(VIDEO) How to Fix Damaged Garden Soil
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While our garden looks lush now, a year ago there was almost nothing growing in these very same beds. We believe the reason was accidental herbicide contamination from compost and mulch. Sadly we are hearing this is a growing problem for gardeners all over the world. If you are dealing with a damaged garden, it can be confusing and very discouraging.
But not all hope is lost!
Today we are going to share our story of how we healed a poisoned garden. We are going to cover what we did wrong, how we figured it out, the steps we took to remediate the problem, as well as provide suggestions on how you can avoid ever having to go through this yourself.
Going from Cancer to Country Living and Our first Homestead Garden
After nearly 2 decades of urban homesteading in rental units, we finally made our country living dream come true after Kevin was diagnosed with autoimmune illnesses and I survived breast cancer. We bought our property (less than 2 acres) in 2018 and while it had a house and a shed, it had no other infrastructure. Due to complications with my health issues, we were not able to put in a large garden until two years later. In 2020 we raced to get things set-up for a fall and winter garden, knowing that come next spring, we could really dig in. We made our own soil mix relying heavily on bagged compost from steer, chickens, and mushroom-growing operations.
Our first “off season” season garden did pretty well. The greens thrived but the root veggies were a little small. After gardening for nearly two decades year-round in the neighboring zub-zone, I knew that even more abundance was possible. I had also learned that the secret to an abundant garden is healthy soil ecology. So in March of 2021 I did a soil test. I sent my soil samples to a lab and had them professionally analyzed. I got the feedback that things looked alright. Since I got the green thumbs up, I decided to only mix more compost into the soil and mulch the beds
How did we contaminate our garden?
After thoroughly researching compost producers in my area, I chose a local supplier that uses a lot of horse manure. I had learned that the microorganisms in composted horse manure are very good for the soil. I was also excited to finally be able to use straw mulch. This is the first place we have lived where we can easily purchase and store straw bales. I ordered a delivery of locally-grown straw from a feed store.
At the same time we were boosting our beds, we were also starting baby vegetable plants indoors. We opted to use the same mix from our garden for seed-starting.
Little did we know that the very things we were trying so hard to do right, were the very things that made everything go so wrong in our garden.
How did we know we contaminated our soil?
Looking back, the signs were there from the start. Plants will tell you when something is wrong, if you are paying attention. The seeds we started indoors and outside were stunted. Even transplants we purchased would start to grow and then just stop or become strangely deformed.
At first this was deeply distressing. After years of planning, working, and nearly dying, we finally had our dream garden. Yet nothing would thrive. I have to admit that I had a few dark moments of scrolling through instagram and seeing gorgeous gardens while mine was withering.
But by this point I had been gardening long enough to know that nobody is born with a green thumb. We can all learn to grow a garden, and I’d had plenty of success. Something was wrong and it wasn’t me. So We set out to solve the mystery.
How did we figure out our garden soil was contaminated?
Kevin and I are scientists. So once the initial frustration passed, we got curious. We began to ask ourselves, what would cause these garden issues? There are many, many factors that can cause gardens to fail.So we started with a process of elimination.
Was it seeds? Nope. I learned that lesson early in my gardening adventures. Now we only buy from reputable seed companies.
Was it weak transplants? Nope. We grow our own or buy from trustworthy gardeners. We also made sure to harden off all of our plants so they were adapted to the weather.
Was it temperature or watering? Maybe. While we’d had unusually high temperatures and let the outdoor garden dry out a bit, this seems unlikely as the indoor starts were very well controlled and still showing issues.
Was it our soil? This one seemed like the biggest mystery. In the spring we did complete soil testing and analyzing. This revealed that our pH was slightly off, but nothing dramatic. Yet recently we had added more compost and mulch.
That’s when we went into research mode. We did deep dives for answers, reading research papers and toxicology reports as well as learning from other gardeners who had run into issues. Along the way we learned about herbicide damage to home gardens from compost and mulch. In particular, Charles Dowding has discussed at length the issues with horse manure and Jill Winger has documented deformed tomato plants that looked similar to ours.
In our research we found that a relatively new family of herbicides has become widely used since about 2005. These herbicides are geared at eliminating broadleaf plants (weeds) in hay and straw, allowing the farmers to get a higher price for their crops. They are touted as “low toxicity” meaning that they don’t appear to persist in the bodies of fish, birds, and mammals.
