Compost Tea

First, what is compost tea, and why is everyone raving about it? Compost tea is the controlled extraction of microorganisms and nutrients from a small amount of high-quality compost (and additional nutrient sources) into water.

"I gave my starving zucchini some compost tea before I went to bed last night. I woke up to find them perky and very happy looking. Amazing!"Holly

The water is aerated to vastly increase the extraction of microbes, and to provide an environment which will breed many more microbes, favouring mostly those that thrive in an aerobic environment.

The tea is then sprayed on the soil and plants in order to inoculate the landscape with these beneficial aerobic microorganisms. It's not a fertilizer, but provides many of the same benefits and more.

Compost tea is especially important when there isn't enough good quality compost around for your lawn and organic garden. Also, compost cannot be applied to plant leaves, but compost tea can. The benefits are immense.


Compost Tea Brewer

Compost Tea Brewers

I am selling the two excellent 5 gallon brewers from Keep it Simple (KIS).

I started using the KIS compost tea brewer in 2005, since they were (and still are) highly regarded in the world of compost tea and endorsed by Elaine Ingham of the Soil Food Web.

Brew Kits

Brew Kits

The 5 gallon compost tea makers come with one brew kit to get you started. Additional kits are available. Each brew kit contains one mesh bag of compost and one plastic bag of microbe foods. Tip: The mesh bag can be washed and reused!

I carry the same kits as Keep It Simple, but I've substituted a combination of high-quality composts (worm compost and garden compost) that are produced locally.


Compost Tea Application

This video on making compost tea comes from Phil's Smiling Gardener Academy where he has an additional 10 videos on compost tea and 30 or so other videos on effective microorganisms, mycorrhizal fungi and other microbial inoculants.


Brewing compost tea is easy. The brewer comes with instructions. Compost tea can be applied from a watering can, sprayer, or irrigation system. It is applied as a both foliar and a soil drench. It is important to use water that has no chlorine.

Like most liquid products, it is best applied in the morning, while evening would be the second choice (this is particularly beneficial for living inoculants, since some of the microorganisms are not interested in basking in the hot sun, so it's nice to give them some time to acclimate to their new surroundings and find a place where they are happy).

Compost tea works best when combined with liquid organic fertilizer products (click on the 'Organic Fertilizers' link at right to learn more). Preferably, it would be applied in smaller, regular doses, such as monthly or even weekly during periods of stress/disease. At minimum, it should be done once in the spring and once in the fall.

When pouring the finished tea into the sprayer, be sure to put a clean cloth (such as nylon, silk, cotton) over your sprayer to filter out particulate that may cause clogging.

As a foliar, it is applied undiluted, generally at 5 gallons (US) per acre (1/2 Litre per 1000 sq ft) for each 6 feet of average plant height. So if you have an orchard of 18 foot tall trees, you would apply more like 15 gallons per acre.

It is important to spray both the top and underside of the leaves and obtain at least 70% coverage. A mist (not too fine) from a sprayer works best for this. The whole plant can be sprayed.

For a soil drench, as much as 20 gallons (US) per acre (2 Litres per 1000 sq ft) is often applied once or twice a year. This can be mixed with any amount of dechlorinated water as is necessary to provide adequate coverage.

In summary:

  • Foliar - undiluted - 1/2 Litre per 1000 sq ft on all leaf surfaces to at least 70% coverage, monthly if possible
  • Soil - diluted as necessary - 2 Litres per 1000 sq ft, in the spring and perhaps fall

Compost Videos

Here are some videos through a microscope of vermicompost I have used in the past in my compost tea brew kits. They were made by Tim Wilson, who has more longer, narrated videos on his website, www.microbeorganics.com.