Collecting microorganisms from the environment
When is the best time to collect microorganisms?
Microorganisms (microbes) may be cultured at any time
of the year; however, avoid wet, rainy seasons. Excessive
moisture in the environment promotes growth of fungi
that are less desirable for the intended uses.
How time-consuming is it to collect these
The collection process takes approximately 4–5 days in
cooler weather (about 68°F, 20°C) and 3–4 days under
warmer conditions (> 68°F, 20°C).
Where are the best places to collect
Beneficial microbes are highly concentrated under undisturbed
forests or other vegetated areas. Combining
microbes collected from multiple sites will likely result
in a more robust culture.
What collection supplies will I need?
Collection materials are relatively inexpensive and readily obtainable.
• a small wooden box, 12 x 12 x 4 inches deep, preferably
made of cedar
• steamed white rice
• white paper towels, enough to cover the wooden box
• two to four large rubber bands
• a sheet of clear plastic, large enough to completely
cover the wooden box
• 1⁄4-inch mesh wire screen large enough to completely
cover the wooden box.
How are collection supplies assembled?
Fill the wooden box with 3 inches of steamed rice.
Cover the box with white paper towel, being careful
not to let the towel touch the rice. There should
be an inch or so of air space between the rice the paper
towel. Use rubber bands around the top of the box to
secure the paper towel in place.
Cover the top of the box with wire screen to
prevent animals from tampering with the rice. Top the
wire with a sheet of clear plastic to protect the box from
rain, and place it under trees or in another secluded area.
The box should not be in direct sunlight.
Partially bury the box in the soil . It should
be buried at least 2 inches deep for best results.
Cover the box with fallen leaves from the harvest location.
Anchor the plastic sheet on all sides with
small rocks to prevent it from being dislodged by wind.
Leave the box undisturbed for a minimum of 4–5
days. After that time, check to see whether the moist rice
is covered with white mold. If mold growth is sparse,
re-cover the box and wait an additional 2–3 days before
re-checking. If the mold is a color other than white (other
colors indicate growth of less effective fungi) or if rain
has entered the box, the contents should be discarded
and the process repeated.
Culturing the microorganisms
Once the desired microbes have been collected, the next
step is to increase their numbers.
What materials are necessary for culturing?
The basic supplies for microbe culturing are
• a clean clay pot (hard-fired, glazed, or terra cotta)
• a wooden spoon
• white paper towels
• rubber bands
• a large clear bowl, big enough to hold contents of rice
• a small food scale
• a straw mat
• a shovel
• a composting thermometer
• raw, granulated brown sugar
• wheat mill run* or, if available, mushroom growth
*Wheat mill run (WMR), also called “wheat midds” or
“middlings,” is the materials remaining after flour, or
semolina, is extracted from wheat or durum during milling.
WMR generally includes ground screenings from
cleaning; remnant particles of bran, germ, and flour; and
other offal from the milling process.
How are the materials assembled to cultivate microbes?
1) Weigh and record the weight of the large bowl.
2) Use the wooden spoon to move the molded rice from
the wooden box into the bowl. Weigh the
filled bowl and calculate the weight of the rice mass
by subtracting the weight of the empty bowl from the
3) Gradually add an amount of granulated brown sugar
equal to the weight of the rice mass. Handknead
the sugar and rice until the material has the
consistency of gooey molasses. Protective
gloves are suggested.
4) Fill the clean clay pot two-thirds full with the rice/
sugar mixture. Cover it with paper
towel secured in place with rubber bands.
5) Store the pot in a cool area away from direct sunlight
for 7 days. This will allow the mixture to ferment.
6) Working in a shaded area, add a small
amount of water to the fermented rice mixture in
a 1:500 ratio. Then, slowly blend in wheat mill run
(or used mushroom medium) until mixture is of
semi-moist but not wet consistency (roughly 65–70%
7) Place a mound of the mixture on a soil surface and
cover it with the straw mat or leaves, protecting it from
sunlight. Allow the microbes to propagate
for 7 days. Periodically examine the external surface
of the pile for white mold growth, monitor internal
temperature of the pile with a composting thermometer
so as not to exceed 122°F (50°C), and turn the
pile with a shovel (a minimum of three to four times
during the week) to keep fermentation temperatures
from getting too high.
8) When the fermentation process is finished, internal
temperature will stabilize, indicating cultivation is
finished. Your culture of naturally occurring microorganisms
is now ready for use
What do I do with the fermented mixture?
Dilute the final product (1 to 1 by volume) with soil and
incorporate this mixture into the surface soil as a topdressing
for crop production, or add it to your compost
pile. This biological soil amendment is expected to enhance
soil microorganism activity.