“Weeds Are Friends Not Problems — with Dr Mary Cole”
Why do weeds keep showing up — and what are they trying to tell you?
In this Farming Secrets webinar, world-renowned soil scientist Dr Mary Cole turns the usual weed conversation on its head. Instead of seeing weeds as the enemy, Mary explains why they may actually be useful messengers from your soil.
Watch the replay to discover what your weeds are revealing, why they appear, and how understanding them can help you make better decisions on your farm or garden.
Chapter Highlights:
Sustainable Agriculture and Soil Practices
Dr Mary Cole, known as the “soil whisperer,” explains how 230 years of European-style farming has damaged Australia’s fragile soils. She highlights the harm caused by tillage and ploughing, which destroy soil life, including vital mycorrhizal fungi. Her message is clear: open the soil without turning it over, protect ground cover, and preserve the living biology between drill lines.
Mycorrhizal Fungi and Soil Health
Dr Mary Cole explains that mycorrhizal fungi are essential to healthy soil, helping support soil structure, water movement, plant health, and biodiversity. Conventional ploughing destroys these fungal networks, along with organic matter and microbial life. She highlights that even a teaspoon of healthy soil can hold vast fungal and bacterial diversity, and that increasing soil organic matter can greatly improve water retention and farm resilience.
Sustainable Farming Practices
Why is conventional plowing destructive to soil health and agriculture? Dr Mary Cole highlights that it leads tothe use of toxic chemicals and contributes significantly to CO₂ emissions. She explains the benefits of no-till farming and pasture cropping methods, which maintain 100% soil cover and support mycorrhizal fungi, essential for nutrient access and plant health. Dr Cole emphasizes the importance of preserving these natural systems to ensure sustainable food production and leave a better legacy for future generations.
Regenerative Agriculture and Soil Health
Nature provides ample nitrogen through various biological processes including legumes, bacteria, and fungi, but synthetic fertilizers like urea damage these natural systems. Discover how farms transitioning to regenerative agriculture increased their nitrogen potential from less than 6 kilograms to over 350 kilograms through organic matter addition and maintaining 100% vegetation cover. Excess phosphorus and glyphosate damage plant health and microbiology, with Dr Cole sharing evidence of how compost tea effectively controls weeds like capeweed without chemicals, demonstrating the benefits of fungal-dominated soil systems.
Soil Health and Microbiology Research
Compost tea can shift soil biology, helping move the soil toward a healthier balance of fungi, protozoa, and other living organisms. This fits with the wider understanding that soil health depends on the soil’s ability to function as a living ecosystem that supports plants, animals, and people.
Farmers and growers are encouraged to look at weeds differently — not simply as enemies to kill, but as signs that the soil may be missing nutrients or biological balance. Managing weeds through improved soil health, plant diversity, and biological approaches aligns with research showing that fungi, bacteria, viruses, and beneficial endophytes can influence weed pressure and plant competition.
Regenerative Farming Methods Discussion
Dr Mary Cole explains her approach to regenerative farming, describing how farmers use methods like yeoman’s plowing and multi-species seeding with annuals and perennials to restore soil organic matter. She details the use of compost tea as a more effective alternative to direct compost application, particularly when working with large areas or during planting. When asked about thistles, Mary clarified that they are edible and not problematic, suggesting they should be cut off before they can photosynthesize to prevent them from establishing.
Up next: Informative Q & A
Participants asked questions about specific weed management, mineral testing, and implementing regenerative agriculture practices, with Dr. Cole providing specific advice on using rock dust, compost tea, and rotational grazing to build soil health. She recommends compost teas and multi-species planting to choke out weeds. Dr. Mary also addressed questions about identifying mineral deficiencies in plants, suggesting the use of Google Scholar and books like “When Weeds Talk” for research, using local rock dust rather than commercial trace elements for worm farms, The discussion concluded with Dr. Mary emphasizing the importance of soil health for plant and human health.
Dr Mary Cole’s key message is practical: build healthier soil through compost teas, rotational grazing, diverse crops, and strong plant vitality. Healthy soils support nutrient cycling, water retention, and more resilient farming systems.
Ready to build healthier soils and reduce your reliance on costly inputs?
Learn practical, proven ways to improve soil biology, grow stronger plants, and farm with more confidence.
Keen to know how to make compost tea the right way?
Discover Dr Elaine Ingham’s Complete Compost Tea Workshop and see how soil biology, compost, and compost tea can help you build healthier, more resilient soil.
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