How to Build a Greenhouse

Keith and Renee Johnson live on a picturesque plot of land amid rolling hills in rural Wisconsin. They ran a small hobby farm for about 30 years and always wanted a greenhouse. Family Handyman teamed up with them to build this greenhouse so they could start seedlings for their garden just a few steps away.

Build the foundation

We removed eight inches of topsoil to make room for our base layer of rock. We leveled and compacted the dirt, rolled out heavy-duty landscape fabric, then added at least a two-inch layer of 3/4-in. limestone.

Next, we created a mini retaining wall out of landscaping timbers. We placed, leveled and squared three sides of the retaining wall, leaving the fourth side off until dumping most of the rock.

We secured the timbers at the corners with eight-inch timber screws and fastened a pressure-treated board to keep the timbers together at the seams. When most of the rock was dumped and evenly spread, we built the fourth side. Then we leveled off and compacted the rock with a tamper.