Getting your soil test results back feels exciting. You hold numbers that reveal what is happening beneath your feet. But staring at those numbers can feel confusing if you do not know what they mean or how to use them.
DIY soil testing has made understanding soil health accessible to everyone. Instead of sending samples to distant laboratories and waiting weeks, people can now test their soil on-site and get immediate answers. This guide will help you understand those results and use them to improve your land.
Importance of Testing for Microbial Biomass
Many people make changes to their soil based on guesswork. They add fertilizers, compost, or other amendments, hoping for improvement. Traditional soil tests measure chemical properties like nitrogen, phosphorus, and pH levels through various methods. These numbers provide useful information but miss the biological side of soil health. Living organisms in the soil drive nutrient cycling, water retention, and plant health.
Microbial biomass encompasses all the living organisms in your soil sample. This includes bacteria, fungi, and other microscopic creatures. Think of it as counting the population in an underground city.
Higher microbial biomass numbers usually indicate more biological activity, which can translate to better plant growth, reduced need for fertilizers, and improved resistance to drought. Lower numbers suggest the soil needs help building its living community.
Understanding the Fungal to Bacterial Ratio
The second key measurement is the fungal to bacterial ratio. Soil contains both types of organisms, but different plants prefer different balances. This ratio helps determine what type of ecosystem exists underground.
Bacteria thrive in disturbed soil and support annual plants like vegetables, grains, and grasses. These organisms multiply quickly and break down fresh organic matter rapidly. Gardens and agricultural fields typically show higher bacterial populations.
Fungi prefer undisturbed environments and support perennial plants like trees, shrubs, and native grasses. Fungal networks extend through soil, connecting plants and moving nutrients over long distances. Forest soils naturally contain more fungi than bacteria.
How to Read Your Numbers In Soil Testing?
Real-time soil testing provides immediate data, but understanding context makes those numbers meaningful. The same soil can show different results depending on season, moisture, and recent weather conditions.
Spring and fall typically show higher microbial activity than summer or winter. Warm, moist conditions help microorganisms thrive. Extreme heat or cold slows their activity. Compare results from the same season to track true changes.
What Good Results Look Like In Soil Testing
Healthy agricultural soil typically shows microbial biomass levels above 600 micrograms per gram. Garden soil often shows even higher numbers because gardeners regularly add compost and organic matter and gardens can be managed more frequently due to their size. Really excellent soil can reach 1000 or higher. These numbers indicate strong biological activity supporting plant growth. However, this is largely dependent several factors including your climate, region, soil type and texture.
Conclusion
Soil microbial biomass testing provides powerful insights when interpreted correctly. These numbers reveal the health of the underground ecosystem supporting all plant growth. Understanding and acting on this information creates healthier, more productive land that requires fewer external inputs while producing better results.
Most people never think about the dirt beneath their feet. They see it as something that makes their shoes messy or their hands dirty. But soil is actually alive with billions of tiny creatures that keep our entire planet running.
Soil health = planet health is not just a catchy phrase. It represents a real connection between what happens underground and the air we breathe, the food we eat, and the water we drink.
What Do Soil Microbes Actually Do?
These tiny organisms perform jobs that keep our planet functioning. Without them, life as we know it would stop. Soil microorganisms break down dead plants and animals. They turn this material into nutrients that new plants can use. This recycling process has continued for millions of years.
They also help plants grow stronger. Some microbes form partnerships with plant roots. They bring water and nutrients to the plant. In return, the plant gives them sugars. This teamwork benefits both sides.
The Carbon Connection
Climate change worries many people today. Soil microbes play a huge role in this challenge. They help store carbon underground instead of letting it float into the atmosphere as carbon dioxide. Soil biology acts like a carbon sponge. When microbes are healthy and numerous, they lock carbon into the soil. This process removes greenhouse gases from the air naturally.
Damaged soil with low microbial biomass and activity cannot store carbon effectively. The carbon escapes back into the air, exacerbating climate issues. Protecting soil life helps fight climate change.
Why Soil Health Matters for Food?
Farmers face increasing pressure to grow more food for our growing population, while facing the need to use fewer chemicals and resources to have more sustainable growing practices. Plants growing in soil rich with microbes need less fertilizer. The microbes provide nutrients naturally and help soil hold water better, reducing the need for irrigation.
Living soil creates stronger plants that resist pests and diseases. This means farmers can use fewer pesticides and the food can become healthier, while the environment stays cleaner.
