Wow, a two-story greenhouse! Lauri built a surprise for his mother out of old windows

In the fall a couple of years ago, I noticed a dumpster in the courtyard of an apartment building in Helsinki. I peeked inside and realized I’d struck gold: it was full of windows, all intact and neatly stacked side by side, awaiting a trip to the landfill.

I immediately called my mother to let her know I’d be visiting that same day. She lives in a detached house in the countryside, surrounded by a large, flourishing garden. I mentioned I was bringing along a small surprise that I thought might delight her.

The main facade of the greenhouse faces south-southeast. Mint also grows abundantly in the shaded northeast corner of the herb bed that surrounds the greenhouse.

Sturdy, angled stairs securely fastened to the frame lead up to the second floor. From there, you can cross a walkway to the other side of the greenhouse.

A two-story greenhouse required improvisation

Early the following spring, my mother and I measured the tree heights and tracked the sun’s path, considering the best spot for the greenhouse. On a wooded lot, we had to choose the location carefully so the greenhouse would get as much sunlight as possible.

Once we settled on the location, I got to work. Since I’m someone who has a tendency for improvisational building, my guiding principle was simple: I wanted to build a two-story greenhouse that would be a paradise for both plants and people.

The project required plenty of creativity. The windows I found were slightly different sizes, and putting them together felt a bit like solving a puzzle.

The greenhouse’s wooden framework stands on its own atop cinder blocks. The windows are waiting to be installed in their proper positions.

It’s easy to set up a network out of jute string for climbing plants to use as a trellis and support.

Installing the windows on the two-story frame

We chose a spot on solid bedrock for the greenhouse, so I made the foundation from cinder blocks placed at the corners of the house and halfway along each side. I cemented them to the bedrock and added a layer of bitumen felt to insulate the wooden structure above.

Two-by-fours were enough to support the greenhouse’s framework, which rises to around five meters. I arranged the windows on the frame one by one. Rather than screwing the window frames in place, I simply let them rest against the structure, secured by trim on each side.

The windows were all different sizes, so despite careful assembly, small gaps remained here and there. I decided to make use of them by making them into ventilation openings—I would have needed to make some in any case for temperature control.

With a height of nearly five meters, there’s plenty of space for tomato stems to climb. The upcycling spirit of the greenhouse continues in the hanging baskets made from old wood stove burners.

Incorporating growing boxes into the foundation

As the mosaic of windows rose layer by layer and reached the ridge height, it was time to install the roof. I chose transparent roofing panels sturdy enough to handle any branches blown down by fall storms.

After finishing the roof, I turned my attention to the floor. I decided to incorporate growing boxes into the foundation right on top of the bedrock. I placed them under the wooden structure, partially inside and partially outside the greenhouse. This setup allowed them to serve as both plant beds and insulation, while preserving precious indoor space for a seating area. I used leftover roofing panel pieces to seal the gap between the soil and the wooden frame, and I lined the wooden surfaces of the boxes with vinyl flooring to protect them from moisture.

All that was left was painting and finalizing the interior, and my two-story greenhouse was finished.

After two weeks of intense work, I could finally return to life’s fundamental questions—choosing and planting crops and, most importantly, watching them flourish.

Later in August, my mother and I were sitting in the greenhouse, enjoying the slowly darkening summer evening, a good wine, and the intoxicating aroma of tomatoes all around us. The peppers were glowing red, the beans had already climbed up to the ceiling, and our chili experiment was nearly a success as well.

A plant tower made of wooden slats extends to the ceiling between the greenhouse’s second floor and the L-shaped walkway. Baskets hanging on the tower and from the ceiling are easy to water from the walkway.

The cozy seating area on the second floor is perfect for morning coffee. Behind the greenhouse, there’s a gutter and downspout for collecting rainwater.

Lauri’s guiding principle was straightforward: build a two-story greenhouse from recycled materials to create a paradise for both plants and people.

Lauri’s tips for building a greenhouse from recycled materials

Where to find old windows?