Compost Tea


by Karen Weiland, Advanced Master Gardener



Any gardener worth his or her salt knows the many benefits of a good compost.  But what about this stuff called compost tea?   Well, it is something you can use on your plants as a foliar application or as a soil drench and it’s a way to give your plants a healthy boost and it 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  or length of panty hose, with about 3 cups of some finished compost in it, in a 5-gallon bucket of water for up to three days.   Move the bag around in the water at least once a day by dunking it like you would a regular tea bag.   Strain the tea, pour it into a hand-pump sprayer and spray it on plant leaves.   The compost “tea bag” can be used several times with this method and you can use this tea on plants every two weeks. 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’ lengths of aquarium hose attached to a multi-stemmed gang valve hung on the rim of a 5-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.


As always Happy Gardening!


More information about gardening and related subjects is available online at  The Purdue Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.