Aug. 16 column: Compost tea

August 16, 2015 Susan

Here’s a link to my column in today’s edition of The Spokesman-Review: Compost tea seems worthy of a toast. (or you can read my column lower in this post)

This one is about the benefits of using compost tea and compost extract. It was hard to say everything I needed to say in 600 words! Thank heavens for this blog. I can give you additional information without any worry regarding my word count.

On Aug. 8th, I went to a compost tea demonstration given by Master Composter and WSU/Spokane County Master Gardener Ryan Herring. It took place at Northwest Seed & Pet. The talk was very informative and gave me a lot of ideas.

Here is additional information that I learned from Ryan:

1. In my column, I described the supplies needed for a simple system. I didn’t have room to discuss Ryan’s set-up for the aerator. He uses a large pump and attaches it, via plastic tubing, to PVC pipes. “My air-lift system pulls water through the 1″ PVC pipes. It provides two times the air because it is both pulling the water up through the pipe and the water breaks the surface tension in the bucket. That’s because the pipe is a couple of inches above the surface of the water.” (see photo above)

Also, you can get as fancy as you want if money is no object. Commercially-produced compost tea systems are also available. I primarily focused on a simple system.

2. “Compost needs to be well-broken-down and have a lot of biology in it.” (so be sure to use good-quality compost!) Compost has been produced in this area is an option. But it’s better to make your own because then you know what’s in it.

3. Ryan explained how some plants do better with different types of teas. Most Brassicas (crops like broccoli, cabbage and cauliflower) prefer tea with a lot of bacteria in it. Most other veggies and grasses do better with tea that has a moderate amount of bacterial activity in it. Other plants (such as berries, deciduous and coniferous trees) prefer tea with a lot of fungal activity in it.

How to create bacterial or fungal compost tea

To create a more bacterial compost tea, you would add a microbe “food” like fish emulsion or worm castings. To create one that is more fungal, add in ground oatmeal, powdered malt or soybean meal. Ryan told me that fungus likes a dark area to grow. He moves it to his basement for 4 days, after adding the microbe food and catalyst to the compost. He mentioned how you’ll see white fuzzy growth in the compost. That’s due to the fungal activity so don’t freak out!

Ryan also pointed out that Eastern Washington soil tends to be higher in bacteria than fungi. He feels our goal should be to make compost tea with more fungal growth.

Last but not least, there are some businesses that sell packaged compost tea. Know when it was made. Ryan says it has a very short shelf life when it’s been sealed in a container.

Compost Tea garden column:

by Susan Mulvihill

Have you heard about compost tea? It’s all the rage these days.

Simply put, compost tea is made by steeping good-quality compost in a bucket of water to extract microorganisms to feed your soil. This technique has been used agriculturally for centuries. A more recent development is the addition of an aerator. That will provide a high-oxygen environment in which microorganisms will thrive and reproduce.

Master Composter Ryan Herring is convinced compost tea makes a huge difference. He recently demonstrated how to make it at Northwest Seed & Pet’s store on Sprague.

Here’s what I learned:

In addition to compost tea, there is compost extract. The former is applied to plant foliage to add nutrients. It also improves its ability to resist foliar diseases such as powdery mildew. Apply the latter directly to the soil to increase its biological activity and diversity.

Making tea and extract requires the same general equipment, but the techniques vary.

“The difference between the two is what I put into the compost and the brewing time,” Herring explained.

Compost tea supplies

Supplies for a simple system include a clean 5-gallon bucket, 2 to 5 pounds of finished compost, a burlap or mesh “sock” to put the compost in (think of it as your tea bag), an aquarium pump, tubing, aerator stones and 4 gallons of non-chlorinated water.

Municipal water often contains chlorine which will kill microorganisms. To make chlorine dissipate, let the water sit in an open bucket for 24 hours before beginning the compost tea or extract process, or run the aerator in the bucket of water for one hour. Follow the same procedure for softened water. Water from a well can be used right away.

The process of making it

To make extract, place the sock of compost into the bucket and knead the sock for one minute. Turn on the aerator and let it run for one to two hours. Herring then strains the bucket contents using a paint strainer to remove the solids that could clog a sprayer. Microbes will die off quickly due to lack of oxygen and food. Place the strained liquid in a clean sprayer and apply it to plants as quickly as possible.

Making compost tea involves more preparation and time. Three to five days prior to the aeration process, add 2 tablespoons of microbe “food” such as ground oatmeal, soybean meal, fish emulsion or worm castings to the compost. Then add 2 tablespoons of a microbe catalyst that is high in minerals, such as rock dust; garden centers and hydroponics businesses carry these. Mix well and place in a warm (about 80 degrees F.), dark area.

After three to five days, place the sock of compost into the bucket and aerate for 24 to 36 hours. Strain the bucket contents to remove the solids and spray immediately.

Herring is impressed with how well compost teas and extracts have worked in his garden.

“My vegetable plants are more productive and the vegetables are more flavorful,” he said. “And I haven’t seen powdery mildew on any of my plants.”

Compost tea resources

The Master Composter & Recycler Program is sponsored by the Spokane County Regional Solid Waste System. Contact them through the Recycling Hotline at (509) 477-6800 or www.spokanecountysolidwaste.org.
“The Compost Tea Brewing Manual” by Elaine Ingham is available on the web at nofanj.org/LiteratureRetrieve.aspx?ID=104151.
“Teaming with Microbes” by Jeff Lowenfels and Wayne Lewis (Timber Press, 220 pages, $24.95), www.teamingwithmicrobes.com. [it’s teaming, not teeming]