Using Preen in vegetable beds

10 years ago

Two questions about using Preen.

Every year I mulch my vegetable beds with straw and always end up with weeds in my beds. So this year I thought maybe I’ll mulch with straw and then apply Preen to prevent weed seeds from sprouting. But then I googled this and read that Preen might stunt the growth of existing plants. Preen won’t kill them but the growth will be slow. Obviously I don’t want that to happen to my veggies. Anybody experienced this?

I planted my Dahlia tubers and then applied Preen to that bed. Nothing has emerged yet. Will Preen prevent Dahlias from sprouting? I was thinking since Dahlias are not seeds they won’t be troubled by Preen. What do you think? Appreciate your input.

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rhizo_1 (North AL) zone 7

10 years ago

last modified: 10 years ago

I think that Dave is mistaking Preen with another herbicide. It IS recommended for use in veggie gardens; it is NOT absorbed systemically by established plants. It creates a barrier in the soil, when adequately watered in, that prevents newly germinating seeds from growing roots.

When applied at the right time, it should have no effect on young but established plants. You can use Preen with established dahlias and other bulbs and tubers.

Suzu, all of the correct information is on the label. You can find labels online or on the product itself. Sit down and read the information; it's not complicated.

That being said, I don't use Preen in my vegetable garden as a personal choice. I have used it upon occasion in my annual and perennial beds in the past, with no ill effects...after planting but before applying my couple of inches of mulch.

Again....read the label and don't apply it until you fully understand how much to use, how to apply water afterwards, how the barrier works, when to use it with your established plants, that you should stay off of the soil afterwards to avoid disruption of the barrier, etc.

Preen can, according to the label, be reapplied as needed, even up to the day of harvest.

My preferred method of weed control in my veggie garden, especially, is a long handled hoe! Eeek. I would never apply anymore than two or three inches of mulch....in my clayey based soil, that would have a smothering effect.

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Comments (10)

digdirt2
10 years ago
Can't comment on dahlias but the use of Preen has been discussed here many times and if I recall correctly others have posted that the label instructions specify weeks in advance application before planting. Otherwise its use is not recommended in vegetable gardens just for the reasons you mention - stunting. Plus it is systemically absorbed by the plants. Do you want Preen ingredients in your vegetables?

The weed seed sprouting for straw indicates that the mulch has not been applied thickly enough to be effective. A minimum of 4-6" deep with 8" deep is commonly recommended.

Dave
Susu
Original Author
10 years ago
Thanks Dave. I just read your comment about mulch to another poster. Will add to the layer I have. Hopefully that'll keep weed at bay.

Hope somebody comments about dahlias. Because I've already applied preen to that bed. Can't redo it. But hoping to see if I have to do any damage control and remove the soil layer with preen.
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digdirt2
10 years ago
"Hope somebody comments about dahlias."

These are bulbs correct? If so then there should be instructions on the label for its use with bulbs.

Preen label

lists dahlias and specifically says "around established plants only". It always pays to read the label before applying anything.

Dave
Susu
Original Author
10 years ago
Ok I got some damage controlling to do :)
digdirt2
10 years ago
Yep the label tells it all which is why I went to the label and linked it above. Active ingredient is Trifluralin and plenty of info available on it online. It is an emulsifiable ingredient (water soluble so can be taken up by the plants) and toxic to all aquatic life if water is contaminated with it. A hoe and hands are much less toxic. :-)

http://pan-uk.org/pestnews/Actives/Triflura.htm
LoneJack Zn 6a, KC
10 years ago
last modified: 10 years ago
A much less toxic albeit less effective alternative to Preen would be Corn Gluten Meal (Organic Preen). I have used it on onion and garlic beds in the past and it has the added benefit of nitrogen (9-0-0 I believe). It does not have any negative effect on already growing plants.
Peter (6b SE NY)
10 years ago
I thought Preen was corn gluten meal... I guess not. Does it come in different formulations?
LoneJack Zn 6a, KC
10 years ago
The original Preen is Trifluralin as Dave mentioned. A few years back they came out with the Organic Preen which is Corn Gluten meal. Corn Gluten meal has been around for ages but in the last few years has more than doubled in price to nearly a $1/lb. ( if purchased in 50 lb. bag) due to the organic movement. I picked up a 50 lb. bag 4 years ago and still have a little left.
HighColdDesert
10 years ago
I hope it works out for you this year. For next year, you could try a simple physical barrier tactic rather than a chemical one, and lay down cardboard or newspaper before laying down the straw. Just make sure to leave a gap in the barrier layer where your desired plants have to get through. If due to good moisture, some weed seeds still germinate in the straw, they will have trouble reaching soil, and you can just jiggle the straw layer to disturb their roots without even really pulling them up, and they'll die.