Testing Makes the Difference
You cannot improve what you cannot measure. This applies to soil health, too. Farmers and gardeners need ways to check if their soil management practices actually work.
Testing methods, such as the microBIOMETER®, measure soil microbial biomass directly. These types of tests show how much life exists in the soil. The microBIOMETER® also estimates the balance between different types of microbes. The fungal-to-bacterial ratio tells us about soil conditions. Different plants and ecosystems prefer different ratios. Vegetables like more bacteria, while trees prefer more fungi. Understanding these preferences helps growers manage their land better.
The Bigger Picture
When we improve soil health in one place, the benefits spread. Healthy soil reduces erosion, stores carbon, and supports both aboveground and belowground biodiversity.
Soil health = planet health because everything connects. The microbes in your garden affect the air quality in your neighborhood.
Soil looks simple. But a small clump contains an entire world teeming with life. Understanding microbial life in soil changes how people think about growing plants.
Microbial biomass carbon varies around a median of 206 micrograms per gram of soil.
The Invisible Workers Underground
Soil microorganisms, including bacteria, fungi, and archaea, drive essential soil functions such as nutrient cycling, organic matter decomposition, and disease suppression.
Bacteria often represent the most numerous group. They break down dead plant material and transform nutrients into forms plants can use. Some bacteria fix nitrogen from the air, turning it into fertilizer that plants need for growth.
Fungi contribute heavily to soil structure and the break down organic matter, significantly contributing to the conversion of carbon to stable organic matter. This makes fungi extremely efficient at building long-term soil health.
How Do Bacteria Help Plants Grow?
Bacteria do several important jobs in soil. As they decompose organic matter like leaf litter or dead roots, nutrients locked inside dead material are released and become available for plants to use.
Nitrogen-fixing bacteria work with plants in special partnerships. Bacteria like Rhizobium form symbiotic relationships that fix nitrogen, converting atmospheric nitrogen gas into usable ammonia that plants absorb through their roots. This free fertilizer helps plants grow strong without chemical additions.
Some bacteria dissolve minerals in soil. Bacteria such as Micrococcus, Enterobacter, and Pseudomonas play crucial roles in phosphorus solubilization, making phosphorus available for plant uptake. Plants need phosphorus for root development.
Understanding Fungi’s Critical Role
Fungi look different from bacteria; not only are they larger, but they have slightly different pigments. Fungal biomass is necessary for healthy soil—their size and structure give them special abilities.
Fungi break down tough plant materials like wood and tree bark. They produce special enzymes that dissolve lignin, the substance that makes wood hard. This decomposition creates rich, dark soil called humus that holds moisture and nutrients.
How Farming Practices Affect Soil Microbes
Fungi and bacteria keep each other in check through symbiotic relationships. Different plants prefer different ratios of fungi to bacteria. Annual crops may prefer lower fungal-to-bacteria ratios, while perennials prefer higher ratios. Forests have the highest ratios because trees depend heavily on fungal networks for nutrients.
According to a study by Lori et. al. in 2017, organic farming systems show 32 to 84 percent greater microbial biomass compared to conventional systems. Adding compost, manure, and cover crops feeds soil microbes and helps grow their populations.
Chemical fertilizers and pesticides harm soil microbial communities. Fungicides kill both harmful and helpful fungi. Without beneficial fungi, plants struggle to access nutrients and water. This forces farmers to add more chemicals, creating a cycle that damages soil health.
Understanding Soil as a Living System
Soil microbial biomass represents the foundation of productive agriculture and healthy gardens. When people protect and feed these microscopic workers, they foster plant-soil interactions and receive a stronger and healthier soil community.
Learning about soil microbes transforms how people garden and farm. Every decision—from whether to till, what to plant, and how to fertilize—affects billions of organisms working underground. Making choices that support microbial communities creates healthier soil, stronger plants, and better harvests that last for generations. Use the microBIOMETER® soil test to estimate your soil microbial biomass and ensure you have the healthiest soil possible.
Fred Way has joined forces with APN – the Agroforestry Promotion Network which was founded by Roland Frutig and Lucky Mukasa. He also collaborates with soil stewards and farmers from Kenya, Malawi, Uganda, India and Switzerland.
