How We Built a Lean-To Shipping Container Greenhouse: From Sketch to Growing Space

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When we first got our shipping container, we knew we wanted to do more with it than just use it for storage while we were building our house. With good southwestern exposure on one long side and a growing interest in extending our planting season—not to mention protect plants from all of the elements and critters that do a good job of killing or eating them here in northern Arizona—we decided to build a lean-to style shipping container greenhouse, and it's become a year-round space for a variety of edibles.

We worked with the owners of Steady Harvest, who used my simple sketch to help us bring this idea to life. The greenhouse structure is a lean-to design, with one long side of the shipping container forming the back wall. This gave us both structural support and thermal mass to help regulate temperatures inside.

This is the sketch I gave them, which they used to design the greenhouse:

We didn't end up using the EF Block (which is a brand of ICF block we had left over from the construction of our house) as shown in my sketch, so the bottom rail of the greenhouse sits on the ground instead. The framing is galvanized steel pipe, with translucent polycarbonate panels of a product called Solex for the roof and side walls, and a long roll-up screened side for airflow. The doors at either end also have screened windows we can open for additional ventilation. The roll-up side and floor of the greenhouse are lined with 1/4-inch hardware cloth to keep out the field mice, pack rats, and bunnies, who all want to eat what we grow. But the wee lizards and some pollinators can still get in (we sometimes prop the doors open during the day to let the bees easily come and go). The photos below show the greenhouse during and after construction was complete.

Adding Rainwater Collection to our Shipping Container Greenhouse

To make our greenhouse more self-sufficient, we installed a simple rainwater harvesting system. We mounted a vinyl gutter along the roofline on the roll-up side, which channels rainwater directly into an IBC tote positioned at the back end of the greenhouse. The tote is fitted with a black zippered cover to minimize algae growth in the warmer months and help protect the water from freezing during winter. It’s an easy upgrade that makes a big difference—sometimes capturing hundreds of gallons from just a single rainfall and giving us a steady supply for the plants inside.

Adding Ventilation to our Shipping Container Greenhouse

Even with our roll-up sidewalls and screened doors at both ends, we quickly realized our greenhouse needed more ventilation to keep things cool during the warm and hot months. To solve this, we added a pair of automatic louvered vents to the upper section of the greenhouse wall above the shipping container. These vents open on their own when the inside temperature hits a set point, thanks to an autovent cylinder that expands and pushes the louvers open—no electricity needed. The vents automatically close when the temperature falls back to a lower set point.

The vents have made a huge difference in reducing heat buildup, especially during peak sun hours. Because they’re placed high up, they help release rising hot air efficiently and keep the air inside the greenhouse circulating. If you’re building your own greenhouse or retrofitting one like we did, adding solar-powered or thermally activated vents can be a game-changer for passive climate control. As you can see in the photo above, we also use some greenhouse shade cloth inside, which we can slide across the steel frame as needed to further diffuse the sun and protect plants during the hottest summer months. (Shade cloth can also be used over the exterior of the greenhouse, which is more effective for climate control.)

Building a Custom Shipping Container Greenhouse

This 12x20-foot greenhouse has become one of our favorite places on the property. It’s where we start seeds, harvest greens for dinner, and escape into something green and growing even in the middle of winter. It’s also been a great teacher—showing us what works, what doesn’t, and how a bit of creativity (and a few practical upgrades) can turn a simple idea into something that truly supports our way of living. If you’re dreaming up a greenhouse of your own, we hope our setup gives you some ideas to run with. Our custom shipping container greenhouse is featured on the Steady Harvest website, where you can order it (we would not receive a commission from that) if you'd like to do something similar. Do you have a shipping container greenhouse or questions about ours? Let us know in the comments.