About the Upstart Farmers Roundtables
Upstart Farmers Roundtables are an informal, biweekly event. Using Google Hangouts video calling, a small group of Upstart Farmers comes together to share their experiences and learn from each other. Each week is guided by a discussion topic, with growers welcome to ask their own questions.
Roundtables are exclusively for Upstart Farmers, and recordings are only released to the Upstart Farmers Community.
Roundtable: Beneficial Microorganisms for Hydroponics and Aquaponics
The Traditional View on Microorganisms in Hydroponics
In traditional hydroponic systems, growers sought to minimize biological diversity. The entire system existed in a “biological vacuum,” and growers used sterilizers, ozone, or UV clarifiers to eliminate microorganisms. If a hydroponic system did have a large microorganism population, they were most likely pathogens.
Aquaponic systems, on the other hand, were “dirty” in comparison due to their organic solids and lively microorganism population.
However, researchers and farmers began to notice that these super-clean hydroponic systems were more susceptible to disease when compared to aquaponic systems.
Today, many hydroponic growers are using microorganisms to increase diversity and inhibit disease with positive results.
Microorganisms for Hydroponic Systems
A wide variety of soil bacteria are available for use in hydroponic systems. Micorrhizal fungi have always been popular, but there are so many other kinds of microorganisms available for specific uses that it would be impossible for us to discuss them all.
Many applications of microorganisms are plant-specific, as each plant variety responds differently.
Even though there are many different types of microorganisms out there, the ones that you would use in a hydroponic system are the ones that are easy to culture and maintain – or the “domesticated” varieties.
Microorganisms for Aquaponic Systems
In aquaponic systems, nitrifying bacteria are the most common microorganism bacteria. Among many others, actinomycetes are a popular choice.
Dr. Nate is not a firm believer in this technique. It drops ammonia and nitrites quickly, but they will creep back up over time. Any additions then compete with the native, establishing bacteria in the system. While it sometimes provides a respite from the problem, a water change or feed change may have the same effect at a lower cost.
You must understand what the bacteria will do to your aquaponic system before adding it. In an aquaponic setup, you may need aeration or supplemental oxygen, or the dissolved oxygen (DO) will crash. This problem is not present in hydroponic systems.
Actinovate is a biological control that we do use frequently as a pest control in our aquaponic system. It can be added into the solution or applied foliarly. Actinovate specifically targets fungi and is OMRI approved for use in organic systems.
Carey Martin noted a concern his local hydroponic shop had with Actinovate turning into jelly and causing clogging. We’ve never had this problem, and hypothesize that you’d have to use an incredibly high dosage to have this affect.
Benefits of Microorganism Use
An Upstart Farmer can realize gains from microorganism use in a couple of areas. Microorganisms may be used to minimize or eliminate man hours associated with a negative activity, like removing sludge from aquaponic grow beds. (However, Tracy collects his sludge/fish emulsion and sells it for $5.00 per gallon.)
If your plants are suffering from a disease issue that’s causing depressed production, then increasing production by using a biological control will be valuable.
What about just using worms?
Worms are a great addition to many aquaponic systems, but there are times when you don’t want or can’t use them. Hydroponic farmers can’t use worms at all. Microorganisms are an alternative control.
We referenced a couple of our favorite products in this Roundtable. Here’s links:
Tracy’s Recommendation for an Aquaponic Pump: Pentair Dynamo