Last month we reported on Local Garden, a new commercial vertical farm located in downtown Vancouver. Last week I was in Vancouver and had the opportunity to check out the vertical farm that is located on the top of a parking garage. The farm was extremely welcoming, allowing me to come inside, take pictures, and ask away about how it all works.
About the Farm:
Local Garden employs a conveyor-belt system of towers, each with 24 hydroponic racks that are filled with produce (mainly leafy greens). The towers move around a looped system in order to gain optimum access to sunlight for the crops during the day. Local Garden looks like a greenhouse but doesn’t use glass as its main facade material. Instead, the structure is covered in a special clear plastic that is designed to reduce the added weight that a structure like this could cause, and the material also directs UV light for the plants better than glass would.
At night, the crops are lit by grow lights that are staggered in height so that each tray receives relatively equal amounts of light. I arrived there at about 4pm and by the time I left it was dark outside. The whole structure had this bright green glow and eventually curtains came down to reduce the light pollution for neighbors in the area (something that the farm is not required to do but still does out of respect for its neighbors).
Remember, these systems are designed to grow food locally in dense spaces, which is why optimizing the production of food within the limited space available is key to the success of the concept the business depends upon. The reduction of resource inputs is also of paramount importance. Here are some of the questions I posed to Local Garden:
How do you irrigate the crops?
Water and nutrients are added to the irrigation system which is piped up above the towers. Then, the nutrient-filled water runs into the top tray of crop. A hole at the bottom of each tray allows the water to flow through each tray and then down to the next. Finally, the water left over leaves the bottom tray, is collected in drains, and recycled back into the system.
Where do you get your seedlings from?
Seedlings are brought in from a local farm just outside the city. Local Garden has plans to expand and build a second structure that would be a seedling station next to its current site.
What was your biggest cost during construction?
Strengthening the parking garage to manage the weight of the greenhouse was the biggest cost. This information is consistent with what most building-integrated agriculture projects suggest but I was still surprised. Local Garden didn’t use glass (heavy) and keeps its water tanks on another floor (also heavy). Clearly, weight and structural integrity will remain core challenges to BIA. New materials like the clear plastic employed by this project will become increasingly more important.
What do you expect your biggest overhead cost to be?
Energy costs are likely to be the biggest costs. The energy required to move the conveyor belts around and energy to power all of those grow lights. The farm has not been open long enough to tell what percentage of their monthly costs is energy but I plan to check in with them 6 months from now. It was interesting to me that energy was cited as the highest cost as energy in British Columbia is among the cheapest in North America. This is another testament to the challenge that energy is, and will continue to be for building-integrated agriculture.
How many farmers are there each day?
There are 4 farmers needed to manage the farm.
What are some of your biggest unexpected challenges?
Crops on the lower trays of the towers don’t do as well as those above. As the water filters down and through the 12 trays, the bottom ones always seem to have a slightly more difficult time. They still do well but are not as good as those above. This challenge was truly interesting to learn about. The Local Garden system is extremely water efficient but clearly there are trade-offs. Finding the ideal balance in controlled environment agriculture requires trial and error. For example, perhaps less trays on each tower or two separate conveyor systems would provide nutrients more evenly to all of the crops.
What yields do you expect to produce?
Local Garden expects to produce 400-500 pounds of fresh vegetables each month. They sell their produce to high end restaurants in the neighborhood and some supermarkets. I was happy to hear that they are able to compete with most of the produce on the market.
Vertical farming is still in its infancy and many challenges still need to be worked out. Density is essential to making the best use of land in urban spaces and producing the required yields to turn a profit. When density increases, so does the weight of the structure and the difficulty in providing balanced light for all of the crops. Energy, rent, and, structural materials will continue to be difficult challenges for dense urban farming.
People often forget that every farm is an experiment. Farmers attempt to produce yields under conditions that they think will increase yields. Controlled environment agriculture is the same except that the variables of light, water, nutrients, and, temperature can be tested more intricately. Local Garden has taken on a lot of risk with their vertical farm in Vancouver. I look forward to seeing how they succeed and how they adapt to the challenges ahead.