Don’t be snookered

Just a short (but irritated) note about the latest fawning over compost tea. Please, people, as Jeff pointed out nearly two years ago on this blog, just because Harvard (and now Berkeley) buy snake oil it’s not transmogrified into science. Middle America would be better served by using compost as a mulch and letting nature make the tea.

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Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - "The Garden Professors" Facebook group - Books:

11 thoughts on “Don’t be snookered”

  1. During the school year, I have so little time for my garden that any shortcuts are welcome. Why on earth would I add more steps?

    One place I can see it being possibly worthwhile, though, is in fertilizing container plants. Right now, I’m experimenting with coffee grounds and cold coffee, though. When I bow down to the inevitable and start the fires again, I will also try an ash soup. We’ll see how it works out, but I don’t like buying fertilizer if I already have everything I need.

  2. Sarah, I sure don’t object to people using compost leachate as a weak fertilizer. It’s free and easy. Aerated compost tea made with all the “required” ingredients is complicated, expensive, energy-wasteful, and without scientific merit.

  3. compost tea is a great fertilizer, especially in situations where you do not want a high nitrogen liquid fertilizer. I do have a problem with your blog being very climate specific. some of the claims that you make are great for washington, but they are not universal. soils, climates and horticulture are very different in different areas of the world. I find compost tea use full as a low nitrogen fertilizer for growing native plants in containers until they are up to size. other liquid fertilizers like miracle grow, fish emulsion etc would not be appropriate.
    things that you reject like sheet mulching are vital in areas of the world where winter is not cold enough to kill weeds and weed seeds. I do not advocate specific products or snake oil, but I hate the idea that everyone assumes what works in one ecosystem suits all the others. As a ho
    rticulturist I spend most of my time correcting the illusion that people can plant and grow the same species from new england to new mexico. Please consider this when making large scale statements.

  4. Rachel, compost tea is not a “great fertilizer.” There’s no scientific evidence to support this. Likewise, your assertions that sheet mulches are “vital” flies in the face of the research which shows pretty conclusively that sheet mulches have negative effects on soil health when compared to other types of mulch. If you are a horticulturist, then I assume you use science to guide your practices and recommendations. If this is true, then please provide the science used to support your comments here.

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