Persistent Herbicides Lead to Home Garden Troubles

I got a call last week from a gardener whom I really respect.

He is a good steward of the soil and of natural resources, and he shares his knowledge with the community at large–teaching other people how to grow food, how to compost effectively, and about the life of the soil.  When he does research, he really “goes to Earth”–rooting out information and following leads like a terrier after a rodent.

My friend was distressed because he was seeing some problems in his gardens that he had never seen before–starting earlier this spring with the sudden death of tomato plants he started from seed, and continuing with curled, deformed, and mottled leaves on a variety of different crops during this growing season.

Mottling on Bean Leaves

In his research on the problems he was experiencing, he learned about a class of herbicides that has come into broad use for grass pasture because of their effectiveness against Canada thistle (a pernicious weed I am all too familiar with myself).

These herbicides, many of them called aminopyralids, persist in pastures grown for grazing and hay production, and also in the digestive tracts of animals fed grass hay from these pastures.

There is an excellent article (pdf!) by the North Carolina Cooperative Extension on these herbicides that discusses their persistence and the need to communicate with hay buyers and gardeners about their use.

In my friend’s case, discovering a possible source of the problem led him on a path from his damaged crops, to the manure he used, to his friend’s horses, to the pasture owner who sold the hay, to the contractor hired to spray those fields.

Curled and Malformed Leaves on Squash Plants

When the manure from animals fed grass hay from pastures sprayed with these types of herbicides is spread in vegetable gardens, the very kinds of problems my friend is experiencing can result–whether or not that manure was composted before use.  Damage can also result from using contaminated hay, straw, or grass clippings.

One of the most-read articles on my blog is one on Leaf Roll and Curl on Tomatoes and Potatoes.  That post discussed moisture stress issues, and how it can cause leaves of these plants to curl up.

Leaf Curl on Volunteer Tomato

After having seen my friend’s garden, I began to wonder if those searching for a reason for problems in their gardens might be experiencing something quite different–residual effects of herbicides used on the compost, grass, and/or hay they’ve used as mulch of fertilizer in their gardens.

After doing some of my own research, I have learned from County Extension agents that some of the same persistent herbicides are now being marketed toward homeowners for lawn care.  Your county weed board may also be spraying these chemicals on ditch hay–check the source of any compost, manure, hay, grass, or straw you bring into your garden or onto your farm!

The Garden Organic site has more information on this topic and lists of the market names of herbicides, as well as what to do if you suspect that your garden has been contaminated with these chemicals.

In addition, my friend is seeking additional input in his research on aminopyralids, and asked me to share the following statement:

“Dean Spader believes Dow’s ForeFront with its aminopyralid herbicide was the main cause that completely destroyed his young heirloom tomato plants.  If you wish to contact him for more information, you can call him at 605-624-6831.

In case you’re wondering, Dow does not deny that its herbicides have caused problems in gardens and on allotments (in the U.K. at least).  The lesson here is to protect yourself and your (and your neighbor’s) food supply and do your homework on any inputs you use in your garden, on your lawn, and on your farm and fields.

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6 responses

  1. Pingback: Persistent Herbicides Lead to Home Garden Troubles (via Flying Tomato Farms) | Between Leaf and Sky

  2. I spread some manure a few weeks ago. I got it where people empty out
    their horse trailers. My tomato plants were
    looking fine–though we’ve had a cool summer and they weren’t growing
    really quickly. Then I noticed most of the leaves had curled up tightly.

    I looked it up online, and I’m almost certain that it’s from the manure. I
    also have a rose that lost all of its leaves though the flowers and buds
    are intact. My question is can one remove the manure? Can the plants
    recover? Can one eat the vegetables if they do recover–obviously they
    won’t be organic anymore?

    • If you top-spread the manure, you could shovel it out of there. In response to your other questions–I really don’t know if they will recover. The rose might, but tomatoes are very susceptible to broadleaf herbicide damage–a dressing of fish/seaweed emulsion or something similar *might* help. Your call on whether to eat the fruit should they recover enough to bear it.

      And, I’m sorry to hear about your garden. These persistent chemicals are terrible, and very hard to trace back/prove that damage came from them, even if it seems obvious.

  3. Thanks for your prompt reply. I will remove all of the manure. I just
    noticed that the bean plants look okay. Apparently, beans are affected as well.
    Could this mean that it’s not the manure or am I trying to be optimistic?
    Also, I read that a lot of nitrogen can make them curl. I put a lot of
    chicken manure on–usually an infusion I make with the manure sitting in
    water in the heat for a few days. I have 28 chickens so I use a lot of it.

  4. Thank you for your prompt response.
    Now that I’ve looked at them again, I’m wondering if it could be too
    much nitrogen. The reason is that the beans look okay, and I read
    they are the ones that can also be affected. I have 28 chickens, and I
    make an infusion with the manure and water and let it get warm for
    a few days. Then I water the plants with it. Could that make the leaves
    curl–too much nitrogen? Also, the pepper plants are curling a little.

    • Hmm–maybe. Or maybe too much water. Don’t give your pepper plants too much nitrogen, though. You’ll end up with big, beautiful plants with no fruit!

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