The group travels throughout Africa to Uganda, Egypt, Nigeria, etc. They have educational centers in Malawi and Uganda. Here they host classes several times a year covering various soil practices to assist local growers by enhancing their farming techniques and improvimg forest function. By utilizing microBIOMETER® in these classes, they are able to highlight the importance of soil biology as well as demonstrate how changes in microbial biomass and fungal to bacterial ratio have positive effects on soil.
Whenever they can, they supply farmers with a microBIOMETER® test kit to allow them to easily test and track their soil’s health. While they are still in the beginning stages, their goal is to be able to provide local areas with kits since they are used to determine how native, natural forests function as well.
Fred performed microBIOMETER® testing in a logged forest that was a primary source for rubber in the late 1800’s until tthe early 1900’s. Currently, locals are removing all dead wood for fuel which is creating a loss of food at the trophic level. They use Indigenous microbial organisms (IMOs) in manure and urine (mostly from cows), molasses and other regenerative practices to stimulate the soil. They have discovered that by using these materials, they are able to kickstart the regenerative system. microBIOMETER® has demonstrated that these somewhat unconventional materials are increasing fungal levels over time while bare soil that previously wasn’t producing is now showing signs of life. Their goal is to emulate what’s happening in the forest for their agriculture food production system.
“The affordability and compatibility of microBIOMETER® as well as the real-time results make it easy to understand and track results over time and see improvements quickly. The addition of microBIOMETER® PRO’s advanced calculations and moisture adjustments are a good addition to the test,” – Fred Way
Remember when you needed expensive equipment just to know what’s happening in your soil? Well now that same device you use to scroll social media and read the news can analyze soil health with lab-quality precision.
The Science Behind Your Pocket Soil Lab
Your smartphone possesses something laboratories have relied on for decades: sophisticated optical sensors and powerful processing capabilities. Modern smartphones can detect color variations, light intensity, and chemical reactions through their cameras and built-in sensors. When paired with the right testing reagents and apps, these everyday devices transform into legitimate soil analysis tools.
The principle is surprisingly straightforward. Soil samples react with specific chemical reagents, producing color changes that correspond to different nutrient levels, pH values, or biological activity. Your phone’s camera captures these color variations, while specialized algorithms interpret the data and provide instant results.
What Your Mobile Soil Lab Can Actually Measure
You might wonder what kind of soil data you can realistically expect from smartphone-based testing. The capabilities are more extensive than you’d think:
Real-Time Results That Actually Matter
The game-changer isn’t just the technology—it’s the speed. Traditional soil testing means collecting samples, shipping them to a lab, and waiting days or weeks for results. And by then, growing conditions and microbial communities may have changed completely. Smartphone-based soil lab technology delivers results in minutes, not days. This real-time capability transforms how you can manage your soil health. And the microBIOMETER® can help you do just that.
Notice your tomatoes looking yellow in mid-July? Test the soil immediately and adjust your fertilization strategy that same afternoon. Planning fall amendments for your lawn in Texas? Test multiple spots across your property in a single morning and create a targeted improvement plan.
Getting Started: Your First Mobile Soil Analysis
Setting up your smartphone as a soil lab is simpler than you might expect. The microBIOMETER® includes testing reagents, measuring tools, and a smartphone app that guide you through the entire process step by step. You’ll collect a representative soil sample, mix it with the provided reagents, and use your smartphone’s camera to capture the resulting color changes. The app then analyzes the images and provides detailed reports about your soil’s condition. The testing process is quick and you can see results in 20 minutes.
The Technology Revolution Happening Now
All-in-one smartphone-based devices are becoming preferable for agricultural soil analysis, enabling users to complete self-assessments about soil quality and receive performance reports with actionable insights.
The implications extend far beyond individual gardeners. Extension services at universities across the United States are incorporating smartphone soil testing into their educational programs. Community gardens in both rural and urban areas are using these tools to optimize their growing strategies and share soil health data among members.
Imagine this: The earthy scent of microbes breaking down leaves in the soil fills the air. Your harvest is complete, the season is winding down, and you’re likely looking forward to a well‑deserved break. But before you prepare for winter, seize the opportunity to assess the health of the microbes in your soil. It will pay off next spring! Testing microbial biomass carbon (MBC) and fungal-to-bacterial (F: B) ratios during autumn sets the stage for healthier, more resilient soils next spring. This proactive step is in your hands, and it’s a crucial one.
