Recently, the Soil Association team was at Woodoaks Farm in Hertfordshire, England collecting soil samples as part of the AI 4 Soil Health project (AI4SH). Madeleine Silberberg, Project Coordinator, coordinates 13 pilot sites across the continent in partnership with leading European institutions. These sites, covering 11 pedoclimatic regions, were selected based on distinctive soil qualities. The team are using advanced measurement techniques, generating new insights into the health of Europe’s soils, testing the assumptions in their models, and helping determine the best monitoring tools for the future.
Soil Association Farming Advisor, Karen Fisher, shares her experience using microBIOMETER® on this project.
“microBIOMETER® turned out to be a genuinely exciting addition to the toolkit. The first test took me a little while, carefully following the instructions step by step, but once I got into the rhythm the process was surprisingly straightforward. The longest part was waiting for the sample to develop but that slotted in nicely while we collected bulk density samples and soils for lab analysis.
I did have a small hiccup with scanning the first card, but I think my app might have been on the wrong mode, but after that everything worked perfectly. Each scan felt a bit like opening a present. I found myself looking forward to seeing what the next result would show.
It was fascinating to see the different patterns emerging across woodland, permanent grassland, conservation fields and compost. Some results weren’t quite what you might expect, for example, a woodland showing a lower fungal: bacterial ratio than a long-term grass field. It is a reminder that context matters: soil biology reflects both current conditions and land use history, and sometimes regeneration takes time.
These kinds of rapid, field-based tools do not replace lab analysis, but they bring soil life into focus in a way that is both practical and accessible. Over time, repeating these tests across seasons and management practices will help us build a richer picture of soil health and feed into the development of different indicators.”
Senior Farming Advisor Josiah Judson, “‘It was great to be out in the field making sure the tools we’re developing actually make sense on the ground and can support different users. It’s an ambitious goal to map these things across so many different landscapes, but the more data we can get, the better!”
Urban gardening isn’t just about growing tomatoes in a small closet. It’s about understanding the complexity of soil microbes in unconventional spaces and utilizing new methods that make city gardening not only possible, but also incredibly rewarding.
Plants with healthy microbial communities in their root zones tend to grow more vigorously and are better equipped to withstand stressors such as drought, pests, and diseases. In urban environments where plants face challenges like air pollution, heat islands, and limited space, this microbial support system becomes even more crucial.
Urban soil faces unique challenges that rural farmland doesn’t necessarily encounter on a daily basis. You’re dealing with:
Start with Quality Organic Matter
Your soil microbes are essentially composting machines, but they need fuel. Add compost, aged manure, or leaf mold regularly. These organic materials provide the carbon and nutrients that feed your microbial community. In cities like Portland and Seattle, many neighborhoods now offer community composting programs—take advantage of them!
Test and Track Your Progress
Understanding your soil’s microbial health doesn’t have to be guesswork. Modern soil testing technology allows you to monitor microbial biomass and the fungal-to-bacterial ratio right from your balcony or rooftop garden. This data helps you understand whether your soil management practices are actually working.
Minimize Chemical Disruption
Synthetic pesticides and fertilizers can disrupt your carefully cultivated microbial community. Instead, focus on building soil biology through organic amendments and natural pest management strategies. Beneficial soil microbes perform fundamental functions such as nutrient cycling, breaking down crop residues, and stimulating plant growth.
A recent study reported by the NIH reveals an intriguing connection between gardening and human health that goes beyond fresh vegetables and exercise. It found that frequent exposure to environmental microbiota, especially through skin to soil contact, diversifies commensal microbiota, enhances immune modulation, and ultimately lowers the risk of immune-mediated diseases.
As more Americans embrace urban gardening & soil health practices, we’re seeing innovations that make microbial monitoring and management more accessible than ever. Whether you’re growing herbs on a fire escape in Brooklyn or maintaining raised beds in a Phoenix community garden, understanding and nurturing your soil’s microbial community will help you grow healthier plants while potentially benefiting your own well-being.
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.
Can Grow Crop Solutions, a company focused on providing market-leading fluid solutions and service, has been incorporating microBIOMTER® into their business with positive results. Shawn Brenneman, Director of Commercial Growth & Strategy at Can Grow, shared a bit about their company and the testing they are performing.
Vibrant, diversified soil biology is essential in growing crops for maximum yield and quality, Can Grow works with farmers on getting the most out of their cropping systems. They do this through increasing nutrient use efficiency, reducing crop stress, and helping soil/biological systems function at higher levels. Utilizing microBIOMETER® allows their customers to have a greater understanding of how soil type and management practices impact soil biology and advise them on potential solutions to improve performance.
