I used Preen in my flower garden with great success. Would it be safe to use in my vegetable garden? Just what is Preen made of?
Preen use in the vegetable garden
Here's the information on the manufacturer's website: http://www.ams.usda.gov/AMSv1.0/ams.fetchTemplateData.do?template=TemplateN&navID=NationalListLinkNOPNationalOrganicProgramHome&rightNav1=NationalListLinkNOPNationalOrganicProgramHome&topNav=&leftNav=&page=NOPNationalList&resultType=&acct=nopgeninfo Sounds like it is hazardous to just about every living thing.
The active ingredient for the product you most likely have is trifluralin. Here's a link with information on that substance's toxicity: http://www.scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=1582-09-8
You can either spray poison in your garden and kill the organisms that would've contributed to its health and success, or you can mulch with organic materials such as shredded leaves, non-chemically treated grass clippings, wood chips, . . . and improve the quality of the soil and support the organisms that live in it.
Out in the Ag world it's called Treflan. It was used in soybeans as a pre-plant to control grass. Use has diminished since the use of Round UP ready bean seed.
Preen in the vegetable garden is deemed safe by the manufacturer. However, they don't give you the whole story. It is a slow breakdown chemical, so after a number of years use, most crops will suffer it's effects. It will kill corn because corn is a grass. Vine crops hate chemicals. You will be wondering what is wrong with your melons & cucumbers as they are dying off. Then you will spray them with everything you can think of for blight, powdery mildew, etc. All along it's Preen damage.
Flower gardens, cypress mulch works really well. It does not use up nitrogen like other organic mulches & stays put for a long time. It looks good. 3" deep or so is all you need. Each spring I go around & renew any thin spots.
This past summer I had no time to care for my large cottage garden. Hardly even looked at it. It is mulched completely with cypress. Very few weeds were present. I will be tearing it up & replanting many things this spring. My pond is going to now be a water feature, so lots of plants need to be moved. Also built onto the house this fall & some things are now to close.
In our vegetable garden, we make use of plastic mulch & mechanical cultivating. Also have a couple people doing hand weeding. I realize you can't hire weeders for a home garden, but with a little imagination, you can beat the weeds.
Bernie
Interesting, Bernie. I always wondered how something like that could know the difference between weeds and the rest. I guess it doesn't!
My first year gardening, I used a mulch that I think was cypress. It was really nice-looking, whatever it was. Then I read that cypress mulch isn't sustainable. Big sigh.
This year, I made some walking paths through my garden with cedar mulch. I think it probably stopped the slugs from moving from my brother's adjacent strawberry patch to my garden - a happy accident. Any truth to the idea that it repels insects? I thought about experimenting by putting a ring of it around the squashes to see if that would bother the squash vine borer. But I wouldn't want to discourage the beneficials, which I had in great supply.
In place of Preen one could use Corn Gluten Meal in the vegetable garden. It does not kill weeds but supposedly helps prevent weed seeds from sprouting. It obviously should not be used where one is planting veggie seeds to sprout or it would inhibit those as well. It can be used after the veggie plants are up and strong. It is an organic and safe product. I believe it needs to be applied several times in the seasons to be effective since different weeds emerge at different times. I got mine from Garden's Alive but have not used it that much anywhere. I'm a glutton for weeding, I guess, and heavy remulching! If you google corn gluten meal weed killer a number of organic sites will come up. Many are not on Garden Watchdog but have the product. I can heartily recommend Fedco (http://www.fedcoseeds.com/ogs/OGSorderItem.php?id=8797&listname=Corn), the Organic Growers Supply subsidiary, as being reliable. I got mine a few years ago from Garden's Alive but they get very mixed reviews.
This message was edited Jan 1, 2010 5:42 PM
This critter liked my mulch (and bugs!), too.
We have lots of toads here.
Why isn't cypress mulch sustainable ? Any other wood based mulch uses up the fertility of the soil to break it down. Some woods like black walnut will actually kill your plants.
My understanding of the cypress sustainability issue is that since it makes such an attractive and long lasting mulch that demand has increased to the point that there is a lot of tree cutting going on. They are taking the old growth trees and affecting the ecology of the swamps and wetlands.
Cypress is slow growing and the extensive root systems are vital for holding soil, slowing moving flood water and providing habitat. Wetland preservation is important for filtering all our nasty runoff to keep our streams and oceans clean and to nurture our fisheries. And so it goes...right on up the supply chain. We rant against other countries cutting their rain forest and here we are doing the same thing.
Pine bark is a good affordable alternative. It's an abundant by-product from the timber industry and they grow much faster.
On the issue of degrading bark robbing the soil of nitrogen...I've read that many times but I don't see it in practice. I've grown lots of daylilies in 100% pine bark and it degrades to look almost identical to peat. I recycle it by mixing it with new and old potting soil. Sometimes I just add fresh bark to the old. I can't tell any difference in performance or fertilization needs.
I think we can all agree that compost is a fertile soil conditioner. It's broken down by the same process as bark. I would call decomposed bark a single crop compost that adds rather than detracting from fertility. Of course everything is relative and my soil is really about the equivalent of beach sand so it probably doesn't have any nitrogen to start with.
I'm getting ever closer to the edge because I've taken to reciting "dust to dust" anytime anybody wants to trash some sort of organic matter. It's all good stuff, except walnut trees.
I listened to a story on NPR this summer about cypress mulch and the sustainability of it. I won't be using it anytime soon after what I heard. I can't remember specifics but I know some big companies were not telling the truth about their harvesting methods. These companies supplied big box stores most of the time.
I guess the best advice is to look into each brand.
I'm sure there are a few good sources out there though who harvest sustainably.
That makes sense about the cypress. I've never used pine bark. I have used pine sawdust & it literally killed the plants it was around. I also had a couple of loads of tree trimmings from an outfit that trimmed power lines. Mulched my flower beds with it, & the plant quit growing & turned yellow. Raked all the mulch off & after a while they finally looked a bit better. Some never came out of it.
As long as they sell the cypress I'll be using it. Won't need much now as all beds are mulched and will only have to amend it.
We have extremely good soil here, so don't need to add compost. Most people could use our soil as compost.
Out in our market garden, all the old plant material is chopped & plowed into the soil. We never rake leaves or remove grass clippings off the lawn. Don't fertilize it or spray for weeds either. Our lawn is green all season even if it gets dry.
Night crawlers abound here. Some mornings the little piles they leave during the night are almost a solid mass. Maybe 25 or so to a sq ft.
Bernie
Sounds really amazing Bernie! I have one little spot in my yard that has beautiful soil. the rest is very sandy.