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Gardening Answers Knowledgebase

Plant Answer Line Question

Keywords: genetically modified seeds, Weed control, Herbicides

What can you tell me about the weed killer "Concern Weed Prevention Plus"?


This product is corn-gluten based, and it is not meant to work on weeds which are already growing, but on those which have yet to emerge (pre-emergent). Corn gluten meal has been promoted as an environmentally safer alternative to conventional herbicides, but there are still certain issues that bear considering. Research at Oregon State University showed that corn gluten meal did not prevent weed seed germination. Here is an excerpt from the study's findings:
"Corn gluten meal did not control any weeds in any trials under any circumstances over a two-year period. They found no evidence of pre- or post-emergence weed control in any of their trials. Because it contains 10 percent nitrogen, corn gluten meal proved to be a very effective fertilizer, causing lush, dense growth of turfgrass and of weeds in shrub beds."

Although corn gluten meal presents far fewer risks to human and animal health than conventional herbicide, a gardener who is attempting to use only organic methods might consider the source of the corn in these products, which is very likely to be genetically modified. A webpage no longer available from University of Wisconsin Master Gardeners addressed this question:
"Up to 60% of the commercial corn and soybeans in the United States is grown from GMO seed. Corn gluten sold as a preemergent herbicide may indeed contain GMO corn, but it has not yet been tested. Here's the twist. Corn gluten can reduce the need for traditional herbicides that have environmental side effects. It likely now contains GMO corn. It could be produced from non-GMO corn, but would likely be more expensive."

Washington State University professor of horticulture Linda Chalker-Scott has also written about "The Myth of Weed-Killing Gluten," and states that no research suggests this is an effective method of weed control in the Northwest. She recommends sub-irrigation, mulch, and soil solarization instead.

Date 2017-05-04
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Plant Answer Line Question

Keywords: genetically modified seeds, Organic gardening, Seeds

I read an article recently that said some of my favorite seed companies are now owned by Monsanto. I don't want to use genetically modified seeds in my home garden, so I'd like to know where I can find more information on the sources seed companies use for the seed I am buying.


You may be referring to the January 2009 issue of the PCC Newsletter regarding Monsanto purchasing many of your favorite garden and farm seed catalogs. Territorial Seeds, Johnny's Seeds, Park Seed, Burpee, Cook's Garden, Spring Hill Nurseries, Flower of the Month Club, and Audubon Workshop are not owned by Monsanto or Seminis. PCC subsequently posted a retraction.

The folks at Organic Seed Alliance are a great resource on this issue. Here is what they suggest:
"For gardeners interested in buying non-GMO seeds, the best bet is to purchase seeds from seed companies who sell only organic seeds and who have signed the Safe Seed Pledge."

For further reading on the subject, see this February 2005 article by Matthew Dillon from the Rodale Institute on Monsanto's purchase of Seminis. Environmental News Network also has information about a September 2008 discussion forum with writer Michael Pollan and Monsanto CEO Hugh Grant.

Date 2017-12-08
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May 31 2018 13:14:08