The microBIOMETER® helps Can Grow and their customers determine a baseline of organisms within an entire field or production area that may be high or low yielding. It allows the company to track the improvements their solutions make on the balance and diversity of micro-organisms in the soil. Microbial systems are often hard for growers to understand because they can’t be seen. microBIOMETER® creates a clear picture by quantifying which solutions work in supporting soil health and which ones do not.
In a bio-fertility trial, ReNew (bacteria/fungi team from Biodyne USA) was applied in furrow with water to corn, Can Grow then evaluated the microbial diversity in the root system of the microbial treated area vs. the non-treated area. The untreated soil had a F: B ratio of fungi 4% and bacteria 96%. This level was much lower than what they wanted for yield optimization. However, it was consistent with what they generally see in tilled, high crop protection use fields. The ReNew treated area had a F:B ratio of fungi 29% and bacteria 71% showing the biology was colonizing the root zone area and providing fertility benefits to the crop.
About Can Grow: The company is much more than a fluid fertilizer company. They have a long, successful history of innovating, adapting and manufacturing fluid solutions to maximize plant potential and soil performance. As a manufacturer, they have the technology and knowledge to innovate and adapt proven fluid solutions to meet changing needs in any market. They assist their clients in addressing factors beyond their control, such as changing environmental conditions, through foliar combinations for application throughout the season.
Find out more at: www.cangrow.com
Our customer Living Water has been utilizing microBIOMETER® to enhance their approach to sustainable farming and to refine their microbial treatments, ensuring they meet the specific needs of each farm.
Their innovative system integrates with the existing irrigation setup to distribute beneficial microbes effectively. With the help of microBIOMETER®’s soil testing, they are able to analyze microbial biomass and adjust the microbial mixes they provide each month, ensuring optimal soil health.
Sales rep Brent taking a soil sample at one of the farms in West Texas
Leveraging microBIOMETER® for Increased Soil Health
Our customer Living Water has been utilizing microBIOMETER® to enhance their approach to sustainable farming and to refine their microbial treatments, ensuring they meet the specific needs of each farm.
Their innovative system integrates with the existing irrigation setup to distribute beneficial microbes effectively. With the help of microBIOMETER®’s soil testing, they are able to analyze microbial biomass and adjust the microbial mixes they provide each month, ensuring optimal soil health.
Key Benefits:
Living Water and microBIOMETER®’s collaboration is the result of their shared passion for soil health and their quest to transform farming with data-driven microbial management.
About Living Water: Living Water is a visionary agricultural technology company with a mission to redefine the way farmers approach soil health. Their flagship product is a subscription-based automated microbe bioreactor that seamlessly infuses essential nutrients into every irrigation cycle. Designed to deliver maximum efficiency with minimal labor, this innovative system eliminates the need for labor-intensive hauling, mixing, or application processes. Learn more at WeSaveSoil.
Drew Hundelt, Horticultural Specialist and Agroecology Practicioner, has partnered with Gibrill Sesay at Central University in Sierra Leone and microBIOMETER® is playing an important role in their work. Central University is a beautifully maintained college campus nestled in the lush tropical surroundings of Tonkolili in the Northern Provence.
Drew first became acquainted with Gibrill through the United States Department of State’s Community Engagement Exchange Program. The two spent some time at The Urban Farm in Denver facilitating agricultural programming for local neighborhoods. Shortly thereafter, their application to the reciprocal grant was approved which allowed Drew to visit Central University as an agricultural specialist in the Spring of 2023.
Utilizing the microBIOMETER®, Drew is currently working with the university on curriculum development around soil health in agriculture. Their most recent trials analyze how the effects of compost extract using soil from termite hills can bring about exponential growth and drought resistance to crops. The students are using the kit to get real time results of how the fungi to bacteria ratio can be a catalyst to real beneficial change.
“I had the opportunity to collaborate on several lectures and practicums for 30 students in the agricultural department. I spoke on the advantages of regenerative agriculture, community-built systems, and biologically driven yields. What struck me the most was the look in their eyes and how their spirit was teaming with curiosity. I knew then, initiated by the financial constraints of affording a commercial soil diagnostic lab, that I needed to get a biological tool into their hands to foster that curiosity. I am extremely hopeful about what the future holds for Central University, small-holder farmers in Sierra Leone, and West Africa at large. ” Drew Hundelt
Holganix utilizes the microBIOMETER® test as a baseline for their customers to see the fungi and bacteria levels present in their soil. These results act as a starting point. Most of the soil initially tested is bacteria dominant. That is what the company is trying to change. The Holganix product used to amend the soil is fungal and protozoa dominant. By increasing these levels, they are increasing the soil health on their customer’s farms.
microBIOMETER® acts as a dashboard or gauge that shows where growers start, where they are during the course of the season and where they are at the end of the season. Holganix uses this information to build a database that records year over year results; with the goal of increasing the biology in the soil.
