I just read the article on weed prevention using cornmeal. If I use cornmeal in the fall will it act as a pre-emergent before winter? I live in western Oregon. It just rains a lot here in winter and the weeds slow down, but continue to grow. We don't have much of a freeze, if any. If I understand correctly, treatments are effective for 4 weeks?
Cornmeal as Weed Control
Certified GKH Gardening Expert
The treatment works by preventing weed seed germination, so if you have weeds germinating in the fall, then it can be helpful. University websites state that corn gluten meal is the preferred product over regular cornmeal. These products can be bought in gardening stores or online.
The articles also say that rain will reduce the effectiveness of the treatment, so you may have to re-apply after it rains. It may have a shorter effectiveness period or be less effective in a very wet climate.