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Knowledge to Grow by Karen Weiland - Compost Tea

Any gardener worth his or her salt knows the many benefits of a good compost. But what about this stuff called compost tea? Compost tea is not something you will want to be sipping from your teacup on a relaxing afternoon. It is something you can use on your plants as a foliar application or as a soil drench. It’s a way to give your plants a healthy boost and is a wonderful soil tonic.

Compost tea is defined as a liquid extract of compost that contains plant growth compounds and beneficial microorganisms. It is basically made by soaking, steeping or brewing finished compost in a container of water.

While there are a variety of processing methods to be had, the most simplified method is to soak a burlap bag of finished compost in a five-gallon bucket of water for a designated length of time. It is best to use de-chlorinated water to maintain microbial life. To de-chlorinate water simply store it in an open container for several hours, the chlorine will naturally dissipate.

The most recent concept of aerated compost tea is made by incorporating aeration technology to create optimum levels of oxygen for growth and reproduction of those wonderful beneficial microorganisms. A simple way to introduce air would be to use several 12 ft. lengths of aquarium hose attached to a multi-stemmed gang valve hung on the rim of a five-gallon bucket. Make sure the hoses reach the bottom of the bucket. Add finished compost making sure the ends of the hoses are covered. Add water to within 6” of the top of the bucket. Add 1 oz. of unsulfured molasses to provide a food source for the beneficial microorganisms. Turn on the aquarium pump and let this mixture brew for a couple of days, giving it a few stirs now and then. When finished brewing, strain the mixture using cheesecloth. The tea should smell sweet and earthly. If it doesn’t, do not use it on your plants. Pour it onto your compost pile. Use it right away, as the oxygen will be used up and the tea will turn anaerobic, thus killing the beneficial bacteria.

The issue of food safety needs to be taken in to account when using compost tea. Gardeners should follow the recommendations of the National Organic Standards Board’s compost tea task force (on the web at More information about compost teas can be found at

As always Happy Gardening!

The Purdue Cooperative Extension Service can be reached at 499-6334 in LaGrange County.