What is Compost Tea?

making compost tea

Compost Tea Is For Plants, Not For People

When you first heard of compost tea did you think, This time the organic gardeners have gone too far? Tricia has a story about that in our video on compost tea for home gardeners. To be clear: compost tea is for PLANTS not people! Special solutions of garden "teas" have been around for centuries, but the latest technique of aerating compost tea is relatively new. It's an increasingly popular way to create a soil inoculant. Let's define the different garden liquids, including aerated compost tea.

Manure Tea

Longtime gardeners remember manure tea. That was made by taking a hunk of manure, wrapping it in a piece of burlap or cheesecloth, and suspending it in a water-filled drum or watering can. After soaking for several days or weeks, the manure bundle was removed and the watery solution poured on a beloved plant. Famed illustrator and old-fashioned gardener Tasha Tudor swore by this for her peonies. There are concerns about the levels of E. coli that live in manure tea, persist in the container, and can be transported on to edible plants.


Leachate is the liquid that oozes from the base of a compost pile. This is NOT compost tea. It is a byproduct of the composting process and if it occurs before the compost process is complete, the leachate may contain harmful pathogens. Do not use this as you would compost tea.

Worm Juice or Worm Leachate

The liquid that comes out of a worm-composting bin. Many gardeners put it directly on the soil around their plants.

Traditional Compost Tea

Traditional tea is made the same way as manure tea. Also referred to as Non-aerated Compost Tea [NCT], it relies on the passive interaction of the compost and the water. A chunk of compost is soaked for a period of time in a container of water, and the resulting extract is NCT.

In our video Tricia demonstrates how to make Aerated Compost Tea [ACT] in our compost tea brewer. She uses Arctic Humus (you can also use finished compost or worm castings), a catalyst, and chlorine-free water -- all bubble together in our brewer for at least 24 hours. The theory behind the aeration and the use of a catalyst is that they aid the growth of the beneficial microbial populations in the tea.

The brewed ACT can be used as a soil drench; when used as a soil drench, compost tea should be applied so that it moves into the root zone. This can be accomplished by following the tea application with additional water. Use full strength or dilute 1:1 (tea to water) for indoor houseplant and garden plants. Drenching a medium size plant requires about 2 cups of tea plus enough water to get the solution down to the roots.

The OSU Extension also suggests that the ACT can be administered by FOLIAR FEEDING (spraying on the leaves): ACT can be applied to the soil or directly to the plant as a foliar spray. When it is used as a foliar application, it is best to strive for thorough leaf coverage using a fine mist. Foliar applications are best done early morning or pre-dusk to minimize the effects of UV rays.

Are you ready to boost your soil and your plants with a dose of ACT?

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