In our research we found reports indicating that these herbicides DO persist in the environment for months or years, even after being digested by animals. It’s called herbicide carryover. And because these poisons can last in soil for so long, it can be nearly impossible to trace the original source. The problem for home gardeners like us is that vegetable crops are sensitive to these herbicides. If plants like peas or tomatoes come into contact with the residual pesticides in compost or mulch, they can be permanently damaged.
When we began to suspect that herbicide poisoning might be the cause of our garden issues, we wanted to find conclusive evidence. We searched for a lab that would test our soil for trace amounts of herbicides. Unfortunately we were not able to find a laboratory that would test our relatively small home garden soil for residual herbicide contamination.
So we decided to try to do some testing of our own. We performed a bioassay test. We used the process outlined by Corteva Agriscience, which is a part of the DowDuPont chemical company. In this test we used garden pea seeds in a variety of soils, including mixtures from the garden areas we were beginning to suspect were contaminated. While we noticed some issues, there was nothing absolutely conclusive from our bioassay test.
How did we fixed our contaminated garden soil?
While it was disappointing we could not find solid solid proof of exactly what went wrong in our garden, the evidence pointed to accidental herbicide poisoning. So we decided to treat our garden as if it was contaminated. Over the course of seven months (September through March) we took steps to address our damaged soil. Here is exactly how we remediated our soil:
Removed all the straw mulch. We spread this on our forest trail as we don’t want plants to grow there.
Removed 50% of the raised bed garden soil. We couldn’t afford to replace it all, which would have been preferable.
Replaced the removed soil with high-heat compost. In our area, Cedar Grove compost ensures their products have been treated with high-heat to break down toxic chemicals.
Added worm castings. We harvested castings from our own worm bin, but these can also be purchased. They are a gentle fertilizer that rich in microbes, helping fight soil-borne diseases.
Added mycorrhizal fungi. We purchased a granular product made by Plant Success Organics. They help enhance and diversify the microbiome of the soil to help establish beneficial micro organisms in the soil.
Added activated charcoal. We used Andersons BioChar DG Organic Soil Amendment. We soaked it in a bucket of water for nearly a week. This carbon-rich product helps improve soil structure and fertility.
Added liquid algae. We used a liquid product called Regenisys from Corona Enterprises. We added it to the bucket of water with the activated charcoal. This product was proven effective on herbicide damaged soil at high school in Montana.
Changed mulches. We are now using plant debris from our own land, cardboard, coconut coir, and hemp chaff pet bedding instead of straw. While there are strengths and weaknesses to each of these, none of them are known to be sources of herbicides.
How can you avoid accidentally damaging your garden soil with herbicides?
Avoid compost that could contain straw or hay. This includes bagged steer, chicken, and mushroom compost commonly found at local stores. Each of these products has hay or straw inputs at some point in their supply chain.
Source high-heat compost products. Large-scale municipal facilities can regulate their temperatures to break down toxins.
Build your own worm bin. Vermicompost can be made in even small spaces and contains many beneficial organisms. Check out our video about setting up a worm bin system.
Avoid straw and hay as mulch. It is very hard to trace the source of hay or straw in order to find out if herbicides have been used on it. So we recommend avoiding it all together.
Use certified organic products whenever possible. While it’s not always easy to find or afford the organic versions of garden amendments, it is far less likely they will contain poisons.
Continue improving your soil microbiome. Just like our own wellness, health is not a “one and done” thing. Continuing to monitor your soil and plants, while adding amendments as needed, is an ongoing process.
As grateful as we are to be alive and well enough to have a garden, this issue scares me. Kevin and I both have serious health issues related to our immune systems and no expert has been able to explain exactly why. We worry that there are still poisons lingering in our garden that could be detrimental to our long-term health.
We put a lot of time, effort, and money into starting this garden right and still ended up with a devastating problem. It has highlighted for us that no matter how self-sufficient and sustainable we try to be, there are still these big industrial systems that can affect us.
But all hope is not lost. When we look around this garden today, we see how far we have come in the last year. That has been thanks to the many hearts and hands around the world who have helped us with their knowledge, products, and with the courage to share their stories. And most of all, our spirits are lifted by the tremendous resiliency of nature to heal itself.
We are grateful for each leaf and fruit that we are enjoying now. We hope that while you never have to face this situation, our experience will help you heal your own garden if you do face this situation.
Welcome to Wild Notes. In this series take a walk on the wild side with Kevin to see the natural world from the perspective of a seasoned naturalist. In this first article meet a pair of hunting American Kestrels.