Here’s why autumn is the sweet spot for measuring soil biology:
1. Post-harvest tests show the real impact of your management
Sampling during autumn captures the “end-of-season report card” for your soil. It reflects how crops and cover crop management shaped microbial life through the growing season. Studies by Cornell University show post-harvest data shows differences between treatments, with diverse cover rotations supporting higher microbial activity compared to standard fallow fields. In other words, autumn tests provide a clear picture of how your decisions paid off biologically.
2. Results guide action plans for the winter
Nebraska Extension notes that low MBC signals low biological activity and carbon availability—exactly the type of challenge that can be addressed when you act ahead of spring. Autumn is your window to respond before soils go quiet in winter. If MBC trends low, you can jumpstart recovery with practices like:
3. Amendments need time to work
If you know your soil is acidic and requires lime, autumn or manure additions, autumn is the best time to make applications and alterations to the microbial ecosystem. Amending now gives the soil several quiet winter months to equilibrate, ensuring pH is in the right range for nutrient availability and microbial activity by the time you plant again.
4. Fall testing builds valuable trend data year over year
Soil health is about direction, not just snapshots. Measuring MBC and F: B ratios every autumn lets you to track whether regenerative practices are truly building biology year after year. That trendline is powerful for farmers, researchers, and anyone looking to prove results.
Final Takeaway: Think of fall microbial testing during autumn as giving your soil a health check before it goes to sleep. You’ll capture a clear understanding of how the season’s management impacts microbes and receive the insights you need to act. When spring rolls around, and microbial life ramps up, you’ll be ready with soils that are biologically prepared for partnering with plants in helping them grow.
Successful composting depends on understanding the microbial life within your compost pile. This is where soil testing kits become invaluable tools for gardeners and farmers alike. Modern testing technology allows you to analyze your compost’s biological activity with scientific precision, ensuring you create nutrient-rich amendments for your soil.
Understanding Compost Biology
The foundation of excellent compost lies in its microbial ecosystem. Billions of bacteria, fungi, and other microorganisms work together to break down organic matter into valuable nutrients. These microscopic workers determine whether your compost becomes a powerhouse of plant nutrition or simply decayed organic matter with limited benefits. Bacterial populations typically dominate the early stages of composting, breaking down simple compounds like sugars and proteins. As the process continues, fungal networks develop to tackle more complex materials such as cellulose and lignin. The balance between these microbial communities directly affects the quality and effectiveness of your finished compost.
The Science of Compost Testing
Traditional methods of evaluating compost quality relied heavily on visual inspection, smell tests, and temperature monitoring. While these indicators provide useful information, they cannot reveal the true biological potential of your compost. Modern soil testing kits offer scientific analysis that goes beyond surface observations. Microbial biomass testing measures the total amount of living microorganisms in your compost sample. This measurement indicates the biological activity level and helps predict how effectively the compost will benefit your soil. The fungal-to-bacterial ratio represents another critical measurement that influences how compost affects different types of plants. Vegetables and annual crops typically prefer bacterial-dominated compost, while trees, shrubs, and perennial plants benefit from fungal-dominated amendments. Understanding these ratios helps you tailor your compost for specific garden applications.
microBIOMETER® Technology Advantages
The microBIOMETER® advanced testing platform system brings quality analysis to home composters and small-scale farmers. These tools eliminate guesswork by providing quantitative data about microbial populations in compost samples. The testing process involves extracting microorganisms from compost samples and analyzing the color intensity of the solution using specialized reagents, measurement cards, and the microBIOMETER® app. Results appear within minutes, allowing you to make immediate adjustments to your composting process if needed. This standardized approach ensures reliable results that you can track over time to monitor improvements in your composting methods.
Conclusion
Regular testing throughout the composting process helps identify optimal harvest timing. Compost that appears finished may still contain high levels of bacterial activity, indicating continued decomposition. Investing in soil testing kits transforms composting from an art into a science-based practice. Understanding the microbial life in your compost empowers you to create consistently high-quality amendments that maximize plant health and soil fertility. Modern testing technology makes this level of analysis accessible to gardeners at every skill level, building confidence in composting success.
Prolific Earth Sciences is excited to announce the release of microBIOMETER® PRO. This extensive update has been three years in the making and features improved precision, increased consistency between phones, advanced nutrient metrics and sample geolocating. Please update your microBIOMETER® Reader app to 3.8.6 to access the PRO version.
What’s NEW!
• Test card. We redesigned the test card to reduce variance in results between phone models and better adjust for different lighting.
