Project Highlight: Cardboard Layering Deep Compost Mulch for Weed Suppression, Soil Health, and Profitability
Bindweed can be the bane of farmers’ existence. The climbing vine spreads easily by seed and rigorous root system, choking off crops and other plants along the way.
Annual tilling is not ideal for soil health, and the labor cost of hand weeding is high. What if farmers could find a low-cost, sustainable way to control bindweed by harnessing something as basic as cardboard?
Jonah Sloven, Sweet Hollow Farm, was encouraged by early results of burying cardboard beneath deep layers of compost to keep bindweed at bay. Sloven and his colleagues explored whether cardboard layers can suppress weeds, improve soil health and increase profits.
Cardboard is especially good at suppressing grassy weeds, like crabgrass, by blocking seed banks from the sun. But researchers have suspected that bindweed, with its aggressive, horizontal root system, could make its way through or around a blanket of cardboard.
Sloven at others at Sweet Hollow Farm decided to give it a try. They cleared out the weeds within 30-by-96 feet high tunnel, laid down two layers of cardboard, covered it with a thick layer of compost, and planted tomatoes.
The cardboard biodegraded and the soil beneath it is rich with worm activity, aggregate formation and moisture retention – all signs of soil health. Bindweed is not a problem inside the tunnel. They also found a significant decrease in weed pressure in outdoor plots of squash.
For more information on this project, see sare.org/projects, and search for project number FW22-393.