April 27th 2023
By guest blogger Brian Koehler
Inspired by the process of achieving CBLP Level 1 certification, I received permission to implement a small turf reduction project on the Pennsylvania Recreation and Park Society (PRPS) office property as a sample bio-swale for others in the industry. The project began in the Summer of 2021 and the bulk of installation work continued through the Fall until the first hard frost. The following details outline the steps I went through in completing this project. A brief photo montage capturing steps can also be found here.
Site Selection
The area chosen for this project was previously designed as a turfgrass stormwater swale, capturing runoff from the adjacent parking area. However, it was a challenging area to safely maintain with commercial mowers. Landscapers would often scalp the grass too short or bottom-out with the mower deck, consistently leaving damage. Choosing to replace turfgrass with a rain garden reduced landscaping challenges while improving habitat diversity and site aesthetics.
Kill Existing Turfgrass
Due to a lack of proper equipment, tilling of the area or mechanical removal of turfgrass were not options. Rather than using non-selective herbicide to kill off existing growth, I chose to smother the grass by sheet mulching the entire site. This decision opened up the project to community engagement. Local businesses like appliance stores, grocery stores, and pet stores were happy to help save big boxes. Managers were excited to know the cardboard waste from their weekly deliveries went towards a sustainable project.
Covering the Base and Managing Water
The cardboard base was covered by a 4-inch layer of 50/50 mixed topsoil and mushroom compost. Next, I incorporated river stone, pea gravel, and sand along the paved edge to create a forebay and reduce erosion from stormwater run-off.
Planting Plugs and Seed Broadcasting
To begin, I planted a mix of perennial grasses, shrubs, and native wildflowers. I used a bulb auger to ensure I broke through the cardboard barrier and planted plugs directly into the native soil layer.
My primary objective was to add plants that attract pollinators and have deep roots in sunny areas. I chose a variety of ferns and a mix of native and non-native perennial species to fill in the shaded spaces. I continued to broadcast seeds throughout the growing season by “deadheading” flowers each week.
Seasonal Maintenance Lessons Learned
I monitored stormwater carefully throughout the Winter and into early-Spring. Since this was my first project design, I was slightly concerned that the BMP might fail due to an increased soil depth. However, I was pleasantly surprised to watch runoff follow its intended pathway and easily infiltrate into the ground within a matter of hours.
As the surfacing settled, maintenance included the addition of more material and the repair of erosion ruts after heavy rainfalls. Once snow began to fall, it was important to consistently remind landscapers to refrain from plowing directly into the BMP area, since that was a location where snow piles were historically deposited.
Next Steps
The success of this initial project piqued interest to reduce turfgrass areas even more on the property. I started another project at the end of Summer 2022, by sheet mulching a heavily shaded area. This area is even challenging for turfgrass to grow and is frequently damaged by landscapers spinning wheels. The intent is to densely plant this area with fern and perennial bunch grasses to fill the space, diversify the habitat, and improve stormwater infiltration.
My hope in sharing this experience is for readers to gain an appreciation that turf reduction efforts do not necessarily require consultants, architectural drawings, or master plans. Sometimes the simplest answers reveal themselves when the initial effort is made. If you would like to learn about more ideas for “pocket projects” that could be implemented with a group of ambitious volunteers in a day, reach out to me for a chat. bk@prps.org
Brian “BK” Koehler has been the director of The Maintenance Institute in State College, PA, since early 2020. He is an experienced facilitator and event professional with a background in teambuilding, rope course construction, and outdoor leadership. Before joining the Institute, BK worked internationally as an experiential educator, producer, facility manager, and entrepreneur.
