When compost turns toxic: beautiful garden or gnarly plants?
Hi Gardening and Wellness Friends 👋🏼
See how the leaves are curling over on itself-📷Mario Villarino
I’m so grateful for the gardeners who invest in their gardens by participating in the 2025 Fall Gardening Cohort. So many great questions arise. One question I’ve not yet touched upon on my socials or through my blog concerns compost. I was asked if black cow compost is okay to use. I don’t recommend black cow. Here’s why, an alternative, and a solution if you do have to use it.
Comparison of what a plant should look like and what a plant in soil contaminated by aminopyralid looks like-📷chatgpt
Six years ago, I was creating a new garden to expand my existing. I was a couple years into consistently replicating successful gardens. I designed, had help moving compost, created, and then I planted this large 38-foot by 22-foot garden. The plants were growing. A few weeks in I noticed my beans and tomatoes were looking gnarly. The leaves were shriveled up and curling over on themselves. I thought, maybe they were dehydrated, but after watering consistently for several days they didn’t improve. I noticed the plants seemed short and stunted. My corn was unaffected. My okra and squash looked close to normal. There was the slightest curling on the edge of the leaves, but the growth wasn’t stunted. My zinnias were unaffected. I had never experienced anything like this in any of my previous nine years of gardening. I was baffled.
I used the whole garden for flowers. This angle doesn’t do it justice, but it called in so many pollinators and I created many bouquets from that garden
I took to the interwebs, and Wow! What a whole new facet around gardening I discovered. It took me a while to narrow down my search and find this was an emerging challenge many gardeners were facing. Can you guess what was different about this garden compared to my others?
If you guessed the compost, you’re right. This compost I was using was manure based. It was a finished compost, meaning it completely composted normally. It didn’t burn my plants, but my beans and tomatoes weren’t thriving. What I found in my web search is that manure-based compost has one of several chemicals that are used to spray hay fields to kill weeds. The cattle or horses eat the hay, and the chemicals travel through the digestive tract into the manure. The manure is composted, but the chemical persists. The half-life of aminopyralid is 533 days depending on conditions, according to EPA.GOV. This means the chemical persists in the compost or soil potentially for years depending on the conditions, all the while wreaking havoc on the garden.
Some of the many bouquets the flower garden produced
This new garden was unusable for my organic practices, so I turned it into a garden for flowers. I grew only flowers in that garden for years. I turned that experience of ruining an entire vegetable garden into a blessing and created beauty. So many bouquets of flowers grew from that garden.
That experience caused me to think about my composting needs, where to source and how to produce. From that season on, I chose to source compost from a company that is certified OMRI listed. What I’ve found is sourcing from companies that compost tree matter, yields a product that is less likely to come in contact with these persistent herbicide chemicals. That was also the event that encouraged me to build a larger composting bin so I could produce more of my own compost.
How aminopyralids get into the garden and how to remedy
In the event there are few options available and black cow is one of those few options, then I recommend purchasing a bag, fill a cup with the compost. Add a couple of green bean seeds and observe them grow for 2 to 3 weeks. If the leaves grow normally, then use the compost in your bed, but at the first sign of deformation, curling or twisting then use the bag of compost to grow something you will not be consuming.
So when asked if black cow is good to use in the garden bed, I don’t recommend it. There are other sources that will keep our gardens more in line with organic gardening. I hope this gives you direction on what to use when filling your garden beds. If you need help finding a source near you, reach out to me and we can research together.
Until next time…..
🌿To our health and the health of our gardens🌿
Tina