Monthly Archives: February 2015

Actively Aerated Compost Tea



One teaspoon of soil has 1 billion bacteria, 1 million fungi, and 10,000 amoebas, protozoa, and nematodes. These critters are vital to maintaining a healthy soil. Commercial fertilizers are salt based, and poison the soil. Once the soil dies, you need to constantly feed your plants to keep them alive. The plants become dependent on the added fertilizer.


A more sustainable solution is to feed the soil, not the plants. If you have healthy soil, the plants will get all the nutrients they need from the soil. There are many teas that will help you feed your soil. This post features a super brew called actively aerated compost tea.  It is very simple and inexpensive to make and it works wonders.  There are many recipes for it. This one is adapted from an article by Diane Kennedy on and a class in Soil Alchemy that she conducted in July of 2013.

You will need a 5-gallon bucket, a paint strainer or cheesecloth or an old sock, a fish tank aerator or air bubbler, and some organic unsulphered molasses.


Fill the bucket with either rainwater or tap water. If the water contains chlorine, let it sit at least a day or aerate the water for 1 to 3 hours to allow the chlorine to evaporate.


Take the paint strainer and fill it with samples of good soil from around your property.  If you don’t have any good soil, then add the best you have and then take good soil from areas as close to your property as possible.  If you will be using the tea on bushes and trees, then be sure to take soil from under the same.  Woody plants  like highly fungal soil.  If you will be using the tea for annuals and veggies, then go heavy on fine, well-composted soil that is bacteria-rich.  Do the best you can; you can’t go wrong unless you take soil that has been sprayed with chemicals, use treated wood chips, or anaerobic soil (you’ll smell it if you do).


Place a stick or pvc tube across the top of the bucket, and tie the top of the cloth to it with twine so the the soil is suspended in the water.


Place the aerator or bubbler in the bucket, making sure the air intake hose is clear, and plug it in. An aerator with two outlets provides a better distribution of oxygen


Add about a tablespoon of molasses.  It is important that the molasses is unsulphered and organic for the same reasons that the water shouldn’t have chlorine in it or the soil any chemicals: those things will hurt the microbes that you will be growing.  For growth of other microbes, add about a teaspoon of any or all of the following: organic cornmeal, organic wheat flour, liquid kelp, and if you have it tucked away in your shed, bonemeal and bloodmeal (otherwise don’t buy it specially!).


Allow the aerator to do its thing for about 13 hours.   The micororganisms in the compost will feed on the molasses and oxygen, reproducing until at about 13 hours their numbers will peak and begin dying off a little.  The tea should be used within a couple of hours.


What this tea is doing when applied, is establishing or boosting the fungus, bacteria, amoebas, nematodes, and other soil inhabitants in your dirt, all of which are native to your particular area.  If you have decent soil already, then you can use this tea 1:10 parts dechlorinated water.  If you have rotten dirt, use it straight along with a topping of compost.  Compost, whether it be cooked composed compost, straight leaf matter, shredded wood, logs, damp cardboard or natural fabrics, all provide shelter and hold moisture in so that your microbes have habitat.  Compost, of course, is the best source of food, moisture and shelter for them.


Apply the tea with a watering can, or a sprayer that has a large opening for the nozzle if you are using the tea as a foliar spray.  A squeeze-trigger bottle used for misting has too narrow an opening and will kill a lot of the little guys you have just grown.


Using the tea as a foliar spray will treat disease, fungus and nutrient deficiencies, and help protect plants against insect attack.  Instead of spraying sulfur or Bordeaux solution on your trees as is preached by modern gardening books, use compost tea on the leaves and around the drip line. When applied to leaves, the plant’s exudates hold the beneficial microorganisms to the stomata or breathing holes protecting them from disease and many harmful insects. You can’t overdose with compost tea.


All the additives that are recommended to ‘improve’ your soil are bandages not solutions.  Think of the billions of soft-bodied creatures living in your soil, waiting for organic matter to eat.  Then think of the lime, the rock dusts, the gypsum, the sulfur, the NPK concentrated chemical fertilizers (even derived from organic sources), poured onto these creatures.  It burns them, suffocates them and kills them.  Your plants show some positive results to begin with because they’ve just received a dose of nutrients, both from what you applied and from the dead bodies of all those murdered microbes.  However the problem still is there.  The only long-term solution to locked-up nutrients in the soil, hard pan, heavy clay, sand, compaction, burned, or poisoned soil, is good microbe-filled compost.  Remember that microbes turn soil into a neutral pH, and allow more collection of neutral pH rainwater.  Nutrients in the soil all become available at a neutral pH; there is no such thing as an iron-deficient soil.  The nutrients are just locked away from the roots because of the lack of microbes and the pH.