Making Aerobic Compost Tea

Yantis Lakeside Gardens -

Living and Gardening in the Beautiful Texas Hill Country

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How to Make Aerobic Compost Tea

How to Make Aerobic Compost Tea

by Sheryl Yantis, Master Gardenerby


5-gallon bucket

Small Aquarium air pump

Plastic tubing

Aquarium Aerator-stone


1-4 cups compost

Fill a 5-gallon bucket about ¾ full of water. If you use treated water, let it sit for 24 hours or run the air pump for 10 minutes to get the chlorine out. Place pump on the ground, or somewhere near the bucket. Attach plastic tubing to the connection on pump. Place other end of tubing on the connection on the aerator. Place aerator in the water on the bottom of the bucket, and plug in the pump. You will see bubbles in the water when pump is working.

Take piece of cheesecloth and put compost inside and tie ends. You can put the cheesecloth in the bottom of the bucket or tie it to the handle. It really doesn’t matter as long as the compost is in the water. You can even put the compost in the bottom of the bucket. The reason for the cheesecloth is to keep the larger pieces of compost from getting in the tea.

Let the pump run. The amount of time the pump runs determines the strength of the tea. The optimum length of time that the tea should be brewed can vary. Most sources indicate that the tea should be brewed from 24 to 36 hours. If you brew the tea longer than 24 hours you must feed the microbes or they will starve. I usually put some agricultural molasses and seaweed in mine in case I don’t get back to it in time. I put a little more in at about 24 hours. You can use only molasses if you want. If you brew it less than 24 hours it will still have microbes in it, it will just not be as strong.

You must use the tea within 2 hrs after you stop aerating it. If you do not use the tea right away the microbes will die.

If you use the tea in a sprayer you will need to strain the tea so that your sprayer will not clog up. Too much pressure such as in a hose-end sprayer may harm the microbes. If you use the tea in a watering can you may not need to strain the tea.When you get to the bottom of the bucket of tea just throw whatever is left on the ground somewhere you want some microbes.

Clean everything with a 9 parts water and 1 part bleach solution after each use to avoid contamination. You can do this by putting everything except the pump in the bucket with some of the bleach solution and running the pump for a few minutes

There are two types of compost tea.

Bacterial compost tea is made from composted manure - steer, chicken, etc.

The microbes produce nitrogen so it is good to use on lawns or early in the year in the garden when you want to promote growth.

Fungal compost tea is made from non-manure compost such as cotton burr, etc

The good fungus attaches to the roots and helps the plants root system. It is good to use in the soil around plants, trees, shrubs and in the garden to promote vegetable production.

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