Is Treflan safe for vegetable gardens?

by James
(Opelika, Alabama)

The man at the seed store told us that treflan is a safe weed killer for vegetable gardens. We bought some but I want a second opinion before I use it.
Thank You,
James Baker

Doug says - let's start at the beginning.

Treflan is produced by Dow and their website says, "Treflan delivers economical pre-emergent, season long control of grassy and broadleaf weeds. It is a selective liquid herbicide for pre-plant soil incorporated weed control in many field crops, vegetables and ornamentals."

This means you put it on before you plant or the perennial crop starts to grow and it will stop weeds all summer long.

Now - let's look a little deeper. All this data is coming from the label or the msds (safety) sheet that has to be included in this product by law. It is not my opinion - I'm quoting.


The label (mandated by law) says, that applicators *must* wear protective clothing including chemical resistant gloves, protective eyewear and long sleeved shirts, pants and protective footwear. You have to invest in safety equipment to use this product (and you want to - see medical conditions below)

If used commercially, there are required safety courses that must be taken.

There are required no-entry periods of 12 hours (in other words, if you put this on your garden, you can't go on your garden for 12 hours afterwards)>

Sound safe yet?

What about how long it stays in the soil. There are some crops that can't be planted there for 12-14 months. So it is persistent - in my books, this clearly means it isn't organic or something I'd want to work with in digging, harvesting or eating plants grown in it.


What about using it on perennial vegetable crops like asparagus? Well, if you miss the exact timing, the crop is not able to be eaten because of residues in the asparagus.

What kind of soil do you have? Coarse, medium or fine soils? The rate of application depends on the kind of soil you have and the crop you're trying to grow. One size does NOT fit all. In other words, one application rate might be OK for one crop on one soil but it has to change for a different crop on the same soil.

What about medical consequences? Well, the label also says that if you have any skin contact with this product you are to "seek medical attention". So get some on your skin from mixing and/or spraying with spray drift and you earn yourself a trip to the emergency department. Ditto for breathing or getting spray drift in eyes (hence the need for goggles)

Is it effective? Well, that depends on the soil, the crop, the timing of application, and the weather (cool temperatures versus hot temperatures). In other words, if applied properly at the recommended rate for the soil and the weather is right - it stops the target plants. Get one of these things off and your results will vary.

Safe yet?

I could go on. Let me point out that all this data is from the label of the product. It is not from any organic website or opinion of mine. And I didn't even go into toxnet at Cornell University (another government research area outlining environmental testing/concerns) I'm simply looking at the hard data that has to be presented as part of the labelling process. And let me tell you that there are organic "opinions" on the web that are not complimentary to this product. :-)

Bottom line (if you haven't guessed it yet) is that this is something I wouldn't want in my garden. Do you want to apply something that is going to be in your soil for at least a year, can't be touched without a trip to the doctor, may poison your plants if used improperly on some crops, and depends on soil conditions and weather for effectiveness?

I use mulch to stop weeds rather than chemicals. Non-chemical, easier to apply, works in all weather and enriches the soil.