Preen is a herbicide that is used to prevent weed seed germination. It will also prevent germination of desired seeds. As the label for Preen advises, the effects last up to three months, so desirable seeds may be planted after that time period.
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Marie Notnats enjoys learning about new topics and teaching people new skills. She has been writing professionally since 2008. She is a professional horticulturist with a Bachelor of Science degree in horticulture from Brigham Young University. She writes for About.com, Examiner.com, eHow, and assorted gardening blogs.