It Happened to Us!
I say it often; it’s alright to make mistakes as long as you learn from them—especially in the garden. Well, I made a doozy recently and have I ever learned from it.
If you watched our Episode 406 on building out our GGWTV Vegetable Garden, you know how hard we’ve been working. I was especially proud when the time finally came to fill my beds with carefully selected, rich topsoil, organic compost and manure. And I was feeling particularly resourceful about utilizing the manure from right here on our farm. With horses, goats and chickens, we had a generous inventory that was well rotted and ready for the garden.
As a full time gardening communicator who prides himself at being in the know, I am also aware of the potential current hazards of using manure to amend garden soil. In recent years, it has become very apparent that some herbicides used to control weeds in farm fields persist for a very, very long time. Even worse, they don’t readily break down, even as composted manure!
So if I knew better, why did I do it? Chalk it up to my haste to fill my new garden beds, combined with the very unscientific assumption that it couldn’t happen to me syndrome. My rational for proceeding prior to the proper testing was also flawed. Conscience of the potential risk, I had been observing various weeds and plants springing to life from this massive, aged manure pile for weeks while failing to consider that not all plants are impacted by these herbicides in the same way.
Giving myself the green light to proceed with amending my soil with this free and abundant manure, I blended about 20% total volume to each bed in my garden. Then I planted every bed, including 20 varieties of tomatoes. And then I waited—and waited.
Something wasn’t right. As my new plants finally started to grow, their leaves were so twisted and distorted, while other plants were severely stunted. I knew what happened—I just refused to believe it was true, and that it happened to me! To add insult to injury, even the hay I used as mulch contained the bad stuff because it came from the same source.
About a month later I finally confirmed my suspicion. The farmer that grows the hay that we buy for our horses made his periodic delivery. I didn’t waste a moment; “What type of herbicides to you put on your fields?” I asked. “Grazon” he replied—not the answer I wanted to hear. It’s all I needed to know. The trade names for the products you want to avoid are many. But the active ingredients of greatest concern are picloram, clopyralid, and aminopyralid because they can remain active in hay, grass clippings, piles of manure, and compost for an unusually long time. These herbicides eventually break down through exposure to sunlight, soil microbes, heat, and moisture. Depending on the situation, the herbicides can be deactivated in as little as a few months yet complete deactivation and breakdown can take several years!
So what will I do now? Many people I’ve consulted with didn’t hesitate to suggest I remove the soil from every bed and start fresh. I agree, it’s the best way to tackle the problem head on. Yet, considering the time, energy and expense of filling each of the 16 beds the first time, I can’t stomach the thought of removal and starting over.
The other option, and the one I’m taking, is to leave the soil in place, hoping through bioremediation, I can heal the existing beds. I’ve grown out the plants that are already there to see how they ultimately respond. After that, I’ll turn the beds to expose the soil to more to sunlight and air, and promote the soil microbe activity in each bed and hopefully deactivate the herbicides more quickly. Then I plant cover crops in all the beds to keep the biological systems running above and below ground.
Thankfully, not all my plants were affected, yet hardest hit were the tomatoes, eggplant, peppers and beans. Remarkably, the cucumbers, okra, herbs, chard, beets, sweet potatoes and watermelon did fine, as did my ornamental annuals scattered throughout.
What should you do? Never use manure or even hay as mulch in your garden beds when you are unsure of the chemicals used in the field. It’s unfortunate but for now, it’s the only way you can be sure you are not transferring harmful, active herbicides to your garden. And lastly, farmers have a big responsibility in this as well. Please inform your customers if you are using herbicides that can be potentially devastating to home gardeners. My hope is that by next year, my soil will be restored and this is one mistake I know I’ll never make again.
If you want to see the segment we did on this for the television show, where Joe shows the actual damage and shows you how to test your manure before you put it in your garden, be sure to watch it here, in episode 410.