Jesse Horning

Using black plastic to rehabilitate garden beds on a historic city property.

When we purchased our house in August 2022, if we include the lawn, the entirety of the landscape was covered in invasive species and weeds. A few perennial plants persisted among them but it was clear there would be no way to have garden beds of any kind without eradication of the invasive species.

The invasive ground cover species are predominately Hedera helix (English ivy), Vinca major (vinca vine), Pachysandra terminalis (Japanese spurge), and Aegopodium podagraria (Bishop’s weed or ground elder). In this bed shown, all were present except Bishop’s weed.

There are several ways to approach killing an invasive species. Herbicide is a method I was unwilling to try due to ongoing issues with the safe handling of herbicide and the ecological effect herbicides can have on the environment.

Two other common options for killing weeds are cardboard and clear plastic. The process of using clear plastic is called “solarization” whereas black plastic is “occultation”. At a job starting an organic market garden farm, we used clear plastic as the first step in preparing a field for beds. I decided to try black plastic to test the efficacy of it. On this bed, I used black plastic from April 2023 until August of 2024.

In the fourth photo when the plastic has been removed, it is evident how uneven the ground is. In the next photos, note that the vinca vine and English ivy were both dead but the exposed white roots of pachysandra were still showing signs of life. I removed as many of these by hand as I could but anticipate I will have to hand-weed some in the future.

Since our basement has damp issues, likely stemming from broken gutters and negative drainage (water drains towards the house and thus along the foundation instead of being shed away from the house), I took this opportunity to loosen all the soil with a shovel and rake it back to a slope that sheds water away from the foundation. After that, to jump start microbial growth in the soil, I added wheelbarrows of organic vermicompost which I raked into the top 2-3″ of the soil.

On this bed, I used hay as a mulch for the top layer. On other beds, I have used natural wood chips or straw, but after reading Ruth Stout’s book, Gardening Without Work, published in 1961, I decided to try hay. This hay is from Country Max and is the “second cut”, or last season’s hay, and readier to break down and decompose faster than a first cut. (If you’re interested further, here is a YouTube interview and tour with her before her death in 1980.)

Ruth reportedly had excellent results using hay on her vegetable beds, both as a weed suppressant and mulch, so I was curious if it would have the same effect on a flower garden bed. Aesthetically, it leaves much to be desired but my hope is the hay breaking down will reinvigorate the soil that’s been disturbed and by the time I’m ready to plant here, the soil health will be much improved due to the decomposition of hay and leaf litter. This fall, 2024, I will be using leaf litter as much on top of all of my beds to improve the soil health.