It's Alive: Purdue's INhome and the Future of Biological Interiors

A good plant can really tie a room together. A fern here, a cactus there, plants are the living fixtures of the day-to-day. But what if we used plants above and beyond decoration and minor air freshening? In this year's Solar Decathlon, Purdue's INhome—the competition's second place winner—uses the biology of plants to make part of the INhome come to life.

INhome's innovative biological interior easily overwhelmed the modest exterior, turning the home into a living system. Aptly known as "biowalls," these plant networks take the purification powers of plants to larger scales. Biowalls work simply and efficiently, taking necessary nutrients from the interior air and pumping refined oxygen back in. Plants build complex sugars with only water, carbon dioxide and sunlight, all abundant resources when strategically placed in a building.

For a good animated diagram of a biowall, check out the Live Building at Queen's College in Ontario (check out the rest of the site for a truly stunning examination of the relationship between architecture and nature). You can see the plants taking in carbon dioxide and more importantly volatile organic chemicals (VOCs). VOCs differ based on location—factories tend to produce more immediately hazardous smoke while office buildings often contain adhesives and aerosols that affect long term health—but can devastate workplace health if unchecked.

Biowalls—like any garden—create miniature ecosystems. Root systems engage with the soil and create an even bigger network of mycorrhiza, a common fungus that grows on plant roots and helps the plant uptake nutrients. The plants and the fungus live symbiotically, the fungi helping out plants in exchange for excess sugars. Plants breath in carbon dioxide and the mycorrihza break down other airborne compounds. The resultant clean air gets injected back into the building.

Mycorrhiza—the stringy, shadowy white fungus—stick to the roots and uptakes nutrients


Man-made structures need not exclude the natural world. David Gissen explores this idea further with a term he refers to as "subnature." In his book on  architecture, he discusses the idea of subnature, or "those forms in nature deemed primitive," like mud, dirt, weeds and plants and how they affect architecture. We see subnature in abandoned buildings, overrun by their new cellulose-based, more photosynthetic tenants. Now, architects and builders welcome subnature.

Aside from Purdue's biowall and the Live Building in Ontario, we're starting to see larger examples of biological interiors and natural networks. A building in Morristown, New Jersey takes advantage of a three story high biowall to filter air. Another building in Toronto does the same. Different, but stunning none the less, the University of Wisconsin-Madison shields the Institute for Discovery with a network of trees representative of Wisconsin's diverse forest ecology (the interior could also be mistaken for a fledgling boreal forest).

Subnature taking over.


As we keep zooming out the question becomes, how do we make subnature part of our communities? What parts of nature can we cultivate to make our lives cleaner, safer and more beautiful? I keep thinking of a huge network of biological interiors and exteriors, root systems connecting like pipes underneath homes and buildings, all working together to clean the air. The American Society of Landscape Architects have posted a number of videos on Planet Forward extending this idea, weaving environmental corridors into urban environments.

How do you move the Planet Forward? Tweet us @planet_forward or contribute to the conversation with your own story.