There are thousands of pounds of plants and soil on board
Because Swale is on the water, it poses an interesting challenge: how, exactly, do you make sure there is enough soil and gravel for plants to grow, without the barge sinking? Then add a few dozen people, walkways, a greenhouse theater for events, and now -- a hill for apple trees to grow on.
Managing the weight on the barge was one of the challenges tasked to Subhram Reddy, an engineer who leads the onsite operations on Swale. This winter, in particular, he had to rework Swale’s layout to accommodate a hill on board for the apple trees Strongbow provided.
“Eventually, we wanted the forest to take over the barge, we wanted it to spread. We wanted to remove the planters, and let there just be forest and plants,” Reddy says. “This is step one.”
Every aspect of Swale was first weighed and laid out on a computer before a single seed was planted. For the plants to be able to retain some water, a level of gravel was needed underneath the soil and compost. Just one cubic yard of gravel, though, can weigh up to 3,000 pounds. To alleviate that, the team chose lava rock to act as a substrate. It weighs about half what traditional gravel does. Even so, each planter on board weighs between 250-300 pounds, and needed to be lifted on-board with heavy construction machinery. Now the artpiece accommodates 50 tons of soil, 10 tons of gravel, 15 tons of lava rock, and 200 edible perennial plant varieties.