Is it safe to eat dandelions previously treated with a selective iron herbicide?

Question

Three years ago, I started trying to reduce the number of dandelions in my lawn with a household selective herbicide named Scotts® EcoSense® Weed B Gon® (MSDS and retailer product page). The manufacturer's web site says:

Weed B Gon controls dandelions and other broadleaf weeds without harming the grass. It is made from iron, an ingredient found in the natural environment.

The last time I treated the lawn with Ecosense Weed B Gon was about one year ago. I still have all the dandelions, but this year my wife has said that she wants to try making food products from the dandelion roots in our lawn (examples of dandelion foodstuffs).

Is it safe to consume dandelions from a lawn previously treated with a household selective iron herbicide?

Answer 1

It is difficult to answer the question of whether or not it is safe to eat dandelions or other plants that have been treated with this herbicide. You'd have to know how much iron the plant has actually absorbed in the part you intend to eat and whether that amount of iron would harm you.

The main ingredient is chelated iron. Chelated iron is sometimes recommended to take orally to treat anemia but there are risks and side effects. See http://www.webmd.com/drugs/drug-60389-Chelated+Iron+Oral.aspx?drugid=60389&drugname=Chelated+Iron+Oral

There are other ingredients in the product that are not listed further making it difficult to asses safety.

This product is not OMRI listed but other chelated iron products are for the purpose of treating plants that have an iron deficiency. I have not seen one listed that is intended for use as a weed killer. I would assume the dosage/concentration would be higher for killing weeds.

Your best bet would be to contact that manufacturer and see what they have to say. Considering this product is intended for use on lawns to kill weeds and not for food crops they're probably going to err on the safe side and tell you it's not intended to be used on plants you plan to consume. Even though this product appears to be safer than traditional Weed B Gon I would also advise to err on the safe side and not consume any plants that have been treated with it.