Corn gluten meal (CGM) has been getting some press on and off the past few years as an alternative to using regular weeds and/or feed products on the lawn.
There is some interesting data that have been now gathered, according to tests that were taken at the UMORE Park which was also part of the Master Gardener Education Research and Display garden.
Bob Mugass, Brian Horgan and Andrew Hollman took this information and put it together for us so we each can decide what kind of preventative steps we want to take with our own lawns.
This information is listed here.
All study plots, including the controls, were free of any annual weedy grass invasion. Therefore no additional information can be provided regarding CGMs effects on controlling warm season annual grasses such as crabgrass. However, the immediate surrounding area had very high dandelion populations.
Hence, these served as a good source for wind blown seed into the study plots and enabled assessment of CGMs effectiveness at preventing dandelion invasion into what were initially weed free plots.
May-June and May-August-October treatments remained at or above minimally acceptable lawn color quality on nine of the twelve rating dates and eight of the twelve rating dates for the May-August treatment. In only two instances were there significant differences noted between these three treatments.
The May-only and October-only treatments showed significantly better color than controls on eight and three dates, respectively.
In the October-only treatments, two of those better times were the spring green-up ratings. May-only and October-only treatments were at or above the minimally acceptable lawn color rating on only four and two dates, respectively.
While plots receiving two or three applications per year had less dandelion cover present than the controls or single applications, percent dandelion cover steadily increased over the course of the study regardless of treatments.
During the season, significant differences in percent weed cover were noted among the two mowing heights. In all cases, the 3.0 inch height had significantly fewer dandelions present than the lower 1.5 inch mowing height. Average dandelion cover continued to increase from 28.1 percent in April to 43.3 percent in October in the higher heights of cut.
While the data did show a significant difference in percent dandelion cover between the higher and lower mowing heights over the 2005 season, this amount of dandelion cover would often still be considered unacceptable in home lawns. "
In conclusion to the above referenced results this is what we know about the application and usefulness of CGM on our lawns. "A minimum of two CGM applications annually is needed to provide minimally acceptable lawn color throughout the growing season. Under the non-irrigated conditions at this location, there was color loss across all treatments during hot dry periods.
"Spring green-up from late October applications is very good with average or better color retained through May and into the early June growing season.
"Regardless of corn gluten meal treatment or different mowing heights, there was unacceptable dandelion control, at least for home lawn situations, over the four years of this study."
Corn Gluten meal is becoming more widely available. There is a Preen product that contains Corn Gluten meal; you will need to read the label carefully since there are several kinds of Preen.
And, yes we now have a professional lawn care company locally that can also assist you with using this product on your lawn.
For more information about gardening, you can email me at firstname.lastname@example.org