The walls and roof were constructed of electrical conduit bent into hoops tall enough to walk under and poultry netting stitched together with wire along the top of the hoop and stapled down on the long sides of the garden box frame. I ran a lightweight rototiller along the composted material and new soil amendments and was pretty happy with the 8 to 10" of dark, fluffy soil in comparison to the lighter clay soil that it was sitting on.

Rather than purchase and ship expensive greenhouse plastic, we just bought a big roll of 6 mil clear plastic from Home Depot. It isn't wide enough, so we cut it to length and used duct tape to join the seams. I cut lengths of 2x4 into strips which we used to screw down the sides of the plastic to the box. The ends of the tunnel were left loose so that we can get in an out fairly easily. This means that we have to weigh down the loose plastic with a large rock or bit of firewood to keep in the heat and prevent the wind from causing damage. Building a more permanent door is on my to-do list, but this will work for now.

In our area we get a lot of wind that is funneled from valleys along the nearby Oquirrh mountains. So with a big storm forecast for this past weekend, I was concerned that the new plastic would be blown off or torn. On the contrary, even with the cold, piercing wind, the duct tape held the seams together and the furring strips screwed down easily secured the long sides. It was the loose ends that started to pull free from their weights once the wind caught some of the loose material, but over all it held together very well. I think that the key is to keep the plastic stretched tight and secured. A digital thermometer has recorded temperatures inside the greenhouse up to 90 degrees during the day and down to the 30's at night, probably because the wind pulled loose the ends, losing a lot of its heat. As long as we can keep the ends secure, we should be able to get a jump on the planting season.

My wife was excited about planting a few cold-weather seeds so on Saturday morning she planted seeds for peas and radishes. We have seeds for several types of salad greens which will go into the ground soon as well.