Making compost tea

Making compost tea

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Together with sun and sufficient rain, compost tea will help lilac plants bloom. Photo by Ellen Barcel

By Ellen Barcel

Last week, we took a look at compost in general, what it is and how it’s made and used. This week, we’ll take a look at compost tea.

Compost tea is rich in nutrients but will not change the structure of the soil as compost itself will. It brings nutrients to plants quickly, while compost itself is more slow-release with nutrients going into the soil more gradually. Plan to use your compost tea within a few hours after its made.

There are a number of ways to make compost tea, some requiring a variety of equipment. The easiest way is to take a large bucket and fill it with mature compost. Add an equal amount of water and let it steep for a few hours to overnight. Take cheesecloth or burlap and strain the liquid out of the bucket. The liquid can be applied to the soil or used to foliar feed. It is taken up quickly by the plants’ roots. Some people take the compost and put it in a burlap sack and suspend it in a bucket or barrel of water to avoid the straining step.

Some gardeners feel that compost tea needs to ferment and therefore will add molasses to the liquid. The University of Vermont Extension, however, notes that its recommendation is to avoid adding simple sugars like molasses to the mix. It also notes that if the compost tea is made with additives but not tested for safety, then food crops may not be harvested “until 90 to 120 days after the compost tea has been applied.” This is the same recommendation for raw (not composted) manure being added to the garden.

How exactly you go about making the compost tea is up to you, but taking this extra step, while time consuming, gets nutrients into your plants quickly and makes for healthy plants. Healthy plants are more disease and pest resistant. Compost tea can be sprayed on your lawn as well as used for perennials, annuals, shrubs etc.

Remember, a benefit of compost and compost tea that you make yourself is that you control exactly what goes into it. You can totally avoid pesticides and chemical fertilizers if you want. Also, remember to avoid adding diseased plant matter to the compost pile.

If you are interested in making compost tea, there are two excellent, detailed articles from the University of Vermont ( and the University of Illinois ( Cornell Cooperative Extension also has an excellent online brochure on composting in general (

Ellen Barcel is a freelance writer and master gardener. To reach Cornell Cooperative Extension and its Master Gardener program, call 631-727-7850.