Photo by Don Campbell
Science
What If Farms Didn’t Need Soil?
A vertical growing system points to a lower-carbon future for food
New grow walls in U of T Scarborough’s greenhouse are changing the way plants are cultivated, allowing crops to sprout upward in a compact, soil-free system.
The recently installed walls use hydroponic technology to produce herbs, leafy greens and other crops without soil. Instead, water and nutrients circulate through a closed-loop design that reduces evaporation and improves efficiency compared with traditional ground growing. The plants are placed in coconut husks instead of soil, providing better air circulation and water retention. A bank of LED lights casts a purplish hue, delivering energy-efficient light while reducing excess heat.
Andrew Cline, the campus horticulturalist who manages the system, says the installation serves as a growing space for both food and plant researchers who are testing how a wide variety of plants adapt to vertical cultivation. The walls also support Culinaria, U of T Scarborough’s food studies program, where ingredients grown in the greenhouse are harvested for use in teaching kitchens.
Through a work-study position, third-year biochemistry student Johar Gilaka (above) helps maintain the system, tending crops that include basil, lettuce and huacatay – a Peruvian herb also known as black mint.
The project aligns with broader sustainability research at UTSC. Vertical growing requires less space and can significantly reduce water use. By producing fresh ingredients closer to where they are consumed, the system points to a future with lower supply-chain emissions.
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No Responses to “ What If Farms Didn’t Need Soil? ”
This is brilliant. I am curious about the light intensity. Sunlight is typically 1000W/m2. What is it under these growing conditions?
U of T Scarborough horticulturalist Andrew Cline responds:
For each plant grow wall, we use three 60W LED light bars. We’ve had optimal results placing the light bars 0.15m from the plants, which translates to a 0.5 m2 coverage area. Dividing total wattage by coverage area, the estimated light intensity is about 360 W/m2 or 36% of full sun conditions.
The lights are set on 16-hour timers, from 8 a.m. until midnight, so the plants are under consistent light. Leafy greens do not require 24 hours of intense light for growth. By giving the plants exactly what they need, we're able to produce energy-efficient yields.