The importance of microbial populations in your soil is crucial for many functions surrounding plant growth. In organic cultivation systems, beneficial microorganisms are the foundation of nutrient cycling and nutrient uptake. Inoculates are not all made equal. Microbial density and diversity of bacteria, protozoa, and fungi are how we differentiate between what is quality and what is potentially a source of pathogens. My favorite source of beneficial biology is the castings, or excrements, of worms. This can be described as Vermicompost as well as earthworm castings. Vermicompost is a mixture of castings, broken down organic matter, and organic matter not easily broken down. Earthworm castings are only the castings of worms. Both are the byproducts of Vermiculture. Vermiculture is a safe, effective, scale-able, and environmentally friendly way to turn organic matter and organic waste into a potent source of nutrients and biology. Both of which are crucial to the processes within the soil food web. The vermicompost we are using today is Biovast by SDMicrobes.
What is the soil food web? How does it work? Why does it work? How can we support soil life to complete its processes and further make nutrients available to our soil? These are all complicated questions. I’m going to do my best to summarize them quickly for you. In many circumstances, nutrients in the soil aren't readily available to plants. The chemical forms they exist in require covalent bonding with other compounds to change form and be up-taken by roots. This can be done with several different processes. One is through secondary metabolites exuded by roots, such as carbon sources like amino acids, carbohydrates, proteins, and enzymes. The other is with the presence of bacteria consuming the organic matter that contains nutrients and altering its chemical form. This process is similar to the same process by root exudates because bacteria use similar compounds as root exudates to break down the same organic matter. Those compounds are then stored inside the bacteria and need to be consumed by protozoa to then release them in a form that can be up-taken by roots. Protozoa are the first animals, microscopic creatures that prey on bacteria and eat organic matter. Soil protozoa include naked amebae, testate amebae, flagellates, ciliates, microsporidia, and sporozoans. So far, about 1600 species have been recorded from the soil, many of which have special adaptations to the soil environment. Some bacteria do not need to be consumed by protozoa to be utilized by the plant. These are called endophytes, bacteria that become part of the cellular structure. Bacteria consume organic matter full of nutrients, and protozoa consume bacteria and unlock those nutrients within their excrement. There are other processes that make nutrients available. This process is called chelation. many forms of compounds are also chelated by humic and fulvic acid. These are carbon chains that bond and alter the form of nutrients to be untaken by plants. Earthworms are exceptionally good at creating lots of humates in their castings. The form of organic matter created within the worm’s gut microbiome is easily broken down by bacteria that create tons of humates. Soil science can be complicated, and we are still scratching the surface regarding how it functions.
Within this blog were going to go over nurturing the process of bacteria changing chemical compounds into their readily available form. We will accomplish this by topdressing vermicompost and watering in an aerobic fermentation of vermicompost that has been tailored to contain a population of protozoa. To move forward with properly implementing this technique, an understanding of soil biology and a microscope is needed. I'm going to do some of the heavy liftings for you and show you day-to-day how the diversity of an aerobic fermentation of vermicompost changes. This particular aerobic ferment is typically called compost tea. Compost tea is made by filling a vessel with water, which acts as our medium for biology to multiply. We then add an inoculant. This time we are using Biovast by SDMicrobes. An agitation source is integrated to expose as much surface area of the inoculant as possible. The tea needs to remain aerobic, or full of oxygen. So typically our agitation component is also our aeration component. I like to use a cone bottom tank to brew compost tea in. this allows me to pour my BioVast into the vessel, connect an air pump to the base of the cone bottom tank and let it agitate and oxygenate the compost tea. Next, we add our food sources which can be any form of energy for bacteria. Monosaccharides, disaccharides, and polysaccharides, are all foods for microbes, these are all forms of sugars. Find a form of energy for your tea. In this tea, I used oat flour and red beet. Oats are rich in beta-glucans and red beets are rich in inulin, both are polysaccharides and are amazing bacterial and microbial energy sources.
Once my inputs are all combined within my vessel I let it ferment for 24 hours. After observing the microbial life with my microscope I see that bacteria are starting to multiply. I use 400x magnification to observe this. While this is a good sign, our tea is not ready yet. I observe it again under a microscope 48 hours from the brew start. I see early lower-fungal bodies starting to form. These are not fruiting fungal bodies, as fungi will not truly form mycelium in water. Rather they are non-septated fungal hyphae that have not started to show their true characteristics with maturation. Bacterial chaining is also observed. This occurs when bacteria reach a high microbial density. the bacteria start to form organisms in the form of these chains. It's a good sign of a healthy ferment and a quality inoculant. BioVast for the win. 72 hours in we see that the protozoa have shown up to the party. When the microbial density reaches a certain point the protozoa show up to balance out the numbers. Protozoa cover the entire planet. They are on everything. Literally every single non-sterile surface on the planet. They hibernate in what’s called a “cyst”. This protects them from harsh environmental conditions. They form these cysts from lipids within their cell wall. Their presence in soil is unavoidable, but their numbers will only reach optimal levels with proper conditions. Either organically in nature through proper temperature, oxygen levels, and moisture, or with the help of us soil nerd humans. The time required for protozoa to start being active and multiplying depends on several conditions, temperature and moisture being the two most influential. Protozoa are aerobic organisms, they require oxygen to live. Too many in an environment can cause a depletion of dissolved oxygen resulting in anaerobic conditions. An easy way to prevent this is with the use of a dissolved oxygen meter.
I decided to add aloe vera to the end of the brew. Aloe Vera is a great source of salicylic acid, acemannan, and 19 of the total 20 amino acids. This makes it an incredible plant and soil additive. I don’t want some of the fragile compounds to be altered by the brew, so adding it post-ferment is ideal. Acemannan is one of the best microbial food sources on the planet. A polysaccharide that feeds a huge range of bacteria quickly and effectively. It also contains medicinal applications and promotes metabolic pathways in the plant. Salicylic acid boosts the immune system of the plant. Making it more resilient to pests and pathogens. Amino acids are the building blocks of life the wider the diversity the more types of proteins can be built. These proteins serve a massive range of functions. The combination of biology and chemistry in this mixture makes it a powerful tool in your garden.
Proper nutrient cycling and nutrient uptake are dependent on established and thriving biology. Vermicompost like BioVast is a fantastic way to introduce and maintain thriving biology in your living soil. By adding it to your soil, topdressing it on the surface of your pot, or multiplying it in a compost tea you are forming a partnership with microbial life and nature. With a quality inoculant that is full of biology, you will see improved health, vigor, and growth in your garden. BioVast by SdMicrobes is a quality inoculant. It will provide a foundation for success in your garden. Now go nurture some life!
Written by Luna Whitcomb