Newly Registered
Posts: 5
Joined: Mon Sep 06, 2010 7:25 pm
Location: Ohio

Can I use Preen and still be organic?

Can I put Preen down to try to prevent weed growth and yet still be organic? If not, what is an organic way to keep weeds under control?
Mason, Ohio

User avatar
Green Thumb
Posts: 319
Joined: Fri Jun 04, 2010 9:17 pm
Location: Western MA

Preen is mostly corn gluten, which is considered organic. There are, however, different types. One is for vegetable gardens and, looking at the MSDS, doesn't contain harmful additives. The other is for "gardens" (I guess this means flower beds?) and is not considered organic.

That said, even the first one has a warning about preventing contamination of ponds, streams, etc. As soon as I see things like that, I tend to shy away. I'm also not sure, based on the label notes (available online) if it kills all weeds, or just the select few listed. I'd check which weeds you're trying to prevent before using it. Further, it works by killing seedlings, so if you're planning on direct sowing, I'd use caution there, too.

The most "organic" ways of preventing weeds are hand-pulling and mulching. And keep weeds from spreading by pulling and/or cutting before they go to seed.

Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

Reading the label for Preen online, it appears that this product is toxic to aquatic forms of life and should not be allowed anywhere near storm drains.

Its active ingredient is trifluralin (1.5%, more or less) and "inert" and unnamed ingredients comprise the remaining 98.5% of this compound. A search on trifluralin shows that it is suspected of being an endocrine disrupter in people; not good news.

There are many weed-suppression approaches endorsed by members of this forum, and it often depends upon which weeds are the pain in the yard: deep-rooted? shallow-rooted?

Most of what I deal with are tap-rooted weeds, so I dig them out with a "weed stick," which others also call a dandelion fork, asparagus knife, or fishtail. I've conquered Yellow Star Thistle, redstem filaree, burclover, and dandelions in my (admittedly small) garden/yard.

If you look under "Search the Forum" for "weed management" or "weed control," you'll find lots of help from people who live closer to you and who are dealing with the suite of weeds you are.

Happy gardening, and much success in rooting out those weeds.

Cynthia H.
Sunset Zone 17, USDA Zone 9

Return to “Organic Gardening Forum”