Picture billions of microscopic, hungry Pac-Men suspended in water, and you'll begin to understand how compost tea works. When a drop of the tea lands on a leaf, countless beneficial microbes suddenly find themselves at the dining table. They immediately go to work, munching on plant pathogens while out-competing them for space on plant surfaces. They also starve out their competitors by eating up whatever nutrients are available on the surface and emit natural antibiotics and enzymes that kill off certain unhealthy microorganisms. When the tea is used as a drench on the soil, it has a similar effect on pathogens while enriching the earth. The tea is made by putting compost in a filter basket that lets beneficial microorganisms through while holding back larger particles. The basket is then suspended in a tank of water enriched with nutrients, such as seaweed extract and rock powder. Another air diffuser is inserted into the filter basket from the top, which serves to further aerate and mix the compost while it pushes more of the essential ingredients into the solution. Using 45 watts of power (less than a standard light bulb), the system releases 7,000 air bubbles per second through a fine diffusion membrane in the bottom of the tank. This creates optimum levels of oxygen, which along with the nutrients in the water, creates perfect conditions for microbial reproduction. As the tea brews over the next 24 hours, the high levels of oxygen and nutrients help the microbes reproduce at incredible speed. After 24 hours, each milliliter of water contains millions of microbes instead of the thousands it started with. The tea has a shelf life of only 18 to 24 hours because it is so alive. It is generally applied six times over the course of a growing season, at a cost of about $5 per acre for each application. That price includes buying the compost and the nutrients, but not the initial cost of the brewer.
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