Hello there~ I would be interested in what people have to say about this too. I have been using Preen for a few years now. It works very well for me, I was also told to put it on later in the fall to control winter weeds. I still try not to use chemicals if I can but my joints are yelling at me all the time anymore. I have always wonder about long term use?? Thanks Debbie

The active ingredient in Preen is trifluralin. It works by affecting seedling root growth. It doesn't stop germination, but does keep the seedling from establishing.You can find some information at this link. Soil incorporation by watering in the product or by mechanical means is essential if the product is to work. Preen works fairly well on grasses when used as directed, but is not very good for some of the broadleaf weeds. The active ingredient is very toxic to fish, which is why it should not be used near waterways.

Here is a link that might be useful: Extoxnet

You could try corn gluten.
http://www.ipm.iastate.edu/ipm/hortnews/1997/6-20-1997/cornglut.html

My father is elderly (91) and no longer able to keep up with the demands of a rather high-maintenance yard. A number of his shrubs and flower beds are overrun with cheat grass. Will Preen Weed & Grass help to control cheat grass? Any advice will be much appreciated.

A much easier and cheaper means of weed control is a good mulch, although that will not stop invasive grasses, but then little or nothing except a good, solid barrier between the planting bed and grass will either.
Preen does not add anything beneficial to your soil, as mulch does,
Preen will not aid in retaining soil moisture, as mulch will.
Preen will not aid in keeping your soil cooler, as muclh will.

A good landscape cloth, covered with mulch would be better. Don't poison yourself by putting that stuff in your yard.

LOL!! Preen is not exactly going to poison you :-) In fact, its toxicity rating is very low. Just don't allow it to leach into waterways, as it does have toxicity for aquatic life.

And landscape fabric/weed cloth is generally recognized as having minimal effect on controlling weeds plus being an impediment to proper watering and fertilizing. And it it almost impossible for self seeders to get established or to accommodate new plantings. Mulch alone will work just as well and without any of the landscape fabric drawbacks.

Same thing the army said about Agent Orange. It doesn't have to kill you, just damage nerves, cause cancer.

I'm a fan of landscape cloth. I struggled with morning glory for years. Roundup doesn't kill it. Only putting landscape cloth over, covered with mulch stopped it. Landscape cloth does have it's inconvenient drawbacks, but I could not have established self-seeders to grow with the bindweed problem anyway. It's very effective at stopping weeds. Some weeds will grow in the mulch, and they need to be pulled, but it's minimal.

YOU may be a fan of landscape cloth but if you review these forums, you will find overwhelmingly negative remarks about the stuff. It is not at all effective for weed control and if you do a Google search under those terms, you will find this negative opinion is shared by a whole lot of other, non-GW gardeners, both home and professional.

And there appears to be some serious misunderstandings about herbicides and
how they work..........comparing Preen to Agent Orange is preposterous. That's like comparing apples to chickens (even further removed than oranges). Other than they are both edible, there is no similarity

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0101186

Preen for vegetable gardens is corn gluten meal.( Safe)

Regular preen has 2 4 d which is in agent orange and is a highly suspected carcinogenic.

We should note that mulching, for an elderly person, is just as difficult as weeding. And those bags are heavy!

Regular Preen does NOT contain 2,4-d. The active ingredient is trifluralin.

btw, 2, 4-d is an ingredient in almost all lawn weed and feed products and broadleaf lawn weed killers. It is the dioxins contained in Agent Orange that are the most toxic component of that herbicide and they are primary found in the other active ingredient, not the 2,4-d.

"Trifluralin is the active ingredient in this type of Preen product. The chemical is extremely toxic to aquatic creatures such as fish, oysters and shrimp, as well as to amphibians. It may also be harmful to honeybees."

The preen lawn care product lists 2 4d as an ingrediedient. It is a highly suspected carcinogen.. and part of the toxic soup, agent orange.The preen for vegetable gardens contains corn gluten meal, safer alternative for humans and fauna