Compost Tea

There is some controversy surrounding the making and use of compost teas. Some say that when applied to the leaves of a plant they can be an effective way to deliver nutrients and control plant diseases. Others claim that due to the varied composition of compost that there is little scientific proof that they achieve any significantly increased benefits to overall plant health when applied in this method.

Nutrients can be extracted from compost by various methods. The simplest takes compost and steeps it in water for a week or two. The compost may be suspended in a bag or nylon hose, or just placed in the water. The resulting extract consisting of soluble nutrients can be fed to plants. The next level of complexity involves using aeration methods and a food source to feed the microbes that live in the compost and enable them to multiply. Aeration can be achieved by several methods but the simplest for the home gardener is an air-stone connected to an aquarium air pump with a length of tubing. A five gallon bucket is filled loosely about half way with compost and water is added until the bucket is about 3/4 full. Then add an ounce or two of a convenient food source such as molasses. This mixture is "brewed" for 24-36 hours and should be used immediately. Herbal teas may be made by filling a large container 3/4 full with fresh plant material and filling the container full with warm water. The plant material is left to ferment for a week to ten days. The liquid is strained and diluted one part tea to 5 to 10 parts water and applied to the foliage or the roots. If you go this route place the container away from the house and the neighbors, it can develop quite an aroma.

A word of caution about the making and use of this product is in order. Compost containing animal manures should have been properly composted so that the internal temperatures of the compost pile reach temperature sufficient to kill any pathogenic bacteria. This is especially important when applying the tea to foliage and fruits. As making compost, especially in a home setting, is a less than scientific undertaking, we recommend that you limit your use to soil application. If you wish to experiment with using them in a foliar application, limit it to composts made exclusively with plant material or one of the herbal teas mentioned above.

There are a number of compost tea brewers available commercially. For the average home gardener, it is our opinion that these are not cost effective items to purchase and maintain and that compost teas can be produced with simple equipment that can be found around the home or purchased inexpensively.

The Compost Tea Brewing Manual is a book by Dr. Elaine Ingham. This book is recognized as one of the most complete books on the subject.

A publication from which some of the information above was obtained can be downloaded from the National Sustainable Agriculture Information Service at-

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