PROSSER, Wash. — Commercial flower and plant growers know all too well that invasive, ubiquitous weeds cause trouble by lowering the value and deterring healthy growth of potted ornamental plants.
To control weeds, many commercial nursery owners resort to the expensive practice of paying workers to hand-weed containers. Some growers use herbicides, but efficacy of herbicides is questionable on the wide range of plant species produced in nurseries, and many herbicides are not registered for use in greenhouses.
Enter “dried distillers grains with solubles”, or DDGS.
DDGS, a byproduct of converting corn to fuel ethanol, is typically used as livestock feed. USDA’s Rick A. Boydston, Harold P. Collins, and Steve Vaughn researched the use of DDGS as a weed deterrent on potted ornamentals.
They applied DDGS two ways: to the soil surface, and mixed into the potting media of transplanted ornamentals.
Applied to the soil surface after transplanting, DDGS caused no injury to plants. According to Boydston, an agronomist with the USDA’s Agricultural Research Service, “grains applied to the surface at rates that gave good coverage of the soil (800 and 1600 g/m2) reduced the number of common chickweed and annual bluegrass. Weed control was not perfect, but could reduce the amount of hand-weeding typically required.”
When mixed into the potting media, however, dried distillers grains were toxic to transplanted rose, coreopsis, and phlox plants.
Researchers concluded DDGS may be useful for reducing weed emergence and growth in container-grown ornamentals when applied to the soil surface at transplanting.
Dried distillers grains are becoming more readily available as ethanol production in the U.S. increases.
The push to produce ethanol, a cleaner-burning alternative to gasoline, has gained interest as gasoline prices continue to soar. As production increases, finding new uses for byproducts like DDGS becomes more critical.