Site Prep With Used Billboards
Solarization, tarping or occultation are good methods for site preparation for native seeding and planting. But what about all that plastic! It’s hard to say you’re doing something to benefit ecological function when you consider the amount of fossil fuels that go into manufacturing the plastic sheeting or tarps needed for solarization, tarping or occultation, not to mention the persistent and growing problem of microplastics in the environment. One solution is to repurpose old vinyl billboards for this purpose. Using old billboards repurposes something that would otherwise end up in the landfill. The following two sites offer used billboards: Billboard vinyls and Billboard tarps.
By “up-cycling” this material, we have kept millions of pounds of material from heading straight to landfills.
-Billboard Tarps
Vinyl billboards are made to be used outdoors along roads and highways and to withstand harsh weather conditions. They are made of UV-protected and water resistant vinyl layers, with rip-stop nylon between the layers to prevent tearing. If you live in an area with lots of deer, this can be important. Deer and people can walk on this material and not tear it. It is durable for rural or high traffic areas.
Used billboards come in a wide variety of sizes. You can get white on one side, with the old ad on the other side, or black on one side with the ad on the other side — we prefer to use the used billboards with the black side on the back.
The used billboards are installed for site prep, with the advertisement side down, and the black side up, helping to control weeds over the summer before sowing native seeds in the fall. They must be kept in place for at least six weeks or longer, depending on the tenacity of the underlying vegetation. The longer the billboards are in place, the better.
The repurposed billboard is relatively heavy on its own, but you can use rocks, sandbags, bricks or other heavy objects to weigh down the edges.
Using old billboards is technically a form of occultation. Occultation is similar to solarization, but opaque coverings are used instead of clear. Black plastic actually absorbs light, and takes longer than solarization with clear plastic, which allows light and heat to penetrate. In some situation solarization with clear plastic may be a better option, depending on the current vegetation on site and the what weed seeds are present in the soil seed bank. Billboards can be reused over and over; whereas, clear plastic tends not to last as long and is more prone to tears.
We personally used an old billboard, with a jewelry ad on one side and black on the other side, to tarp an area where we had recently cut out non-native lilacs that had grown on our property since before we bought it. We’ve left the billboard in place over the summer, and without sunlight the lilacs have not been able to grow more than a few, spindly, blanched stems. It’s easier than digging it out, and preps the overall area well for native seeding by eliminating the competition and creating a nice, open area with exposed soil.
When not using old billboards for site preparation for native seeding or planting, they can also be repurposed and used like a tarp for other applications where a waterproof tarp is needed. Ideally vinyl billboards will be replaced by a more eco-friendly product in the future for advertising, but until then, and while there are, unfortunately, lots of them in the world, we might as well put the used ones to use for aiding native seeding and planting projects, and prevent them from immediately entering the landfill after just a few month’s use.
*Note: Tarping, or occultation does not effectively control field bindweed (Convolvulus arvensi). Other techniques must be used to control this specific species — yeah, don’t we know it, bindweed is difficult!