City residents could get to eat Boxcar Willie in about a month if all goes well at an experimental rooftop garden at the Hole’s greenhouse.
About 20 volunteers gathered at the Enjoy Centre Thursday to pour dirt and plants into four rooftop gardens. The gardens, installed last August but not completed until this week, are part of an experiment by the Northern Alberta Institute of Technology (NAIT) to test out the effects of plants on Alberta roofs.
Roofs go through big temperature swings over the course of the day, says David Critchley, head of NAIT’s living roofs in cold climates research team, and all that expansion and contraction wears them out. You can even out these swings with plant-covered green roofs, reducing wear and tear and the need for heating and cooling.
The NAIT team has set up four boxy modules on the roof of the Enjoy Centre. “They’re minimum-code buildings, essentially,” he notes, as they have heat, a roof and a door. “We’re trying to approximate a typical roof.”
Each module contains dirt (custom-made to have specific nutrient and water-retention levels), sensors and plants. The NAIT team will track heat, moisture, photosynthesis and carbon storage rates in the modules over the next five years to track their effects on energy use and see which plants survive.
In a parallel experiment, the team has also set up 61 tomato plants on the roof to see if they can grow local food.
Roofs are essentially microclimates, notes Enjoy Centre co-owner Jim Hole, and are often way hotter than ground level. He’s hoping to show that rooftop gardens can grow plants like vegetables faster than ground-level ones without affecting taste.
And they’re not growing ordinary tomatoes, either, Hole adds – these are black, purple, and striped ones with names like Boxcar Willie and Amish Paste.
“These are tomatoes that have been handed down from generation to generation,” he says, and haven’t had their taste bred out of them like modern ones.
The team is growing 28 varieties in all, Hole says, about 80 per cent of which are heritage tomatoes. If all goes well, the vegetables should be ready for the Prairie Bistro restaurant downstairs by August.
These experiments should gather some great data, Hole says – data he hopes to use to create a permanent green roof atop the Enjoy Centre.
“We’re interested in being as sustainable as possible, so, if we can adapt that technology, which I think we can, for our roof, it’ll be great.”
