Grass clippings, tree trimmings, banana peels, and coffee grounds might sound like things you’d throw in the trash, but here at the High Line, these are all raw ingredients for “black gold,” better known as compost.
Maintaining the High Line's more than 100,000 perennials, grasses, shrubs, and trees requires our gardeners and custodians to handle large quantities of waste plant material. As part of Friends of the High Line’s commitment to sustainability, we ensure that all of this material is composted. We are able to send the majority of our leaves, grass clippings, and branches to the New York City Department of Sanitation’s impressive composting facilities in Fresh Kills. This year, the High Line is proud to be expanding our composting program by piloting a two-bin composting system for processing small quantities of organic waste on-site. High Line Gardeners Maeve Turner, Meg Graham, and Kaspar Wittlinger spearheaded the project, constructing the compost bin and fine tuning the balance of raw materials. Working with the High Line Food program  we have found ways to integrate High Line vendor waste into our compost. We add coffee grounds from Blue Bottle Coffee , and food scraps from Friends of the High Line’s administrative and operations offices. These materials together provide the perfect environment for the organisms that convert these raw ingredients into finished compost.
So far, our on-site composting has produced a few cubic yards of compost. This compost will be used to make “compost tea” next spring, an aerated compost solution that will be used as a soil amendment and spray on the surface of our plants to help keep them healthy.
The main ingredients of a successful compost pile are carbon, nitrogen, air, and water. Each of these components plays a specific role for the organisms that break down plant debris and food scraps into finished compost. There are physical decomposers (such as pill bugs, worms, and mites) and chemical decomposers that break material down with chemicals from their bodies (microscopic organisms such as bacteria and fungi). All of these organisms require oxygen to breathe, water to keep them hydrated, and carbon and nitrogen to fuel their metabolism and create enzymes and proteins that act as a food source.
Carbon comes from “brown” garden materials such as autumn leaves, straw, wood chips and brown garden cuttings such as dead grasses that are cut down in the spring. Nitrogen comes from “green” garden materials such as grass clippings, fresh garden cuttings, kitchen food scraps, and coffee grounds. Air is supplied by frequent turnings of the pile and water is supplied by rain on an outdoor pile, or watering during turning if the pile is covered. A successful compost pile is layered with browns and greens, well watered, monitored for temperature change, and turned as needed, sometimes once or twice a week.
LEARNING TO COMPOST AT THE HIGH LINE
Composting is something anyone can do at home, even in NYC!
On Saturday, October 1, High Line visitors joined us for Learn to Compost in the City , an introduction to urban composting with High Line gardeners. Participants learned the basics of the science behind composting and different methods of urban composting. They even constructed their own worm bins for easy composting at home.
Sign-up for E-News  to learn more about future composting sessions.