Back in 2007, GardenRant hosted a Compost Tea Debate between the two knowledgeable Jeffs:
- Jeff Gillman’s Possible Benefits and Likely Problems with Compost Tea
- Jeff Lowenfels’ On Compost Tea: AACA (and Only AACA) Is the Real Deal
- Jeff Gilman’s Brief Rebuttal (all comments here)
I recently asked both Jeffs if they had an update for us, and Jeff Gillman sent me this response. Susan
Fifteen years of GardenRant, and 14 years since the Great Compost Tea debate. I wonder how many of you who are currently reading this article read that debate when it first came out. I remember it fondly. I have always enjoyed discussing science and at that time in my life I felt very passionately about delivering whatever science-based knowledge I had to whomever I could as forcefully as possible.
Life has changed a lot since then. I like to think that I’m no longer the 30-something tenured professor and self-righteous jerk that I once was. Not that bits of him don’t remain, but, to borrow a phrase from a Bob Dylan song (My Back Pages): “I was so much older then, I’m younger than that now.”
These days I run a botanical garden at the University of North Carolina in Charlotte and I’m concerned about much different things. Getting people to appreciate the science behind compost tea, gypsum, or complete fertilizers is the least of my worries. I share the world of plants with people who have barely been introduced to it. Thank goodness I work in an amazing garden full of magical greenery like Venus flytraps (a North Carolina native!), cacao, tea, yaupon and sweet birch to help get them engaged.
The State of Science-Based Gardening Info
To me, the debate about compost tea was actually about something greater than compost tea itself. It was about the appropriate use of science to support a garden practice. Science didn’t support the use of compost tea and it bothered me to my soul that anyone could recommend it without clear and published data to support its use. The only difference between then and now is that now I really don’t care if someone wants to try this odd and still unproven concoction (as long as they’re careful, because it is clear that compost tea could be dangerous under the wrong conditions).
I’ve come to the realization that people do things for many reasons besides science. I am still a scientist and it is still my responsibility to relay the relevant science about compost tea or any other issue when asked, but unless there’s a safety issue, I’m not going to engage in a long, protracted, idealistic battle. I can provide data, but ultimately the choice isn’t mine to make and I’m not going to take it personally if someone decides to ignore the science, which isn’t to say that I won’t feel some frustration.
Credit: West Virginia Extension Service
Yes, I would like science to have a more prominent place in the home garden, but as far as I can tell, that isn’t the way things are going. There was a time when the Extension Service, an organization that I was proud to represent, was the place to go for information, but how would a gardener who is just starting out even find the Extension Service today? How would they get beyond the commercial companies and the well-meaning, but marginally qualified “experts” that are at the top of the charts in most Google searches or omnipresent in most Facebook or Reddit gardening groups? Social media is entertaining, easy to access, and people with few real credentials can easily create a veneer of expertise and quality.
At this point university-based information is barely competing for the attention of the modern gardener. You can tell me about one or another wonderful and active Master Gardener program, but I’m going to remain unmoved. Relative to the total number of gardeners out there, Master Gardener programs are small and reach few people. To me, it looks like the universities have given up. Facebook wins!
I do have hope, though. There are groups, like The Garden Professors, that deliver science-based information. Right now they’re being out-competed, but with some support (and if they were just a touch less judgmental when delivering information), they could reach more people.
What would be really inspiring is to see stores like Lowes and Home Depot working with universities to provide science-based information to their customers.
Or maybe something crazy will happen like social media platforms starting to actually label information that comes from experts as….well….information that comes from experts. To have any meaningful effect, the platforms would need to go to the trouble of confirming that these self-described experts are actually and demonstrably experts, of course. I know it’s too much to ask, but wouldn’t it be amazing?
Thanks to Susan for inviting me back onto GardenRant. It has been a long time since I wrote a blog post and writing this has brought back some wonderful memories. If any of you are interested in the work that I do now, please check out the UNC Charlotte Botanical Gardens on its website, on Facebook, or our podcast The Plants We Eat, which is available wherever you get your podcasts. Happy Gardening!
I must endeavour to join you in the not minding much corner.