• Results. The results are now expressed as microbial biomass instead of microbial carbon.
• Moisture: We have changed the moisture assumption in our algorithm from 40% to 20% which is more in line with average soils. We also added a feature to allow users to adjust the moisture assumption to reflect soils with moisture contents closer to 10% or 30%. Moisture assumption for compost testing remains at 40%
• Geolocation: This new feature allows users to save the location where their sample was collected and perform the test at a later time while keeping the recorded sample location.
• Advanced Nutrient Metrics: As an understanding of how microbes contribute to nutrient availability increases, we have added calculated metrics to help users understand how their soil microbes are contributing to nitrogen and carbon stores in the soil. These are results extrapolated from microBIOMETER® results and the calculation and assumptions are detailed in the app informational pop-ups and our website FAQs.
• Soil and Compost: The PRO version will test both soil and compost, however, will no longer support direct testing of compost tea or extract.
With the exception of the test cards, all the supplies as well as the instructions will remain the same whether using the Classic or PRO version. The updated app will prompt you to choose a version so you can still use the classic test cards. We will also be selling Classic cards in refills for the foreseeable future. However, all new Starter Kit purchases will now be the PRO version only and contain the new test cards. For customers with ongoing trials, you may want to continue with the Classic test cards to track changes based on historical benchmarked tests.
In the updated app, we have made significant changes to units, underlying assumptions, and calculations. Therefore, we encourage users to continue with one version within a study or experiment since comparing the absolute values of the two is difficult. We have always encouraged using microBIOMETER® as a benchmark test and to focus on the changes over time. We will continue to supply the microBIOMETER® Classic test cards so that ongoing studies and trials can continue. However, we strongly recommend using the PRO version for all new testing and studies.
We would like to thank all of our customers that have given us feedback over the years. Your comments, both good and bad, have helped us improve the microBIOMETER®. Please keep sharing! And as always, we appreciate your continued support.
Bucknell University is a private liberal arts college in Lewisburg, Pennsylvania with excellent research facilities and innovative teaching. Students get the opportunity to work closely with professors in their chosen field.
Students in the Biology 203, Integrative Concepts in Biology, laboratory have a unit all about soil. The students visit the Bucknell Farm to learn about the properties of healthy soil. They then pick a location on campus to study. Students study the health of the soil in different conditions, such as soil with native flowers growing compared to soil under a tree. They measure microbial biomass, soil respiration rate, and various other soil properties to determine the overall health of the soil.
“The microBIOMETER® test allows students to quickly and easily measure microbial biomass and the relative amounts of bacteria and fungi in the soil. It is easy to use for non-experts with very quick results! We have measured huge differences in the microbial biomass at locations across Bucknell’s campus and have been surprised to have very high levels of biomass in the grassy areas, too!” – Rebekah Stevenson, Director of Core Course Laboratories – Biology Department
American BioChar Company is a Michigan-based company run by longtime green industry couple, Mark & Laurie Mann. For more than two decades, they have been researching and developing programs and products to improve soils, root conditions, and plant growth in urban, rural, and agricultural landscapes.
Over the last 3 years, they have conducted trials on blueberry farms in SW Michigan, using the microBIOMETER® and other soil-metric tests. The trials compared soils of blueberry bushes treated with their VITAL Blend soil amendment to those with untreated soil. Data was collected in the spring, summer and fall each year to demonstrate the natural ebb & flow of microbe communities in soils. Not only does the data show the steady increase of soil microbial biomass, but overall the trial sites have improved soil structure and more nutrient dense crops.
“The biggest impact we have in using the microBIOMETER® is demonstrating the successful transformation within the soil, following applications of our different biochar blended soil amendments. It provides confidence in our product and helps move the client conversation toward the biological benefits of our product. When a client is able to see and track the fungal to bacterial ratio for their soil overtime, it is very empowering.”
American BioChar is also undergoing several other trials throughout the mid-west with corn, cannabis, soybeans, and tree rhizospheres, using both their VITAL Blend and their new GRATEFUL Blend living soil. As both blends provide active and fixed carbon to soil, these trials were aimed to enhance and increase soil biology and restore nutrient density. Pre- and post- application photos can show how these products improved overall crop production.
Recently, Laurie Mann and microBIOMETER® president Laura Decker participated in Heart & Soil Magazine‘s Soil Summit discussing “How to Increase the Speed of Microbe Growth”. Click here to watch!
