The Importance of Water Quality

By Leon Hussey

There are a number of parts to the puzzle of making AACT (Actively Aerated Compost Tea). Each part of the puzzle must be actively tested for its ability to positively or negatively impact the final quality of your compost tea. We are dealing with a live population of microorganisms that can used to address such concerns as disease and soil issues, nutrient cycling, or water quality. We must pay particular attention to the water, compost, foods, brewer, dissolved O2 levels, temperatures, ph, and the environment in which we produce and apply the tea. Within each of these elements there exist a number of variables that we must be attentive to in order to produce a high quality compost tea. I have dealt with a number of people in tea production internationally with varying success based on biological counts in the tea and what is seen in the plants and soils. Always trying to produce the best AACT, I started looking at variables at each location. Compost tea is an emerging field of study and practice and scientific research is just now able to confirm the beneficial impacts of using AACT. Because we are dealing with a complex process, small changes can have huge impacts on the final product. It therefore is imperative that we collect data and use scientific methods in evaluating the viability of our compost teas in order to ensure that what we are applying on our plants and soil is of the highest quality. This is only possible by testing our tea and determining the levels of beneficial organisms present in the tea. I often think of the functional diversity in old growth forests. A fire burns through it and everything changes - fire is the one element we added to the forest. In viewing the changed forest, the change is obvious. Without the use of a microscope, computer program, digital equipment and trained specialist we can't tell what we have in the tea. Testing is critical, especially in the beginning, to produce a tea that solves our problems. I would like to focus on water quality for AACT production. A client had a tea center for 2 years and was struggling to get good fungal numbers. He did all the chemical tests on his water and was told the water should work well for tea production. He then tested with another water source, keeping all other variables the same (brewer, temperature, time of day, compost, foods, etc.). The results showed he could produce good fungal numbers with one water, whereas the other water source had unacceptable numbers even though the chemical tests said each water should produce good tea. Because of the above experience, when setting up a farm with a 500 and 340 gallon brewer, we decided to test all of his water sources. We did the chemical tests and they were all acceptable for his tea production. The farm has 5 wells, a ditch, neighbor's water, RO (reverse osmosis), distilled and soft water without nitrates. All of the brews used the same compost, foods, temperature, time of brew and 5 gallon brewer. The only variable was the water source. These tests were done prior to setting up the tea production. Our goal was to identify the best water source. Water is a huge factor in the quality of tea produced.

H2O Active Fungal Total Fungal Hyphal Diameter
Distilled 1.34 14.7 4
Ditch 3.34 21.1 4
Well water w/o nitrates 1.67 3.91 4
Well #3 1.02 13.5 3
RO (reverse osmosis) .70 17.5 3
Soft water w/o nitrates .45 .96 2.5

From the above tests it becomes obvious the ability to produce good tea varies with the water source. Though not truly scientific (no 3 replications for each water tested), it gave us an idea of the best water to use. I would strongly recommend the testing of all your sources of water prior to production by making tea and having these tested (We have used the Soil Foodweb lab in Corvalis, Oregon). There is a huge difference between chemical tests of water and biological tests of what the water will support and grow in the brewing process. We found ditch water had the greatest biological potential. The farm is presently brewing 840 gallons 7 days a week and applying to potatoes through irrigation pivots. This farm is very good in evaluating, testing, replicating and searching for new tools to support them in their growing operation. I feel these are important factors in their continued success as farmers. Paying attention to the process and testing will lead to your success in brewing great tea.