Soil Breakthrough Plants Hope in City Rooftops
Sourced from Michigan State University
Researchers have found a new way to boost plant growth that could make it easier to cool buildings with rooftop gardens.
It involves biochar, a mix of carbon and ash that is added to soil to prevent erosion, nutrient loss and water loss. Biochar has played a critical role for decades in forest management and agriculture projects.
One trade-off for conventional biochar is it can inhibit plant growth.
“Biochar isn’t too common in the market,” said Nate Griswold, the president of Inhabitect, a Traverse City urban landscaping company focusing on the design and construction of green roofs. Those are rooftop plant beds that naturally regulate building temperature and control water runoff.
Conventional biochar can be used in green roofs, but it’s difficult to obtain enough of the right type for a project. “Supplier A may have the product we need, but Supplier B will often have something different,” said Griswold.
A recent University of Toronto study reported on plants grown in a greenhouse using different types of biochar, including a granulated variant with a larger particle size.
“The results of the study are unprecedented,” said the study’s author, Wenxi Liao. Plants grown with granulated biochar grew 50% to 60% larger than those grown with conventional biochar. They also flowered about two weeks earlier.
A significant advantage is that the granulated biochar’s low density makes it lighter, according to the study. That could allow for larger green roofs, as their size is currently restricted by weight limits for structural reasons.
Griswold said research like this is bringing green roofs closer to universal acceptance for consumers, adding, “Year after year, the industry is growing by multiple times.”
From the Living Architecture Monitor
