Simple Compost Tea Brewer

Most trusted compost tea recipes

For the last 6 months I??have been testing various composts and compost tea recipes for our??indoor compost tea brewer. I??learned a lot. I??collected dozens of??recipes from various??sources, adjusted portions to fit our brewer??and run tests to see which combination fits best our "clean hands" process.??This is the first article in a series about this research.??At the moment I settled on KIS Organics compost and bacterial food for our compost tea bags, but I will keep running tests and I will keep following research on compost tea,??organic soil amendments and other biological gardening practices.

Why there are many different recipes at all?

While the basic recipe is very simple: water, compost and sugar, many gardeners and researchers??have their own??preferred way of brewing. Type of the compost tea you are brewing, duration of the brew, availability of the components and personal preferences result in dozens of different recipes. Also latest research shows that "classic" recipes with humic acid and kelp meal may not suitable for short brews (18-24 hours), but there are still plenty of references online to "classic" recipes containing??these ingredients.??

These recipes are for 64oz (1/2 gal) of water

All recipes in this article are adjusted for 64oz (1/2 gal, 2 liters) of water. Compost volume is measured in ounces. Because compost is relatively light I want to make sure - we are talking about fluid ounce which is about 1/8 cup or 6 tsp or 2 tbsp or 30ml. All other ingredients are measured in "tsp" (tea spoon) which is about a tea spoon or 5ml.

1. Microbe Organics

I consider Tim Wilson from Microbe Organics??the most trusted authority on aerated compost tea. He has been??experimenting with compost tea recipes for over 10 years. He looked at hundreds??of batches of tea in microscope, documented??how different ingredients affect microbial population and created a 4-hour video tutorial on??analyzing compost tea quality.

His most interesting observations:

Here??is the current version of his recipe adjusted for 64oz (1/2 gal)?????of the final product

Bacteria-dominated??Compost Tea Recipe (brew time 24-36 hours)

Vermicompost 1.5 oz
Black strap molasses 2 tsp
Fish hydrolysate 0.2 tsp

Fungal Brew (brew time 18-20 hours)

Fungal dominated compost 1.5 oz
Black strap molasses 1 tsp
Fish hydrolysate 1??tsp
Alfalfa meal 2 tsp

2. KIS Organics

Tad Hussey runs a personal site Gardening With Microbes??and a company Keep It Simple, Inc - both dedicated to compost tea??makers, composts and biological amendments. He works with Microbe Organics and runs his own tests through Soil Food Web testing lab. In my tests his compost and his microbial food mix performed the best in a tea bag form-factor.

Balanced compost tea recipe

Alaska Humus 0.3 oz
Vermicompost 0.3 oz
Fungal compost 0.3 oz
Blend of alfalfa meal,??feather meal, steamed bone meal, fish bone meal??and??natural calcite 2 tsp

3. Teaming with Microbes (the book)

Teaming with Microbes is the Winner of the 2011 Garden Writers of America Gold Award and also a??very??enjoyable read about soil biology. I read it on the plane in one sitting. This book??convinced me??on no-tilting and explained a lot about??how exactly??bacteria/fungi/protozoa help my plants.

Chapter 17 is fully dedicated to compost teas and here is the quick summary.

  • You cannot "overdo" applying aerated compost tea. Start with applying it twice a month. After establishing healthy soil food web population go to once a month and then three??times a year.
  • Sun kills microbes. Apply before 10am or after 3pm.
  • To be effective as foliar spray, compost tea must cover 2/3 of the leaf surface. You have to apply to both sides of the leaves.

Bacterial compost tea

Vermicastings or compost 4??oz
Nonsulfured??molasses or maple syrup 1.5 tsp

Fungal compost tea

Mix powdered oatmeal,??malt or soybean meal with your compost and let it sit for 3 days at 80F. At this point you should see a network of mycelia (white fluff)??

Fungally dominated??compost 4??oz
Nonsulfured??molasses or maple syrup 1 tsp
Fish emulsion 0.2 tsp
Powdered oatmeal,??malt or soybean meal 1 tsp

4. Compost Junkie??

Dave Dittmar has been "addicted" to compost for 15 years. He has been running CompostJunkie??website since 2010 and created??dozens of tutorials on how to compost and make aerated compost tea. His main point is that all human health starts in the soil, so take a good care of it. I totally agree with him but these recipes are??"classic" and use both humic acid and kelp. Research by KIS Organics and Microbe Organics shows that you need to avoid humic acids completely and avoid kelp for short brews (24 hours or less).

Balanced Compost Tea Recipe

Balanced compost 10 oz
Humic acids 1 tsp
Liquid kelp 0.5 tsp
Black strap molasses 0.5 tsp

Bacteria-Dominated Compost Tea Recipe

Bacteria-dominated??compost 10 oz
Cane sugar 1.5 tsp
Soluble??kelp 0.5 tsp

Fungal-Dominated Compost Tea Recipe

Fungal-dominated??compost 15 oz
Humic acids 1.5 tsp
Liquid kelp 0.5 tsp
Ground oatmeal 0.5 tsp
Yucca extract 0.2 tsp

Ultimate??Compost Tea Recipe

Vermicompost (worm castings) 1 oz
Fungal dominated compost 1 oz
Garden soil 1 oz
Forest soil 1 oz
Soluble black strap molasses 1 tsp
Soluble kelp 0.5 tsp
Humic acids 0.5 tsp
Fish hydrolysate 0.5 tsp
Rock dust 1 tsp
This is it for now. Pictures are coming soon in part 2.