"If we want clean water, we have to get the biology back in our soils. If we want to grow and harvest crops, we have to build soil and fertility with time, not destroy it. The only way to reach these endpoints is to improve the life in the soil." - Dr Elaine Ingham, Founder of Soil Food Web, Inc.
Compost tea: a simple solution, with a very complex foundation. At the surface, making compost tea is as easy as mixing a handful of your favorite compost, earthworm castings, and a little molasses in water, and providing a source of airflow. Easy and simple right? But inside that simple solution of bubbling liquid is a complex society comprised of billions of microorganisms, eating and multiplying within hours of starting the tea. Contained in 1 teaspoon of healthy compost you could find up to a billion bacteria, several yards of fungi filaments, thousands of protozoa, and heaps of nematodes. Developing this microbiome is the goal of brewing compost tea. These organisms will work symbiotically together, as well as with the roots of your plants.
Why do these microscopic beings have such an important role in organic cultivation? These microorganisms are the decomposers of organic matter. As they decompose organic matter, nutrients in the soil are released in their digestible form, which are then easily absorbed by your plants. While most compost or earthworm casting teas will contain small amounts of nutrients in them, the real benefit comes from the unlocking of nutrients already in the soil.
Roots essentially trade food for food with microbes. When plants photosynthesize they create and exude sugars, carbohydrates, and proteins through their root systems which feed the microbes, while the microbes provide micro and macro nutrients for the plants in exchange. Without these exchanges, roots wouldn’t be able to absorb all that kelp meal, alfalfa meal, or soybean meal that you've amended your living soils with. Without the microbes, the roots of your plant will be staring at a buffet of fine foods with its mouth sewed shut.
In addition to providing essential nutrients, the microbes in compost teas will supply your soil and roots with a “medical" and “police” force to keep the ecosystem in balance. A properly brewed compost tea will not only reinforce the strength of roots, but also regulate the balance of beneficial microbes, to ensure they out-compete the parasitic ones. For example, root-feeding nematodes, a parasitic microbe, can cause your plant to inexplicably begin to yellow, stunt its growth, and cause a grower to ponder what nutrient deficiency their plant is experiencing. If you supply your soil with enough beneficial nematodes to out-compete the malicious ones, you’ll see a boost back towards health in a short time.
Not all compost teas are created equal. With just about anything in life, if you start with premium inputs, your output will be a high-quality product as well. If you start with unfinished compost and low quality amendments, don’t expect impressive results. If you choose to make and use your own compost I would highly recommend investing in a microscope class. This will enable you to observe the balance of bacteria to fungi in your mix, as well as spot any parasitic microbes which may have proliferated in your composting process.
Homemade compost is by far the cheapest (and best way to re-use food scraps and yard waste for free!). It can also provide the best results, but does take effort to create. If you don’t have the time or energy to make your own compost, go to a local organic gardening store and ask them for their best quality. In Southern Oregon, for example, we found a local health food and garden supply store called Takubeh that makes a great selection of different composts.
If you don’t have a local composter, our favorite bagged composts are Oly Mountain Fish Compost and Malibu Compost’s Bu’s Blend Biodynamic Compost. Both are highly regarded, and considered the industry’s best and most biologically active composts available (and if you’re lucky you’ll get heaps of worms and beneficial soil mites as an added bonus!!) When choosing the amendments and other inputs, don’t skimp on quality because of the price. Think of it as an investment in the medicine and food you choose to ingest.
“Compost tea” is a general term that could describe a recipe as simple as the ingredients I mentioned above, or a more complex, highly supplemented brew. Compost tea can be supplemented with just about any dry amendment, a handful of leaf litter, a handful of mycelium-covered bark, or any other plant materials you have access to. A company called DragonFly Earth Medicine from Oregon, creates compost tea blends that include: ground comfrey, nettle, kelp, wild yam, alfalfa, horsetail, turkey rhubarb, burdock root, cocoa beans, cane sugar, humic acid and azomite (which stands for A to Z Of Minerals Including Trace Elements - fun fact!). Now that’s a super- charged blend of medicinal herbs, and a lot more complex than adding a handful of compost into a tea bag and aerating it. Other companies use less ingredients in their blends such as Build-A-Soil who utilize: multiple compost sources, kelp, comfrey leaves, fishbone meal, gypsum, bio char and neem seed cake, to make their high quality compost products. Whether the recipe is simple or complex you will achieve amazing results, but your choice will be guided by your desired outcome.
BREWING COMPOST TEA
When brewing a compost tea, you are limited only by the parameters of your desired outcome and your creativity. For example, if you are looking to create a bacterial-dominated tea, be sure to add a simple sugar source such as molasses. If you’re trying to create a fungal-dominated tea you’ll need to add a more complex food source such as fish hydrosolate. If you are looking for a tea meant to boost flower production use ingredients high in phosphorous such as high-phosphorus bat guano.
So, how do you brew one of these teas? As aforementioned, you can make a simple tea:
SIMPLE COMPOST TEA RECIPE
\ 1 cup earthworm castings
\ 1 cup compost
\ 1 tablespoon unsulphured black strap molasses
\ 4 gallons water
DIRECTIONS: Add the earthworm castings and compost to a compost tea bag. Add the tea bag, molasses, and water to a 5-gallon bucket. Place two air stones connected to a fish tank air pump in the bucket. Let the tea brew for 12-48 hours.
Picture credit: https://www.greencultured.co/organic-cannabis-nutrients-teas/
You can experiment with mixing your own blend of composts and amendments together and test for your desired results, or you can google such links as buildasoil.com ,kisorganics.commakeorganicsoil.com ordragonflyearthmedicine.comto read what they put into their blends and mimic their recipe. One of my favorite teas to make for my cannabis plants during the vegetative stage is a simple recipe provided by Tim Wilson of microbeorganics.com:
COMPOST TEA FOR VEGETATIVE PLANTS
\ 1-2 cup alfalfa meal
\ 2 tablespoons kelp meal
\ 2 tablespoons molasses
\ 4 gallons water
DIRECTIONS: Add the alfalfa meal and kelp meal to a compost tea bag. Add the tea bag, molasses, and water to a 5-gallon bucket. Place two air stones connected to a fish tank air pump in the bucket. Let the tea brew for 12-24 hours.
Even without the addition of compost, this simple recipe will feed the microbes already present in your soil and help them proliferate. The alfalfa has loads of natural plant growth regulators, promotes the growth of flagellates and amoebae, and is a fungal food. The kelp provides an array of hormones and trace minerals to create explosive growth in your plants.
Not only are compost teas the best thing you can feed your living soil, but you will be saving yourself a lot of money by not purchasing over-priced bottled nutrients. Most of the bottle nutrient companies spend more money on marketing and creating flashy labels than the actual products themselves. These bottles can run you hundreds of dollars every cycle and that adds up quickly when considering the production costs as well. A square foot of compost generally costs between $10-$20 and can be used to make weeks’ worth of quality food and medicine for your plants.
So skip the bottled nutrients and start brewing compost tea. Not only will you be saving yourself money, you will know exactly what you are putting into your plants and allowing your plants to fully express their true genetic potential. Organic amendments are great but only if you have the microbes in the soil to cycle them. Whether you choose to make your own tea or buy a pre-made recipe you’ll receive an abundance of benefits for a small amount of money as compared to bottled nutrients. So just remember, when you focus on feeding the soil you are building a healthy microbiome that will support your plants for years to come. Happy growing everyone!