Check out this quick post about the most widely used growing media in commercial aquaponics.
Commercial aquaponic systems must balance the growing environment for both fish and plants. A small error in nutrient availability, pH, or water temperature can have serious consequences. That’s why choosing the right growing medium is so important.
A good growing medium must meet the needs of both the plants and the grower. Strong healthy plants are produced in a medium that has good aeration and water retention, is not too heavy, doesn’t modify pH or clog the system. Several media meet these criteria. So, how do you choose?
That’s where grower preference and individual systems come in. Sometimes a determining factor is how easy a medium is to obtain and use. A readily available and consistent medium that is hygienic and doesn’t require pre-soaking saves time. And who doesn’t want more time?
Here are a few of the more widely used types of media:
FlexiPlugs®: Soil-Less Growing Medium

Quick Plug North America’s FlexiPlugs are created by blending the highest quality peat with other organics and a foam binder. The result is a light weight, stabilized propagation media that promotes faster rooting.
The FlexiPlug has optimal aeration and water retention capabilities. Our pH balanced plug also contains micronutrients and active biologicals which provide all the elements needed to promote healthy root growth and young plant vigor. FlexiPlugs do not require any pre-treatment. They don’t lose their shape so they are easy to handle and won’t clog your system.
Hydrocorn Clay Pebbles

Hydrocorn, considered to be a replacement for the discontinued Hydroton, is clay that is formed into little balls and then fired at high temperatures. This type of media is popular because it is light weight, drains well and is pH stable.
Its irregular surface is reportedly an improvement over the smoothness of Hydroton as the increased surface area allows for more growth of beneficial bacteria populations. Hydrocorn is reusable but must be sanitized between uses.
Rockwool
Rockwool is melted basaltic rock that is spun into fibers. It has been a popular medium in hydroponics for years. Horticultural grade, high quality rockwool has good water retention and drainage characteristics. It is pH neutral (There is some disagreement about this. Talk to your supplier.) It does not degrade so it won’t clog your filters. However, rockwool has fallen out of favor with some growers because it comes from a mined substance and must be thrown in a landfill after use. It also requires pre-soaking.
Pumice
Pumice is a type of volcanic rock. These stones are lightweight and very porous. The pores capture and store water and nutrients which means frequent watering is less necessary. Pumice drains well and comes in multiple sizes. It is reusable but requires sanitation between uses which can be labor intensive.
Learn more about growing media for commercial aquaponics.
Here is a video by Sylvia Bernstein of the Aquaponic Source
Here is a post on growing media for aquaponics by Backyard Aquaponics.
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