And you are so right about the Garden Professors: too many people have been alienated. I feel a rant coming on!
I used to think I’d like to be a garden coach when I retired from the corporate world but with so much free “advice” on social media, I ultimately decided I would not be able to compete. Instead I became a Master Gardener and fortunately that still holds some weight around here.
However, I now think that if people are not going to consider science-based principles and credentialed experts when it comes to their own health, then why would we think it would ever occur to them to apply those concepts to their landscapes.
Dr. Gillman. Thank you for bringing this to people’s attention. Science really should supersede commercial gains.
Have you studying the work of Dr. Elaine Ingham with the Soil Food Web? She is the only scientist I know of that is actively educating consultants on the proper use of teas/extracts made from aerobic/thermal compost – tested using microscopy to assess the true biological composition. That is the only safe way to develop compost and liquids that are effective.
Hi George,
With all due respect to Dr. Ingham, her techniques are not well accepted by the scientific community and so I categorize them as faith-based. This could change in the future, but right now I do not consider the practices that she recommends to be well supported by science. With that said she has quite a following and I don’t know of any injuries that have come from her recommended concoctions.
Yes, science-based gardening information is harder than ever for the public to discern from hocus pocus. The responsibility for this problem rests not in the Master Gardener programs or the universities, but with the state funding of the universities that support the county extension agents. Salaries have been slashed and excellent extension programs have been dismantled, not because they were ineffective, but because bureaucratic bean counters and legislators only care about protecting the “rainy day” funds. The extension agents and MGs are fighting the good fight and they deserve our support. If you have a Master Gardener program in your area, I encourage you to send them a donation toward the projects they support.
I’m with you all the way!
Science based. Trees talk to each other, and other plants. Life saving, life thriving information.
https://www.brainpickings.org/2019/07/10/trees-ted-ed/ , Ted Talk video more than worth your time.
https://www.brainpickings.org/2016/09/26/the-hidden-life-of-trees-peter-wohlleben/ , more science about how trees communicate.
Adore how WE are the slow pokes to horticultural science. Truly, life science.
Age 60, began professional gardening, with horticulture degree, age 25. Lots of new science across those decades in the industry. Yay. Yet, totally unexpected.
People, lifestyles, changed too. Distractions. Technology, media, entertainment, social media, politics, expectations, AI, sustainable vs regenerative, agrarian vs. HOA’s, etc….
Sweet revisitation today. Thanks !!
And, appreciate info in comments section.
Garden & Be Well, Tara
Alas, I agree with you on too many points. I trialed various such foliar amendments, but failed to see any marked differences among control plants and treated ones, and abandoned the effort as unnecessary. Other experiments varied from disappointing (e.g., the year of heavily mulching with coffee grounds was an interesting lesson in creating a hydrophobic soil crust with a side dish of minor allelopathy) or very successful. The latter involved various forms of sheet mulching one to two decades ago to kill turf and set the stage for ornamental beds. A lack of access to wood chips prevented me from adopting the approved mulching method forcefully and repeatedly advocated on the GP website, but my efforts were rewarded nonetheless, which undermined the credibility of at least some GP writers in my mind. That said, I also began adopting their counsel on root pruning & soil removal from nursery-grown woody plants, and can only say that I wish I had started doing that sooner and saved a couple thousand dollars worth of specimens. In the end, there is no substitute for curiosity, coupled with critical thinking, observation, and a willingness to abandon a beloved hypothesis. Many thanks for writing this post, and good luck in your new position.
Dr. Gilman, I have read all of your books. I am a functioning scientist at a retail store. I am the Horticulture Information Specialist. The thing that saves me is my dissecting microscope. I use it to diagnose samples that customers bring in to determine what is wrong with their plants, lawns, vegetables, etc. No one can argu with a microscope! The thing that frustrates me is the internet. Your Garden Rant article hit so many “targets”. Thank you, thank you, thank you! Science will always rule in my world, and I will always base what information that I share on the amount of documented sciene that proves it. (I read the original debate about compost tea and used your viewpoint to convince the management at the time to not carry it.)
Thank you! Smart and thought-provoking series. The rational scientific method needs to be embraced more often in American society.