View flipbook
Download current issue
Archives
Salk Institute Advice from plant biologist Lena Mueller, PhD
Advice from plant biologist Lena Mueller.
When gardeners ask me what soil or fertilizer is best, I often give a surprising answer: Choose whatever supports the healthiest soil microbiome in your local environment.
The soil microbiome is the diverse community of bacteria, fungi, and other microorganisms living underground. These microbes are essential for healthy plants, including garden vegetables and crops.
Every soil has its own resident microbiome, shaped by factors such as pH, nutrient composition, density, and the types of plants growing there. But human activities such as heavy fertilizer use, pesticides, tilling, monoculture planting, and erosion can disturb or damage these microbial communities.
So why do microbes matter so much?
One key group I study is arbuscular mycorrhizal fungi. These fungi form partnerships with plant roots, protecting them from pathogens and delivering nutrients such as phosphorus, nitrogen, zinc, and water. Their fungal networks also act as “highways” for other microbes and support soil carbon storage—fuel for the entire microbial ecosystem.
Healthy microbes build healthy soils and healthy plants.
LENA MUELLER, PHD
Other beneficial soil microbes can produce hormones that stimulate plant growth, improve nutrient uptake, and suppress harmful pathogens.
I encourage gardeners to help cultivate a healthy soil microbiome by:
- Adding organic matter such as compost or mulch
- Reducing chemical fertilizers and pesticides
- Limiting soil disturbance (try no-till gardening)
- Growing diverse plant species year-round
Microbial inoculants, such as arbuscular mycorrhizal fungi spores, are available commercially, though their effectiveness is still debated. They likely won’t do any harm, but may not always have an effect.
Ultimately, my advice is simple: Focus less on quick-fix fertilizers and more on nurturing the living ecosystem beneath your feet. Healthy microbes build healthy soils and healthy plants.