The Microbial Underground
I recently read The Hidden Half of Nature, and was captivated by the first third of the book, where the authors talked about soil and harvesting a healthy microbial ecosystem. Starting with a “dead” dirt backyard in Seattle, the couple slowly transforms it into a vibrant ecosystem where their outdoor plants soon thrived after their soil experiments. They harvested soil, which was crawling bugs and other critters, and purportedly, a rich host of microbes.
The rhizosphere— where the plant roots interact with the microbes —was the site for transformation. Microbes are key here, extracting nitrogen, phosphorus and potassium (NPK) into usable forms for plants.
Plants symbiotically provide sugars, amino acids and other nutrients for these microbes to thrive. It’s one basic element of plant science, but we often forget this with large-scale farming, relying on pesticides and other growth agents.
For home use, I became entranced with making soil bins — what would appear here, in a soil system? Would I get the bugs they described.
A few weeks ago, I deployed three of these in a spot in Nevada City, where the soil is subject to intense heat. I’m not even sure how healthy the soil is, but it doesn’t look great
Aided by ChatGPT, along with my own research, I came up with three soil bins. Each one had about 4”-5” of healthy native soil — the existing bins had been maintained at some point, but had fallen into disrepair.
Bin #1: Moist Decomposer Habitat
Target insects: Earthworms, roly-polys, millipedes, springtails
Watering: High (6–10 GPH)
Cover: Open or lightly shaded, with a bark slab/log to retain moisture
Top Layers:
~1.5″ composted leaf litter (aged, moist)
~0.5″ rotting wood chunks (shredded or in small pieces)
Fine bark, wet leaves, and wet wood chunks mixed on the surface
Bin #2: Surface Predator Habitat
Target insects: Spiders, ground beetles, hunting crickets
Watering: Low (1–2 GPH)
Cover: Open
Top Layers:
~2″ coarse bark mulch
Flat rocks scattered on top to create temperature variation and shaded hiding spots
Bin #3: Fungal & Organic Matter Habitat (Biochar Bin)
Target insects: Springtails, compost beetles, mycophagous beetles
Watering: Moderate (3–4 GPH)
Cover: Open, with a few bark shards for shaded fungal refuges
Top Layers:
~1″ humus or well-aged compost
~1″ straw mulch or leaf mold
1 quart activated biochar, spread evenly across the top layers
Two freshly cut wood pieces placed to encourage fungal colonization
I’ll be observing these over the next few months, checking moisture levels with my sensors, looking for bugs and seeing if fungal life grows there. What’s the goal? Who knows exactly, but curiosity is driving my inquiry.