As I gazed out of our front window at what seemed to be a never ending frost, I wondered how we would ever get our garden off the ground this year! After researching several sources about seed propagation, early plantings and extended harvests, the answer was clear. My husband and I set our sights on building our first greenhouse in anticipation of an early spring start and an extended season of harvesting well into late fall, and maybe even early winter! After doing the necessary research, we bought the materials and began to assemble this hopeful house of harvest on our small city lot in Milwaukee, Wisconsin.

We started off by watching the sun as it moved across the sky day by day for a week. This careful observance proved to be very important in helping us to choose the perfect spot for the greenhouse. Hearing that it could very well reach temperatures of over 120ºF inside during our hot and sweaty Wisconsin summers, we chose a site that would receive the morning sun but by 2:00 p.m. in the afternoon, at the peak of the heat, the neighboring trees would give needed relief. In addition, we designed it so that the plastic covering could be peeled back and clipped to the framework, allowing any cool breeze that happened by, a lazy window through-way right down the middle of our greenhouse. It was exciting to dream about the coming season.

Our next step was to clear the grass from our chosen site and begin to lay in the foundation. Our foundation consisted of used 8' x 8' timbers formerly used as a retaining wall. These are not the creosote-soaked railroad ties, but the treated landscape timbers used for retaining walls. The cost was "free-you haul." We couldn't get there fast enough! On our way we saw a pile of pallets outside of a small factory with a "Free" price as well. These would be our walkway, keeping the mud levels down on the floor of the greenhouse. We bordered the walkway with 2 x 8 pine boards to keep the dirt in the beds and not in the aisle. This allowed us a four-foot bed on each side and in the rear of the house.

Our next step was to fill in the framework with a good planting mix. We read several articles on how to measure pH levels in soil, what to add for balance and what the various plants we knew we wanted to grow would like in the way of optimal pH levels. We bought a load of about three yards of good planting mix from a landscaper and purchased an inexpensive pH level indicator from the hardware store. After measuring the pH levels, we learned that our soil needed bone meal and agricultural limestone (not lime) to get the perfect balance for our crops. We also added some sand in hopes of perfect drainage. Since every soil mix is different, we can't give any advice on how much of each ingredient to add, but we can recommend going to the public library to learn about the optimal pH levels for common crops such as tomatoes, squash, cucumbers, peppers, onions, and the like. Without that knowledge, it would have been a tossed coin as to how good our harvest would be.

Being on a fixed income, we wanted a framework that would be relatively inexpensive and simple to construct. So we settled on common 3/4-inch gray PVC pipe and connectors for the cross pieces. We also needed a way to secure the poles to the framework and found that plumbers' clamps worked the best. The next step was to put the framework together, so we laid everything out in the yard and pondered how to do it. We wanted a center pole running horizontally down the length of the greenhouse to hang lightweight planters, misting hoses, and maybe even fluorescent lighting. To get that, we had to cut the 10-foot poles that would make up the main framework in half, connect them to the cross connectors using PVC glue and cut five two-foot pieces to connect to the cross pieces, which would make up the center pole to the ribs.

Attaching them to the framework was very simple, but definitely takes two people! We attached the pipe clamps at two-foot intervals along the length of the timbers-front, rear and middle ribs first, then the two remaining ribs. Next, we built a front framework out of 2 x 4s to hold a door. The door itself was simply made of 1 x 4s, two hinges, metal joiners, and screen attached to the front. It was exciting to see it all materialize right before our eyes!

Our next step was to drape the 10' x 25' roll of 4 mil plastic over the framework. (Ed. Note: We've had problems with 4 mil lasting through the winter. If you live in an area with severe winters, you may want to use a thicker plastic or even a special greenhouse plastic.) We had to cut the sheet into two pieces horizontally and drape it over the sides to make it fit. We attached the sheets to the pole by cutting scraps of the PVC pipe in a little more than half, lining the pole with a two-inch square piece of old bicycle tube rubber between the plastic and the outside and then placing the "clamp" over the rubber tubing. This made a secure clamp to hold the plastic on the frame and yet we could remove it easily on hot days to lift the plastic up. They also came in handy to clamp those flaps onto the framework, allowing air to flow through the house uninterrupted. We used a scrap piece of the 4 mil plastic for the rear of the house and for the front of the house, other than the front door.

At this point all that was left was the planting. It was the beginning of March when we started this project, and still pretty cold outside. We waited a few days before planting our seeds in order to see just how warm it might get inside the greenhouse this time of year. We purchased several very inexpensive thermometers at the variety store and stuck them into the dirt in various corners of the beds, and also placed several around the house to see what the air temperature would reach during this time of the year. We were amazed to see that the air temperature would reach 70ºF inside with a 40ºF outside on a sunny day! The bed temperatures however, reached a mere 60ºF. Not quite warm enough for most seeds, but plenty warm for the early spring crops such as onions, radishes, lettuce, broccoli, cauliflower and strawberries. Just two weeks into the month of March and we had the beginnings of a prolific garden breaking the crust of topsoil.

Our last project was to design and implement an inexpensive watering system. Fortunately for us, a local building supply house was going out of business and we were able to purchase everything we needed to construct a drip watering system at a fraction of the cost. We've found the drip system to be more fruitful for us than bulk watering with a sprinkling can or hose. When we bulk watered, we found that we were over-watering some areas and not enough in others. The drip system allowed us to connect drip heads wherever needed. They come in varying flow levels, so we were able to turn the water on and each plant received the amount of water it needed to grow.

With that done, all that was left was to enjoy the earth smells, humid air and overall good feeling sitting in our greenhouse on chilly mornings. As the season progressed, we found the air temperatures reaching 120ºF, with the ground temperatures reaching 80ºF. Our plants started to wilt with the heat. We experimented with the temperature by raising the flaps throughout the day and lowering them as the sun started to wane. Our plants sprang to attention with that and began to put out all that we had hoped for. We had an early harvest of onions, lettuce, radishes, strawberries, tomatoes, peppers and eggplant. Our extended harvest into the late fall left our family and friends envious.

You can grow just about anything in this inexpensive greenhouse. If it gets too hot, simply peel back the plastic sheeting or remove it altogether and watch your harvest grow.

Supplies for this greenhouse:

• 12' x 16' of ground framework material (we used landscape timbers)
• 3 pallets, for flooring
• 10' x 25' roll of 4 mil or thicker, clear plastic sheeting
• 5 3/4-inch x 10' PVC pipe
• 3 3/4-inch PVC cross tees (for top/middle supports)
• 2 3/4-inch cross tees (for top/end supports)
• 10 3/4-inch pipe clamps
• Dirt
• pH tester
• Soil amendments