These two photos from the microBIOMETER® app show one of their check fields vs. the same field with their product. This is an accurate representation of how they like to package the information for their growers.
“microBIOMETER® is a simple to use test that opens the eyes of our growers all across the Midwest. When they see the real time results, they begin to understand how important living biology is for their soil.”
About Holganix: As the only true plant probiotics, Holganix Bio 800+ products contain an entire microbiome or community of organisms that is both abundant and diverse. In a single tote of Holganix Bio 800+ there are more than 800 species of active microbes, microbe food, and nutrient enhancers. Working together, the microbes in Holganix Bio 800+ unlock nutrients already present in the soil and optimize the uptake of nutrients you apply, maximizing nutrient efficiency and minimizing loss. Microbe food helps obtain the rapid establishment of beneficial microbes, while nutrient enhancers work with the microbes to promote strong root growth and healthier plants.
Holganix utilizes the microBIOMETER® test as a baseline for their customers to see the fungi and bacteria levels present in their soil. These results act as a starting point. Most of the soil initially tested is bacteria dominant. That is what the company is trying to change. The Holganix product used to amend the soil is fungal and protozoa dominant. By increasing these levels, they are increasing the soil health on their customer’s farms.
There are many soil tests on the market so it can be difficult for farmers to ascertain whether or not they’re choosing the right one. The truth is, there are pros and cons to every soil test. Therefore it boils down to finding which ones align best with your farming goals and which are easily and readily available to you without needing to stretch your resources too much.
Since microBIOMETER® is a relatively new soil test on the market, a lot of questions are raised on how this test is different from other commonly used soil indicators such as the Haney Soil Test and PLFA test. While all three are soil biological health tests, their methodologies are very different and the tests measure different parameters.
The microBIOMETER® is an on-site soil test that measures the microbial biomass and fungal to bacterial ratio of living and dormant bacteria and fungi. The test process works by measuring the color intensity of the microbial solution created and comparing the color to the test card comparator. This patented, colorimetric analysis process is generated through our microBIOMETER® Reader App and produces results within 25 minutes of starting the testing process. Test prices range from $13.50/sample to $6.75/sample. The low cost, rapid result detection, and on-site testing of living soil are what makes this test stand out against others. The microBIOMETER® has a slightly limited scope, however, as it’s only able to measure the overall biomass of fungi and bacteria. It does not differentiate between microbial species nor does it measure any other parameters.
The Haney Soil Test is a lab test that focuses on assessing a variety of soil parameters such as pH, microbial biomass, water extractable organic carbon and nitrogen, soil respiration, and inorganic plant available nutrients such as NPK. This test uses multiple methods in order to obtain results, including the Solvita CO2 Burst test to indicate soil microbial respiration and biomass, and the use of unique soil extracts to determine organic and inorganic nutrient availability. While this test offers a large array of soil parameters, there is controversy in the science community about using the Solvita CO2 Burst test methodology as a way of accurately predicting microbial biomass. This is because the soil is dried then rewetted to trigger a release of CO2 to measure microbial activity. Drying soil decreases microbial biomass, and while rewetting it will increase biomass again, it doesn’t necessarily repopulate back to the original microbial composition. The Haney Soil test is offered at several labs throughout the country and recommendations are included with results. Generally, this lab test costs about $50/sample and takes about 3-4 weeks to receive results.
The PLFA Soil Test is a lab-based technique that analyzes phospholipid fatty acids (PLFA), which are found in the cell membranes of living organisms, to determine an estimation of living microbial biomass, fungal to bacterial ratio, and to identify the general presence or absence of microbial functional groups in bacteria, fungi, and protozoa. For this test, labs first dry the soil overnight then use multiple solvents to extract fatty acids from the sample. Then, mass spectrometry is used to identify the sample’s microbial composition based on specific PLFA biomarkers. This testing process takes a few days to complete and generally costs about $60/sample depending on the lab. It is one of the most utilized testing methods since it gained popularity in the late 80’s. Since then, it was discovered that some of the PLFA biomarkers used for identification aren’t limited to one microbial group, therefore making it difficult to determine the accuracy of some results.
The value of each of these tests is to determine a baseline assessment of your soil health. The information obtained from any of these tests will help you gain a better and more rounded understanding of what’s happening in your soil.
